ICSV5 Table of Contents

5th International Congress on Sound and Vibration All RED areas are hypertext links. Position the mouse pointer over the link and click with your mouse button. The following hypertext documents may be followed to the papers presented at the conference. Use the Acrobat arrows at the top of the screen to recall previous pages.

Volume 1 • Volume 2 • Volume 3 • Volume 4 • Volume 5 • List of Sessions • Author Index •

Copyright Message Copyright 1997, The International Institute of Acoustics and Vibration Permission is hereby granted for any person to reproduce a fractional part of any paper herein, provided that permission is obtained from the author(s) and credit is given to the author(s) and these proceedings. Notiﬁcation to IIAV is not required. An author may reproduce his or her paper in full provided that these proceedings are credited. ICSV5 Introductory Material The following items contain introductory material about ICSV5 and this publication. The Table of Con- tents and Author Index (listed below) contain no hyperlinks. They are presented for reference only - Causal recommends that the HyperText versions above be used instead.

Notice • International Institute of Acoustics and Vibration • Chairman’s Message • Scientiﬁc Committee • Organizing Committee •

1 List of Sessions Active Noise Control, Page 1-173 • Active Vibration Control, Page 1-385 • Aeroacoustics, Page 2-513 • Architectural Acoustics, Page 2-729 • Boundary Element and Finite Element Methods, Page 2-793 • Condition Monitoring and Diagnostics, Page 2-903 • Damping - Passive and Active, Page 2-1091 • Distinguished Plenary Keynote Address, Page 1-3 • Environmental/community Noise, Page 3-1127 • Human Response to Sound and Vibration, Page 3-1183 • Machinery Noise Control, Page 3-1273 • Machinery Vibration Control, Page 3-1343 • Materials for Noise and Vibration Control, Page 3-1391 • Measurement Techniques, Page 3-1441 • Modal Analysis, Page 3-1527 • Musical Acoustics, Page 3-1581 • Noise Control Elements, Page 3-1651 • Non-Destructive Testing, Page 4-1717 • Non-Linear Acoustics and Vibration, Page 4-1771 • Numerical Methods, Page 4-1839 • Occupational Noise Exposure and Control, Page 4-1941 • Scattering of Sound, Page 4-1977 • Shockwave Dynamics, Page 4-2021 • Signal Processing, Page 4-2043 • Sound Intensity, Page 4-2231 • Statistical Energy Analysis, Page 4-2279 • Structural Acoustics and Vibration, Page 5-2347 • Structural Intensity, Page 5-2511 • Transportation Noise, Page 5-2553 • Transportation Vibration, Page 5-2653 • Underwater Acoustics, Page 5-2701 • Vibration and Shock, Page 5-2829 •

2 Volume 1 Distinguished Plenary Keynote Address A Century of Shock Wave Dynamics ...... I-3 Sir James Lighthill Recent Developments in Acoustics and Vibration ...... I-27 Malcolm J. Crocker Into the Physics of Rotor Aeroacoustics - Highlights of Recent European Helicopter Noise Research ...... I-59 Hanno Heller Recent Advances in the Active Control of Structurally Radiated Sound ...... I-103 Chris R. Fuller Vibration Suppression Through Smart Damping...... I-115 Daniel J. Inman Developments in Digital Analysis Techniques for Diagnostics of Bearings and Gears ...... I-133 R.B. Randall Hearing Protectors...... I-151 Samir N.Y. Gerges Active Noise Control Industrialization of Active Control Technologies ...... I-173 Christian Carme, Anne Montassier High-Performance Real-Time Computing Methods...... I-189 Osman Tokhi, D.N. Ramos-Hernandez, M.A. Hossain An Adaptive Sound Intensity Control Algorithm For Active Control Of Transformer Noise ...... I-205 Xiaojun Qiu, Colin H. Hansen Design of Curved Panel Sources for Active Control of Sound Radiated by Transformer ...... I-213 Xun Li, Colin H. Hansen, Xiaojun Qiu A Filtered-X Adaptive Notch Filter With On-Line Cancellation Path Estimation ...... I-223 A. Minguez, Manuel Recuero Implementation of Modal Filters for Acoustic Sensing of Sound Power Radiation ...... I-231 Kym A. Burgemeister, Scott D. Snyder Active Control of Structural Radiation Using Wavenumber Spectrum Measurements ...... I-239 Scott D. Sommerfeldt, Brian L. Scott Eﬀect Of Wall-Axial Wave Component on the Active Control of Water-Borne Noise in Steel Pipes...... I-247 Michael Podlesak Active Control of Machinery Noise in a Marine Environment - Lessons Learned...... I-255 Ronnie C N Leung Active Control of Cabin Noise in Aircraft - Lessons Learned? ...... I-263 Chris R. Fuller Use of a Water Impedance Tube to Evaluate the Performance of a Smart Skin Piston Element ...... I-271 Peter D Dean Feedback Control of Noise in a Room ...... I-279 Chaoying Bao, R. Paurobally, Jie Pan Active Equalisation of the Sound Field in an Extended Region of a Room ...... I-287 Arturo Orozco-Santillan

3 A Traveling Wave Approach to Active Noise Control in Ducts...... I-295 Jing Yuan, K.Y. Fung Study of Active Noise Control by Using Structural Acoustic Coupled Analysis ...... I-303 Shozo Kawamura, Atsushi Morita, Takuzo Iwatsubo, Koki Shiohata Strategies for Active Control of Sound Transmitted Through a Double-Panel Partition Using Distributed Actuators and Sensors ...... I-311 Xia Pan, Trevor J Sutton, S.J. Elliott Delayless Subband Echo Cancellation ...... I-319 Sven Nordholm, Joergen Nordberg A New Active Headset for a Helicopter Application...... I-327 Sven Johansson, Mathias Winberg, Thomas Lago, Ingvar Claesson New Approaches to Active Noise Control - Theory and Experimental Results ...... I-335 Marek Pawelczyk Industrial Applications of the Active Seat ANCAS ...... I-343 Christian Carme, G. Valentin Active Double Glazing: the Solution is the Transducer...... I-351 Christian Carme, Anne Montassier, M. Rehfeld ANC Headset: the Second Generation ...... I-359 Christian Carme, David Derrien, Pierre De Man A Solution for ANC Treatment in Flow Noise for Very Low Frequencies: a Product Named ACTA ...... I-367 Christian Carme, Virginie Delemotte, Pierre De Man Hybrid Controller: Theory & Product ...... I-375 Christian Carme, David Derrien, Pierre De Man Active Vibration Control Characterisation of Piezoelectric and Electrostrictive Materials for Acoustic Transducers: I. Resonance Methods ...... I-385 Binu K. Mukherjee, S. Sherrit Characterisation of Piezoelectric and electrostrictive Materials for Acoustic Transducers: II. Quasistatic Methods ...... I-395 Binu K. Mukherjee, S. Sherrit Pole-Zero Assignment of Vibratory System ...... I-405 Yitshak M. Ram Modal Filtering and Control of a Plate Using One-Dimensional PVDF Film Sensors ...... I-413 Nobuo Tanaka, Yoshihiro Kikushima Finite Element Analysis of Active Vibration Isolation ...... I-421 Carl Q. Howard, Colin H. Hansen Active Control of Nonlinear Vibration in a Flexible Cantilever Beam ...... I-429 Thanh Lan Vu, Jie Pan Active Control of Flexural Vibrations Using a Hybrid Mode/Wave Approach ...... I-437 C. Mei, Brian R. Mace, R.W. Jones Control of Structure-Borne Noise Transmission Using Electro-Rheological Fluid Inserts ...... I-445 N.R. Harland, Brian R. Mace, R.W. Jones Practical Realisation Issues In Adaptive Active Vibration Control ...... I-453 M.A. Hossain, Osman Tokhi Genetic Algorithms for Active Vibration Control ...... I-461 M.A. Hossain, Osman Tokhi Optimal Control of a Space Robot by the Nonholonomic Structure ...... I-469 Koichi Matsuda, Yoichi Kanemitsu, Shinya Kijimoto

4 AVIIS, Active Vibration Isolation in Ships ...... I-477 Thomas Lago, Mathias Winberg, Sven Johansson Modelling and Control of a Two Degree of Freedom Dynamic Absorber Using Shape Memory Actuator...... I-485 P.K. Boominathan, Y.G. Srinivasa, M. Singaperumal Neuro-Active Noise Control Using A Decoupled Linear/Nonlinear System Approach ...... I-493 Osman Tokhi, R. Wood Active Control of Machine-Tool Vibration in a Lathe ...... I-501 Ingvar Claesson, L. Hakansson

5 Volume 2 Aeroacoustics The Role of the Feedback Phenomenon in many Aeroacoustics Problems of Current Interest...... II-513 Krishnan K. Ahuja Quantification of Inflow Turbulence for Prediction of Cascade Broadband Noise...... II-515 Donald B. Hanson Acoustic Radiation From a Tandem Two-Plate Array in a Fluid Flow: Dependence on Array Geometry and Flow Regime ...... II-531 M.K. Bull, A.M. Blazewicz, J.M. Pickles Aeroacoustic Characteristics of Perforated Wall and Cavity ...... II-539 Kunisato Seto, Kiichi Tokuhisa, Muneharu Matsuoka Descriptions of Turbulence for Hydroacoustic Applications...... II-547 Stewart Glegg, William Devenport Random Vibration Response of a Cantilever Beam to Acoustic Forcing by Supersonic Rocket Exhausts During a Space Shuttle Launch ...... II-555 Ravi N Margasahayam, Raoul E. Caimi Nonstationary Transient Vibroacoustic Response of a Beam Structure...... II-563 Raoul E. Caimi, Ravi N Margasahayam, Jamal F. Nayfeh Experimental Estimation of Aerodynamic Noise Radiated From Ventilating Gas Exit of Vehicle Tunnels...... II-571 Yoshiyuki Maruta, Sadao Mori, Hiroo Tanabe Analysis of the Acoustic and Hydrodynamic Fields Downstream of a Sharp Edged Orifice in a Flow Duct System For Highly Turbulent Flows ...... II-579 Rolf C. Pedersen, Michael P. Norton New Approach to the Theory of Aerodynamic Sound ...... II-591 Alexander T. Fedorchenko Sonic Fatigue Study of an Aircraft Flap Like Structure ...... II-599 L.C. Chow, R.J. Cummins Effect of Non-Uniform Rotation on Acoustics and Aerodynamics of Propellers ...... II-607 S.R. Ahmed, J.P. Yin, W. Dobrzynski Computation Of Aircraft Noise Propagation Through The Atmospheric Boundary Layer ...... II-615 Johan B.H.M. Schulten Role of Enhanced Mixing on the Far-Field Noise of Supersonic Jets ...... II-625 Anjaneyulu Krothapalli The Low Frequency Acoustic Loading Vibration Response Analysis of Structures ...... II-627 Keiko Yoshida Dynamic Behaviour of the Airplane Horizontal Tail: Selection of the Model for Correct Simulation...... II-635 N.I Baranov, S.N. Baranov, Lev S. Kuravsky, K.P Zhukov Prediction of Aerodynamic Noise From Multi-Hole Multi-Stage Expansion in Control Valve ...... II-643 C.J. Gangadhara Gowda, Y.G. Srinivasa, Pramod S. Mehta The Effect of Nozzle Geometry on the Noise of High-Speed Jets ...... II-651 Christopher K. W. Tam An Influence of SST-2 Mixer-Ejector Nozzle Elements Variations on its Aerodynamic and Acoustic Characteristics ...... II-659 Sergey Ju. Krasheninnikov, Alexei Mironov, Eugeni V. Pavlyukov, Vladimir Jitenev, An- drey V. Shenkin

6 CFD- Analysis of Fan Aeroacoustics- Comparative Studies ...... II-669 Dieter Lohmann, H. Capdevila, U. Stark, M. Kuntz Numerical Simulation on Screech Tone Generated by Two-Dimensional Supersonic Jets ...... II-691 Tetsu Yamagishi, Shojiro Kaji Simulation of Aerodynamic Sound Generation on Airfoils in Low Mach-number Flows ...... II-699 G. Guidati, Siegfried Wagner Acoustic Effects on Flow Separation ...... II-707 Fritz-Reinhard Grosche Dynamic Behaviour of a Rectangular Unbaffled Plate Inmersed in a Diffuse Field ...... II-715 F. de la Iglesia, P. Garcia-Fogeda Architectural Acoustics Acoustical Planning of a Building Containing Both Apartments and a Theatre...... II-729 Leif Akerlof Room Acoustics Characterization Following a Phonon Transition Approach ...... II-735 Luis Bento Coelho, D. Alarcao The Variance of Pure Tone Reverberant Sound Power Measurements...... II-741 John L. Davy The Relevance of the Biot Theory for Prediction of Sound Transmission Through Partitions Incorporating Porous Layers...... II-749 Elizabeth A. Lindqvist Objective and Subjective Acoustical Parameters in Catholic Churches ...... II-757 Antonio P.O. Carvalho, Antonio E.J. Morgado Computer Prediction of Sound Propagation in Enclosed Spaces Using a Pressure Based Model ...... II-765 S.M. Dance, B.M. Shield Restaurants And Cinemas Downstairs: A Pleasure Or A Failure? ...... II-773 M. Asselineau Plasterboard on Masonry: The Effects of Direct Fixing ...... II-781 Mark Debevc Boundary Element and Finite Element Methods A Convenient Accuracy Criterion for Time Domain FE-Calculations ...... II-793 Morten Skaarup Jensen Comparative Study of Boundary Element and Finite Element Formulations for Evaluating Sound Radiation from Plates...... II-801 Jean-Pierre Coyette, Luc Cremers A Discussion on Finite Elemental Analysis of Sound Field in Rooms With Sound Absorbing Materials ...... II-809 Toru Otsuru, Tomoyuki Uchida Optimisation of a Concrete Block for a Diesel - Aggregate ...... II-817 Kari Saine, Olli Nuutila, Hannu Tienhaara An Introductory Study of the Convergence of the Direct Boundary Element Method...... II-825 Peter M. Juhl Effects of Drilling Degrees of Freedom in the Finite Element Modeling of Infinite Domains...... II-833 Jaehwan Kim Performance Evaluation of Finite Difference and Finite Element Methods in the Real-Time Simulation of Flexible Robot Manipulators ...... II-841 Osman Tokhi, Z. Mohamed, A.K.M. Azad

7 Low Cycle Carrying Capacity of Bearings With Hardened Rolling Layer...... II-849 Ivan Prebil, Robert Kunc, Matjaz Torkar FEM Complex Envelope Displacement (CED) Analysis for Damped High Frequency Vibrations ...... II-857 G. Verbeek, N.C.P.J. Geerts, Jan W. Verheij Finite Element Analysis of Gears in Mesh ...... II-869 Seney Sirichai, Ian Howard, Laurie Morgan, Kian Teh Acoustic Radiation From Finite Length Cylindrical Shells Using Boundary Element Method ...... II-877 Chong Wang, Joseph C.S. Lai Sound Pressure Levels Evaluation of a Compressor by BEM Method and Comparison with Experimental Measurements ...... II-885 Enrico Gargano, Alessandro Bartolini Equations in a Mixed Representation and a New Formulation by Finite Elements and Boundary Elements for the Resolution of a Vibro-acoustic Problem in the Presence of Non-uniform Mean Flow ...... II-893 Mabrouk Ben Tahar, Eugenie Goy Condition Monitoring and Diagnostics Some Recent Advances in Signal Processing for Vibration Monitoring ...... II-903 Joseph Mathew Gear Fault Detection Parameters Development Based on Modulation Techniques ...... II-919 G. Krishnappa Dynamic Behaviour of an Aircraft Power Take-Oﬀ Shaft Drive-System ...... II-927 Brian Rebbechi Predictive Maintenance of Rotating Machinery in NPP "PAKS" Based On Vibration Diagnostic Expert System ...... II-937 Istvan Nagy Eﬀects of Time Delay, Order of the FIR Filter and Convergence Factor on Self Adaptive Noise Cancellation ...... II-945 D. Ho, R.B. Randall Real Time Processing of Vibration Signal With Application to Slow Running Gearboxes ...... II-953 Krystof Kryniski Wear Detection in Turning Operations Using Neural Networks ...... II-961 A. Ghasempoor, Thomas N. Moore, J. Jeswiet Mechanical Signature Enhancement of Response Vibrations in the Time Lag Domain...... II-969 Yujin Gao, Robin Ford, R.B. Randall Use of Directional Spectra of Vibration Signals for Diagnosis of Misalignment in Rotating Machinery...... II-977 Chong Won Lee, Yun Sik Han, Young Seob Lee Bearing Diagnostics Based on Pattern Recognition of Statistical Parameters ...... II-985 Fengfeng Xi, Q. Sun, G. Krishnappa From Vibration Monitoring To Acoustic Signature Monitoring of a Ship ...... II-993 Bernard Garnier, D. Vaucher de la Croix, D Webster Frequency Analysis for Turbomachinery with Journal Bearings...... II-1001 Ian Howard, Adem Omerovic, Laurie Morgan The Application of the Block Vibration Characters of the IC Engines with The Fault Compressing Rings ...... II-1011 Y Zhang, Z. P. Zhang, Y.C. Zhou

8 Diagnosis for Radial Rolling Contact Bearing Using Acoustic Emission Technique (1st Report): Acoustic Emission Source Location Method ...... II-1017 Takeo Yoshioka, H Mano Dynamic Load Identiﬁcation in Gear Wheels on the Basis of Vibroacoustic Measurements ...... II-1025 Andrzej Wilk The Diagnosis of Bearing Defects Using Synchronous Autocorrelation Technique ...... II-1033 Wen Yi Wang Diagnostics of Gears Using Higher Order Spectral Analysis Techniques ...... II-1041 Stanislaw Radkowski A Study on the Fracture of a Sirocco Fan Impeller ...... II-1049 Seung P. Lee, C.O. Ahn, H.S. Rew, S.C. Park, Y.M. Park, D.I. Rhee Review and Prospects of Intelligent Diagnosis Technique for Spacecrafts ...... II-1057 Wenhu Huang, Xuexiao Wang, Xinwei Jiang Simulating Examinations of Vehicle Suspensions With Non-Linear Damping and Rigidity Characteristics ...... II-1065 Janusz Gardulski Simulation of Low Shaft Speed Bearing Faults Under a Heavy Load ...... II-1073 Yu-Fang Wang, Peter J. Kootsookos Frequency Estimation in the Fault Detection of Rolling Element Bearing...... II-1081 Yu-Fang Wang, Peter J. Kootsookos Damping - Passive and Active Frequency Domain Dynamic Analysis of Systems With Viscous and Hysteretic Damping ...... II-1091 F. Venancio-Filho Active Constrained Layer Damping on Cylindrical Shells ...... II-1103 Kam W. Ng Dependence of Active Damping Ratio to Feedback Gain and Stiﬀness in Vibration Control of Smart Structures ...... II-1109 Hyun Chul Park, Young Kyu Kang Impact Damper with Granular Materials for Multibody System ...... II-1117 Isao Yokomichi, Masaharu Aisaka, Yoshiaki Araki

9 Volume 3 Environmental/community Noise Informative Guidelines for the Assessment of Noise Annoyance ...... III-1127 Louis A. Challis An Overview of Environmental Noise Legislation Throughout Australia...... III-1135 Marco Ciccozzi, Tony Circelli, Richard French Experimental Studies of Sound Propagation in a Strongly Stable Atmospheric Boundary Layer ...... III-1141 Hans Olav K. Hygen Music Noise and the EPA’s Draft Guidelines ...... III-1149 Byron Martin, Carl Q. Howard Variation of Turbulence Effects along a Propagation Path...... III-1153 Ian Donald McLeod, Charles G. Don Further Reduction of Construction Noise in the Community...... III-1161 Wai-Keung Wong, W.K. Szeto, Sam W.H. Wong An Open Database on Propagation of Low Frequency Impulse Noise in the Atmosphere ...... III-1167 Lars Robert Hole, Robert L. Guice Recent Studies on Community Noise at Bahia Blanca City (Argentina) ...... III-1175 Liberto Ercoli, A.P. Azzurro, M.T. Piovan, A. Alvarez, J. Smael Human Response to Sound and Vibration Linear Response of the Cochlea...... III-1183 David Alan Bies Impulse Noise From Firearms ...... III-1195 Antonio Miguel Mendez, Edmundo Carlos Rochaix Investigation of Subsonic Oscillations Influence on Aircraft Personnel Working Under Nervous Psychophysiological Overloads ...... III-1203 Michael M. Samoylov, G.M. Ponomarenko, Pavel V. Vorobjev, V.V. Zaytseva Traceability and Uncertainty of Low-Frequency Vibration Measurements ...... III-1207 Norman H. Clark, Laurence P. Dickinson Sound Quality of Wind Turbines...... III-1215 Reinhard Weber, Christoph Eichenlaub Relation Between TRICC and Sound Image Perception in a Sound Field with a Single Echo ...... III-1223 H. Yanagawa, Tetsuo Tagaeto, H. Komatsu Finite-Element Method Analysis of the Normal and Reconstructed Middle Ear ...... III-1231 Takuji Koike, Hiroshi Wada, Toshimitsu Kobayashi The Significance of the Vibration Direction for the Subjective Evaluation of Dual-axis Whole-body Vibrations ...... III-1239 Barbara Griefahn, Peter Broede, Wolfgang Jaschinski Low Frequency Noise in Domestic Environment: Measurement Results and Assessment of Annoyance ...... III-1247 Marianna Mirowska Visual Contrast Thresholds During Single - Axis and Dual - Axis Whole Body Vibrations ...... III-1255 Barbara Griefahn, Peter Broede, Wolfgang Jaschinski Detection Enhancement Using Colour for Sonar Displays ...... III-1263 Ross L. Dawe, Edwin R. Galbreath

10 Machinery Noise Control The Influence of Internal Structures on the Sound Radiated From a Machinery Hood...... III-1273 L. Oddo, B. Laulagnet, Jean-Louis Guyader Quantifying the Noise Emission of Engine Oilsumps, Valve Covers, etc. Using Artificial Excitation ...... III-1283 P.J.G. van der Linden, J. Schnur, T. Schomburg Effect of Tooling Parameters on the Relationship Between the Radiated Noise and Induced Force in Shear Cutting of Sheet Metals...... III-1293 Ahmad Bahrami, Hugh M. Williamson, Joseph C.S. Lai Hermetic Compressor Noise Control by Shell Modifications ...... III-1301 N J Agrawal, R. Dubey, S.R. Joshi Control of the Sound Generated by a Rotary Compressor...... III-1309 Nelik Dreiman Determination of Limit Admissible A-weighted Noise Emission Values of Machinery and Equipment ...... III-1317 Ilja E. Tsukernikov Simulation Tests in the Indicatory Acoustic Assessment of Machines...... III-1325 Zbigniew Engel, Dariusz Pleban An Analysis of the Flow and Sound Source of an Annular Type Centrifugal Fan ...... III-1333 Wan-Ho Jeon, Duck Joo Lee Machinery Vibration Control The Effect of Workpiece Torsional Flexibility on Chatter Performance in Cylindrical Grinding ...... III-1343 R.D Entwistle, Brian J. Stone Vibration and Idling Noise in Commercial Circular Saws ...... III-1351 Victor Poblete, Jorge P Arenas, Rolando Rios, E. Millar Vibration Insulation of Test Benches for Comfort and Fatigue Assessment of Cars ...... III-1359 Pietro Croce, Pietro Orsini, Walter Salvatore Structure Born Vibrations of Spindle and Their Scattered Energy ...... III-1367 M. Abdul Mazid, Nong Zhang, M. Alauddin, M.J.S. Hashmi Noise and Vibration Minimizing in Machines Threated as Multi-Sources System ...... III-1375 Zbigniew Dabrowski Modeling of Electromagnetic Excitation Forces of an Induction Motor for Vibration and Noise Analysis ...... III-1381 Dae-Hyeon Cho, Kwang-Joon Kim Materials for Noise and Vibration Control Improved method for estimating complex modulus and damping...... III-1391 Sven Gade, Niels Johan Wismer Characteristics of Chiral Slab in the Applications of Wave Absorption ...... III-1399 C.C. Sung, Ro Ruyen, Yuh-Ming Chang Acoustical Properties of Ferrous Metal With One and Two Alloying Elements ...... III-1407 Nelik Dreiman Using Frequency Limited Propagation Data to estimate the Tortuosity of Porous Materials ...... III-1415 David E. P. Lawrence, Charles G. Don Wave Propagation in Layered Transversely Isotropic Fluid-Saturated Porous Media ...... III-1423 Yue Sheng Wang, Zi Mao Zhang, Gui Lan Yu Measurements of Frame Motion In High Intensity Sound Propagation Through Flexible Porous Materials...... III-1431 Konstantin Khirnykh, Alan Cummings

11 Measurement Techniques Solar Opto-Hydraulic Laser as a New Technology in Vibration Engineering...... III-1441 Anatoly T. Sukhodolsky Calibration: Primary, Secondary, and Field...... III-1451 Ernst Schonthal Vibrations in Roller Chain Drives...... III-1459 Thomas Kell, P. Fritz, F. Pfeiffer Unsteady Pressure Measurement: Correction of the Resonance of the Pneumatic Line...... III-1467 Stephane Gabard, J. Peube, Christophe Picard Power Flow Using Electro-Optic Holography, Part 1: Obtaining the Structural Phase ...... III-1475 Gary A. Fleming, Jonathan D. Blotter Real-Time Vibration Mode Imaging Using Photorefractive Holography...... III-1483 Ken L. Telschow, V.A. Deason MALICE, the Efficient Acoustic Imaging System for Precise Noise Source Localization ...... III-1491 D. Vaucher de la Croix, D Webster, Bernard Garnier, F. Molliex A New Tool for Sound Proofing Inspection: the SALSA System ...... III-1499 D. Vaucher de la Croix, Bernard Garnier, D Webster, F. Molliex Airborne Acoustic Detection and Localization of Transients...... III-1505 Bernard Garnier, F. Molliex, D. Vaucher de la Croix, D Webster Quality controlled separation of outdoor noise component(s) contributed by continously working plants applying online measured Lx-confidence limits...... III-1511 Alois Heiss Bringing Order into the Chaos of Multichannel Systems Using Transducers with Integrated Identification...... III-1519 Jrgen Bðkke, Helge Larsen, Birger Kriegbaum, Bernard Ginn Modal Analysis System Identification of Piezoceramic Beams ...... III-1527 Bor Tsuen Wang, Rong Liang Chen Method for Problem of Khladni Figures Solution ...... III-1535 Michael S. Sedov Support Conditions, Their Effect on Measured Modal Parameters ...... III-1539 Thomas G. Carne, Clark R. Dohrmann Theoretical and Experimental Study of a Generalized Pseudo-Forces Method for Source Characterization ...... III-1547 M.H.A. Janssens, C.M. Langeveld, Jan W. Verheij Experimental Spatial Matrix Identification Method (Presentation Of Current Theory And Fundamental Verification) ...... III-1555 Masaaki Okuma, Tatsuya Oho Nonlinear Bending - Torsion Modal Interation Under Parametric Excitation...... III-1563 Raouf A Ibrahim, M. Hijawi Updating of Non-Conservative Structure Via Inverse Methods with Parameter Subset Selection ...... III-1571 Ladislav Starek, Daniel J. Inman, Milos Musil Musical Acoustics Mode Studies in Musical Instruments...... III-1581 Uwe J. Hansen

12 The Bell - Where Do We Stand Today? ...... III-1593 Hervey Bagot Mode Coupling in Tone Sections of a Tenor Steel Pan ...... III-1601 Uwe J. Hansen, Thomas D Rossing Binaural Recordings and Their Application in the Subjective Assessment of Music Rooms and Concert Halls ...... III-1609 Riduan Osman Use of an Auditory Model to Explain the Mechanism of Pitch Discrimination...... III-1617 Suhashini Shankar, Suzanne Hogg The Evolution of Partials in Polyphonic Piano Sounds...... III-1625 Lucile Rossi, G. Girolami Damping of Bells using Experimental and Numerical Methods...... III-1633 M.H. van Houten, A.J.G. Schoofs, D.H. van Campen Tuning Marimbas Using Numerical Optimization ...... III-1641 Katherine A. Legge, J. Petrolito Noise Control Elements Optimization of Acoustical Shields ...... III-1651 Nikolay I. Ivanov, Alexander V. Omelchenko, Michael M. Samoylov, Vladimir N. Uskov, Natalia V. Zuyzlikova Finite Element Analysis of an Industrial Reactive Silencer ...... III-1659 Ben Cazzolato, Carl Q. Howard, Colin H. Hansen High Frequency Ray Acoustics Models for Duct Silencers ...... III-1669 Alan Cummings A New Noise Reduced Construction for Exhaust of Powerful Internal Combustion Engines ...... III-1677 Pavel V. Vorobjev, Lyudmila Ph. Drozdova, Michael M. Samoylov The Attenuation of Noise Entering Buildings Using Quarter-Wave Resonators: Results from a Full Scale Prototype...... III-1683 C.D. Field, F.R Fricke The Design Technique for Reducing the Intake Noise of a Vehicle ...... III-1691 Jae Eung Oh, Kwang Hee Han Characteristic Boundary Conditions and its Application to Resonance Tube ...... III-1699 Seung Chul Kwak, Ho Seon Rew, Duck Joo Lee Analysis of Extended-tube Three-pass Perforated Element Muﬄer by Means of Transfer Matrices ...... III-1707 M.L. Munjal

13 Volume 4 Non-Destructive Testing Non Destructive Evaluation of Polymers: Some New Developments ...... IV-1717 G. Busse Non-Destructive Estimation of the Position of a Crack in a Concrete Block ...... IV-1725 Masato Abe, Kenji Sasaki Enhanced Parameter Identification for Damage Detection in Aerospace Structures Using "Twin" Structures Concept ...... IV-1733 Pavel M. Trivailo, L.A. Plotnikova, L.A. Wood Ultrasonic Loss Angle Imaging with Speckle Interferometry ...... IV-1741 A. Salerno, S. Danesi, D. Wu, S. Ritter, G. Busse Cure Monitoring of Thin Adhesive Layers ...... IV-1747 D. Geisse, K. Nixdorf, G. Busse Remote Vibrometry for Characterisation of Materials and Processes...... IV-1755 Ch. Doettinger, J. Stanullo, Leonid M. Lyamshev, G. Busse Non-Destructive Testing of Composites Using Long Waves ...... IV-1761 Suzanne Thwaites, Norman H. Clark Non-Linear Acoustics and Vibration Various Methods for Nonlinear Noise and Vibration Signal Processing...... IV-1771 W S Gan Non-Linear Response of Acoustically Excited Panels ...... IV-1779 A.J. Clark, L.J. Schmid, David C. Rennison Resonant Oscillations Governed by the Boussinesq Equation With Damping ...... IV-1785 Shamil U. Galiyev Wave Localization in Hydroelastic Systems ...... IV-1797 A.K. Abramian Aeroelastic Response of a Three Degree of Freedom Wing-Aileron System with Structural Non-Linearity...... IV-1807 S.A. Safi, D.W. Kelly, R. Mohajeri Nonlinear Radiation of a Piston Vibrating with a High Amplitude ...... IV-1815 Valery G. Andreev, N.B. Brandt, O.V. Rudenko Nonstationary Vibrations in a Catenary-Vertical Hoisting Cable System ...... IV-1821 Stefan Kaczmarczyk Linear Modeling of the Dynamics of an Electrodynamic Piston Compressor ...... IV-1829 Gyu-Sang Choe, Kwang-Joon Kim Numerical Methods Time-Domain Computation of Acoustics in Confinements ...... IV-1839 K.Y. Fung Transient Wave Envelope Elements for Unbounded Problems ...... IV-1847 R.J. Astley A Linear Method for Local Structural Modification...... IV-1855 Tao Li, Jimin He Mathematical and Computer Modelling of Transitional Processes in Transmissions Incorporating High Torque Harmonic Drives ...... IV-1863 Vladis Kosse, Joseph Mathew Numerical Computation of Exhaust Noise Through Perforated Diffuser Using Optimized High-Order Compact Schemes ...... IV-1871 Jae Wook Kim, Duck Joo Lee

14 A Wave Based Prediction Technique for Vibro-Acoustic Systems With Cylindrical Shell Components ...... IV-1879 Wim Desmet, P. Sas, D. Vandepitte Simulation of Friction in Oscillating Mechanisms ...... IV-1891 D.W. Lee, D.C. Hesterman, R.W. Jones An Efficient Numerical Procedure for Approximating Acoustic Diffuse Fields ...... IV-1899 Jean-Pierre Coyette, Christophe Lecomte, Karl Meerbergen Dynamical Behaviour of Variators with a Half Ball as a Non-Holonomic System ...... IV-1907 Miodrag Zlokolica Frequency Analysis of Composite Beams using a Higher-Order Beam Element ...... IV-1915 Guangyu Shi, K.Y. Lam, T.E. Tay Vibratory Conveyance of Granular Materials ...... IV-1923 Masato Saeki, E. Takano An Elliptic Perturbation Method for Certain Strongly Non-linear Rotors ...... IV-1931 Livija Cveticanin Occupational Noise Exposure and Control Some Principle Points of Noise Legislation in Slovenia ...... IV-1941 Ferdinand Dezelak Interest of Predictive Simulation for Noise Level Assessment at the Work Place ...... IV-1951 Claude Michel, Michel Delfosse Noise at Work - Principles of Risk Assessment ...... IV-1959 Danuta Augustynska, Dariusz Pleban, Dariusz Puto The Difficulties Associated with Determining Industrial Hearing Loss ...... IV-1967 David Eager Scattering of Sound Direct and Inverse Scattering of Penetrable and Nonpenetrable Obstacles by Shape Deformation ...... IV-1977 D.N. Ghosh Roy, Luise S. Couchman, Jeremy Warner Sound Wave Scattering From an Air Filled Shell in a Layer of Liquid ...... IV-1985 Alex Zinoviev Diffraction of Bending-Gravitation Waves on Crack in Ice Field...... IV-1995 Dmitri Azalinov Sound Reflection From Vibrating Surface ...... IV-2003 Noboru Watanabe, Yoshio Yamasaki Acoustic and Elastic Wave Scattering from a Rigid or Soft Cylinder ...... IV-2011 Huinam Rhee, Youngjin Park Shockwave Dynamics Shock Propagation in the Presence of Time-Dependent Perturbations...... IV-2021 D.G. Crighton Weak Shock Reflection ...... IV-2023 John K. Hunter, Moysey Brio Hysteresis Phenomena in Shock Wave Reflections in Steady Flows ...... IV-2031 Gabi Ben-Dor The Propagation of Weaks Shocks in Non-Uniform Flows ...... IV-2039 N. Kevlahan Signal Processing Application of Harmonic Wavelets to Time-Frequency Mapping ...... IV-2043 David E. Newland

15 Stochastic Signal Information Processing for Acoustic Environment — Use of Wide Sense Digital Filter...... IV-2055 Mitsuo Ohta, Akira Ikuta Analyzing Time-varying and Transient Vibration Properties in Technological Systems ...... IV-2071 Alexandros Soumelidis, Jozsef Bokor, Istvan Nagy Speech Signal Enhancement Based on a Sinusoidal Model ...... IV-2079 Michiko Kazama, Takahiro Ohnishi, Mikio Tohyama Mutual Correlation Characteristics Between Sound Level and Electric Field Intensity Fluctuation in Connection With Electromagnetic Environmental Problem of VDT Games ...... IV-2087 Hitoshi Ogawa, Mitsuo Ohta A Prediction Method for the Stochastic Response of Complicated Soundwall Systems on an Intensity Scale Without Introducing any Artificial Error Criterion ...... IV-2095 Naomitsu Takaki, Mitsuo Ohta An Evaluation Method of the Complicated Acoustic System Based on the Neural Networks Reflecting the Statistical Structures ...... IV-2103 Noboru Nakasako, Yasuo Mitani, Mitsuo Ohta A Precise Estimation Method Matched to Digital Level Measurement for the Probability Distribution of Sound, Light and Electromagnetic Fluctuations Leaked From VDT ...... IV-2111 Yasuo Mitani, Mitsuo Ohta A Dynamic Estimation Method of Low-frequency Objective Sound in the Outdoor Measurement Contaminated by Wind Noise...... IV-2119 Yoshiaki Takakuwa, Mitsuo Ohta, Masafumi Nishimura, Hideo Minamihara An Estimation Method of Original Stochastic Information in Non-Gaussian Random Signals With Amplitude Limitations ...... IV-2127 Hideo Minamihara, Mitsuo Ohta, Naomitsu Takaki, Masafumi Nishimura A Stochastic Evaluation Method on the Level Crossing of Wave Form for the Road Traffic Noise ...... IV-2135 Shoji Kodani, Mitsuo Ohta Static and Dynamic Signal Detection Methods for Road Traffic Noise Environment Based on Fuzzy Observation...... IV-2143 Akira Ikuta, Mitsuo Ohta Output Probability of an Environmental Vibratory System with a Non-linear Feedback Element ...... IV-2151 Seijiro Hiromitsu, Mitsuo Ohta A Probabilistic Evaluation Method for Various Type Sound Insulation Systems Based on Kullback’s Information Criterion and Mixed Type Non-stationary System Model...... IV-2159 Yoshifumi Fujita, Mitsuo Ohta Acoustic Signal Processing Using Multi-Windowed STFT and Harmonics Sieving ...... IV-2167 Takahiro Ohnishi, Michiko Kazama, Mikio Tohyama Blind Dereverberation Using an Iterative Short-Time Cepstrum Subtraction Method .....IV-2175 Jean S. van Eeghem, T. Koike, Mikio Tohyama Analysis and Visualization of Room Acoustic Chaos ...... IV-2181 Yoh-ichi Fujisaka, Mikio Tohyama, Akira Sugimura Towards More Effective Prediction Of On-Road Wind Noise Characteristics From Wind-Tunnel Tests...... IV-2189 Peter O’Shea, Simon Watkins, Christian Peric, Bruce Sloss Spectral Estimation Errors When Using FFT Analysers ...... IV-2197 Thomas Lago, Ingvar Claesson

16 A Qualitative Dynamics-Based Discrete Holographics Method for Vibration Signal Analysis ...... IV-2205 Fengfeng Xi Methods for Computing the Passive Wideband Cross Ambiguity Function...... IV-2213 Kam W. Lo, Brian G. Ferguson A Proof of the Variance Formula for the Total Crossing Time of a Continuous Random Sound Signal With Respect to a Fixed Level ...... IV-2221 Alois Heiss Sound Intensity Sound Intensity and its Measurement ...... IV-2231 Finn Jacobsen A Critical Revision of ISO Standard 9614-1: Determination of Sound Power Levels of Noise Sources Using Sound Intensity ...... IV-2247 Monica Carfagni, Marco Pierini Sound Intensity Vector Fields in Relation to Different Reference Signals ...... IV-2255 Orjan Johansson A Method to Correct the 3D Active and Reactive Sound Intensity Vectors Using a Rotating 1D Probe in an Unsteady Acoustic Field...... IV-2263 Christophe Picard, J.C. Patrat, A. Duran, H.S. Na, J.C. Rebillat On the use of the Sound Intensity Method for Detecting Noise Sources near the Reflecting Planes...... IV-2271 Sung-Chon Kang, Jeong-Guon Ih Statistical Energy Analysis Energy Flow and S.E.A. At Low Modal Overlap...... IV-2279 Brian R. Mace Predictive Statistical Energy Analysis and Equally Spaced Point Connections ...... IV-2287 Ken H. Heron Statistical Energy Analysis of a High Speed Elevator Cab and Frame ...... IV-2295 Charles D. Coffen, Larry Hardin, Tricia Derwinski New Procedure of Vibration Analysis Using Statistical Energy Analysis: Case of Box-Like Structure ...... IV-2305 Minoru Kamata, Toru Yamazaki, Kazuaki Kurosawa, Shinichi Ohno Energy Flow Models From Finite Elements: An Application to Three Coupled Plates .....IV-2313 P.J. Shorter, Brian R. Mace The Limitation in the Sea Prediction of Power Transmission and Energy Distribution ...... IV-2321 Ruisen Ming, Jie Pan Method to Determine Structure-Borne Noise Level From Machinery In Sea Application...... IV-2329 Sang R. Kim, Jae S. Kim, Hyun S. Kim, Hyun J. Kang Combined FEA/SEA Vibration Analysis ...... IV-2337 Anders M. Wilson

17 Volume 5 Structural Acoustics and Vibration Uncertainty of Vibroacoustic Behaviour of Industrially Identical Structures-ANew Challenge for Structural Acoustic People...... V-2347 Jean-Louis Guyader, E. Parizet Machine Bases as Structure-Borne Sound Sources ...... V-2359 Barry M. Gibbs Smart Sensors for Measuring the Acoustic Power Mode of a Planar Structure ...... V-2375 Yoshihiro Kikushima, Nobuo Tanaka A Study of the Transmission of Noise and Vibration in an Aluminium Motor Vessel ...... V-2383 Yan K. Tso, Ross G. Juniper Structural Sensing of Sound Transmission into a Cavity for Active Structural-Acoustic Control ...... V-2391 Ben Cazzolato, Colin H. Hansen Axisymmetric Transfer Functions along a Fluid Filled Elastic Tube ...... V-2403 Roger J. Pinnington Approximating Eigensolutions Of Distributed Structures Using Adjustable Base Functions ...... V-2411 Jie Pan Radiation From Partially Excited Plates ...... V-2419 R.A. Novak Acoustic Radiation from Structures: the Frequency Averaged Quadratic Pressure Prediction ...... V-2429 Jean-Louis Guyader, Thierry Loyau The High-Frequency Vibration and Sound Radiation of a Homogeneous Plate With Internal Losses...... V-2437 V.U. Kirpichnikov, A.A. Juravleva, Lyudmila Ph. Drozdova Sound Radiation of Plate Excited by a Force of an Arbitrary Angle Direction ...... V-2443 V.U. Kirpichnikov, V.V. Savenko, Lyudmila Ph. Drozdova Source Descriptors for Structure-Borne Sound Sources...... V-2449 A T Moorhouse, J.M. Mondot, Barry M. Gibbs Vibration Analysis of Rotor Bearing Pedestal Systems ...... V-2457 N.S. Feng, E.J. Hahn Low and Mid-frequency FRF Modelling of Engine Subframe and Car Body Interaction for Vibratory and Acoustical Response Evaluation ...... V-2465 Katrien Wyckaert, G. Toniato, K.Q. Xu Estimation of Surface Mobility of an Inﬁnite Plate for a Square Contact Area by the Finite Element Method...... V-2477 Yuejun Li, Hugh M. Williamson, Jue Dai, Christopher J. Norwood Surface Mobility for a Rectangular Contact Region Under a Uniform Velocity Distribution ...... V-2493 Jue Dai, Hugh M. Williamson, Yuejun Li Variational Formulation by Integral Equations for the Resolution of Vibro-acoustic Problems in a Visco-thermal Fluid ...... V-2501 C. Karra, Mabrouk Ben Tahar Structural Intensity Crack Detection in Beams Using Structural Intensity ...... V-2511 Christopher J. Norwood

18 Bias Errors in Measurement of Vibratory Power and Implication for Active Control of Structural Vibration ...... V-2519 Mogens Ohlrich, E. Henriksen, S. Laugesen Conservation of Energy and Model Convergence Using Experimental Spatial Power Flow ...... V-2527 Jonathan D. Blotter, Gary A. Fleming, Robert L. West Evaluation of the Effect of Damping Treatment Using Approximated Vibration Mode Shapes ...... V-2535 Hisami Ohishi, Shinichi Ohno Practical Approach of Structural Intensity Measurement Applied for Box-Like Structure ...... V-2543 Toru Yamazaki, Minoru Kamata, Shinichi Ohno Transportation Noise How Can We Improve Ways To Describe Future Noise Impacts To Decision Makers And The Community? The Lessons From Sydney Airport ...... V-2553 David Southgate, P. Pieruschka The Noise Impacts Associated with a Major Road Infrastructure Project in a Developing Nation ...... V-2563 Stephen Samuels, Weeradej Cheewapattananuwong A Preliminary Traffic Noise Investigation in an Acoustically Upgraded Dwelling...... V-2569 Tony Circelli, Cecilia Bukutu Aircraft Noise in Sydney - Community Reaction in Areas Between 15 and 30km North of the Airport ...... V-2581 Ernestine M.A. Gross, Ah Boon Sim Effects of Traffic Noise Within the Madrid Region ...... V-2593 Manuel Recuero, C. Gil, J. Grundman Heavy Vehicle Noise Reduction Strategy ...... V-2601 Peter Karantonis, Najah Ishac, Renzo Tonin Modeling of Urban Traffic Noise ...... V-2609 Momir Prascevic, Dragan S. Cvetkovic, A.S. Deljanin, V.O. Stojanovic A Proposed Compression Brake Noise Test Procedure ...... V-2615 Thomas E. Reinhart, Thomas J. Wahl Effectiveness of Insulation Program for Houses Around Sydney Airport ...... V-2623 Marion Burgess Modelling In-Vehicle Engine Noise (Listen to the Noise Paths) ...... V-2629 Patrick Van de Ponseele, S. Campino, Filip Deblauwe, Geert Lowet Numerical Study on the Radiation of Intake Noise from Internal Combustion Engine by Using Essentially Non-Oscillatory Schemes...... V-2635 Yong Seok Kim, Duck Joo Lee Characteristics of Compression Brake Noise ...... V-2643 Thomas E. Reinhart, Thomas J. Wahl Transportation Vibration Vibration Generated by Underground Railway Trains ...... V-2653 Hugh E.M. Hunt, Jonathan E. May Optimization of Noise and Vibration Protection Approaches in Movable Compressors ...... V-2661 Lyudmila Ph. Drozdova, Nikolay I. Ivanov, Alexander V. Omelchenko, Vyacheslav V. Potekhin

19 Vibration Isolation Performance of Floating Slab Track Used in Underground Railways ...... V-2665 James A. Forrest Models for an Elevator Hoistway Vertical Dynamic System ...... V-2673 Yue Qi Zhou Prediction of Ground Vibration Induced by High-Speed Train Operation ...... V-2681 Hirokazu Takemiya, Kazuya Goda Random Vibration of Engine-Mounting System with Motion-Limiting Stops ...... V-2689 Masaharu Aisaka, Isao Yokomichi, Yoshiaki Araki, Takeshi Inoh Underwater Acoustics Acoustic Variability and Sonar...... V-2701 Adrian D. Jones Prediction of Line-Spectrum Noise Induced by Underwater Vehicle Contra-Rotating Propellers ...... V-2721 Xiqing Zhu, Wusheng Wu Optimal Pulse Shaping in Reverberation - Limited Environments...... V-2729 Henry Lew, R.F. Barrett Trapped Modes In Elastic Constructionbs Lying in the bottom of a Channel of Non-Compressible Weight Liquid ...... V-2739 Dmitri Indeitsev, V. Alekseev, Yu Mochalova Transmission Loss: Comparisons Between Experimental Data and Normal Mode Predictions Based on a Seafloor Lithology Database ...... V-2747 Ashley Ian Larsson Initial Shallow Water Bottom Loss Measurements in the Timor Sea...... V-2755 Graham D Furnell, Graham J. Day The Effectiveness of Sparse Random Arrays For Underwater Acoustic Imaging ...... V-2765 David G. Blair, Jim Thompson, Stuart Anstee Acoustic Seabed Models Obtained by Inverting Explosive Shallow Water Transmission Loss Data ...... V-2773 Marshall V. Hall Propagation of a Low-frequency Sound in a Hydroacoustic Waveguide with the Thin Ice-floe of Finite Width Laying on a Surface ...... V-2781 Sergey M. Grudskii, S.S. Mikhalkovich Shallow Water Propagation Modelling from 5HZ to 25KHZ ...... V-2789 David N. Matthews, Marshall V. Hall, B.L. Jessup Cross Correlation of Directional Sonobuoys ...... V-2797 Edwin R. Galbreath, Ross L. Dawe Attenuation of Acoustic Waves by a Thin Cylindrical Bubbly Layer...... V-2805 Patrick Yeung, Allen T. Chwang Ambient Sea Noise in Australian Waters ...... V-2813 Douglas H Cato Experimental Investigation of the Influence of Magnetic Field on the Cavitation Inception in Pulse Rarefaction Waves in Water ...... V-2819 Alexey S. Besov Vibration and Shock Thermodynamics of Vibrations Induced by Continuous Light in Liquids ...... V-2829 Anatoly T. Sukhodolsky Digital Control Discrete Models of Active Vibration Isolation...... V-2839 Larisa A. Rybak

20 The Yo-Yo as a Structural Vibration Exciter - Force Time Histories ...... V-2845 Leonard L Koss Factorization Method in Annular Plates Vibrations ...... V-2855 Dumitru Caruntu An Experimental Investigation into Torsional Vibration in Ball Mills ...... V-2863 R.M. Heidecker, S.J. Drew, Brian J. Stone Discovering the Rectilinear Model of Complex Torsional Vibratory Systems With the Aid of Bond Graphs ...... V-2871 Kazem Abhary Some Aspects of Interfacial Motion Relevant to Forced Oscillations...... V-2879 Sead Spuzic, Ian Reid, Milorad Zec Studies on the Vibrating Systems with Collision - Rebound Characteristics of the Equivalent Stiff Surface...... V-2889 Sadao Azuma, Hiroyuki Ishida, Shunichi Kono Isolation of Buildings From Railway Vibration: A Case Study...... V-2897 Dave Anderson On Stiffened Plate Vibration...... V-2905 Boris M Efimtsov Experimental Determination of the Complex Moduli of Hereditary-Elastic Materials Used as Isolators...... V-2913 Stanley G Hutton, Guoping Chen Vibration Absorbers and Metallic Damping Layers ...... V-2921 Oskar Bschorr, H. Albrecht A Formulation for the Forced Vibration of a Multi-Supported String ...... V-2929 Benjamin A. Cray Analysis of Coupled Vibration for the Elastically Supported Beam and Spring-Mass System ...... V-2937 Yun S. Ryu, Chong D. Choi, Hee B. Cho Coupled Stress Distribution in a Vibrating Rod Subjected to Variable Temperature and Moisture ...... V-2945 R.A. Heller, S. Thangjitham, A. Szekeres Complete Program System for Analysis and Optimization of Rolling Rotational Connections...... V-2953 Samo Zupan, Ivan Prebil, Pavle Kaiba Parametrically Excited Vibrations of Plates Subjected to Pulsating Loads ...... V-2963 Juergen Buellesbach, Oliver Fischer Smart Nonlinear Structures of Vibration Isolation ...... V-2971 V.I. Babitsky, A.M. Veprik Free Vibration of A Cantilever Beam with A Partial Span of Distributed Mass ...... V-2981 Xiaoquan Wang, K.T. Chan The Case of the Vibrating Superfractionator ...... V-2989 Adolf E. Blach Study on Generation Mechanism of Self-Excited Vibration in Cylindrical Grinding ...... V-2997 Yoshiaki Terumichi, Shinichi Ohno The Classification of Original Measure and Measurement Device Due to Their Sensitivity to Vibrations and Other Loads During Transportation ...... V-3005 Dimitrije Jankovic, Svetozar Jankovic Investigations of Microseismic Vibrations From Seismogeneous Sources as a Presage of Seismic Events ...... V-3015 T.Ho. Babayan, S. Karapetyan, H. Abrahamyan

21 Click here to view scanned manuscript ICSV5 Paper Abstract A Century of Shock Wave Dynamics Authors: Sir James Lighthill Volume 1, page 3, paper no. 129 Abstract: The recent three-volume history Twentieth Century Physics [1] includes my 118- page Chapter 10, Fluid Dynamics about a field where the 20th centurys first decade saw big breakthroughs in the analysis of nonlinear problems for which the physicists standard perturbation methods break down and which would later be named singular perturbation problems. Besides the 1904 elucidation of boundary-layer structure by Prandtl, these included the 1910 elucidation of shock-wave structure in complementary investigations by Rayleigh and by Taylor. Subsequent advances in shock wave dynamics brought crucial new discoveries on the structure and propagation of weak shocks, and also on shock-wave / boundary- layer interaction, both with major aeronautical implications; along with still harder investigations into the structure and propagation of strong shockwaves such as appear in explosions and implosions and also around spacecraft re-entering the earths atmosphere. It may, perhaps, be worth noting that questions which remain relatively simple for weak waves, like the nature of reflexion and diffraction by a solid body, raise formidable and intriguing difficulties for strong shock waves. In this introductory paper looking back over a century of shock wave dynamics, I highlight (i) key analytical approaches for both weak and strong shock waves, (ii) beautiful and effective optical methods for use in wind tunnels and shock tubes and (iii) powerful techniques for accurate shock capturing in computational fluid dynamics.

22 Click here to view scanned manuscript ICSV5 Paper Abstract Recent Developments in Acoustics and Vibration Authors: Malcolm J. Crocker, Auburn University, ( U.S.A.) Volume 1, page 27, paper no. 25 Abstract: In recent years there have been rapid advances in digital computers, the miniaturization of electronic circuits and in the development of new materials. In the acoustics and vibration fields, these advances have led to a continual increase in computational power and speed of analysis, improved acoustics and vibration transducers and instrumentation and better measurement techniques. In many cases the developments have been synergistic; new experimental knowledge has led to improved theoretical models and approaches and vice versa. Improved computers have allowed the development of a host of computer programs and increasing numbers have become available as commercial acoustics and vibration software. Of particular importance has been the development of numerical calculation schemes such as the finite element method (FEM) and the boundary element method (BEM) which have led to much improved predictive capabilities in many fields. Fields that have shown advances in recent years include: Aeroacoustics, Underwater Sound, Ultrasonics, Mechanical Vibrations, Noise Control, Ar- chitectural Acoustics, Physiological Acoustics, Speech Communication, Musical Acoustics, Bioacoustics, Acoustical Measurements and Instrumentation and Transducer Design. As examples, a few of these advances will be concisely summarized as follows: increased knowledge and use of Sonochemistry, new Computational Aeroacoustics techniques, improved Underwater Transducers and Sonar System design, use of Ultrasonics in Medical Diagnostics and Medical Imaging and for Therapeutic Effects and the use of Ultrasonics in Nondestructive Testing, Active Noise and Vibration Control including the use of PVDF and PZT as piezoelectric structural sensors and actuators, improved Architecural Acoustics Design, increased Cochlear Mechanics knowledge and the use of Cochlear implants, improved techniques for Speech Cod- ing and Recognition of Speech, improved Sound Intensity Measurements and their uses for Sound Power Determination and Noise Source Identification and Ranking, and better Digital Audio and Hearing Aid Transducer Design.

23 Click here to view scanned manuscript ICSV5 Paper Abstract Into the Physics of Rotor Aeroacoustics - Highlights of Recent European Helicopter Noise Research Authors: Hanno Heller, DLR, Institute of Design Aerodynamics, ( Germany) Volume 1, page 59, paper no. 81 Abstract: Significant advances in understanding helicopter noise have been made through several recent major European dedicated rotor aeroacoustics research projects. The availability of the German Dutch Wind Tunnel (DNW) allowed research on relatively large main rotor models (up to 40% full-scale). The simultaneous application of blade-mounted absolute pressure sensors to probe into the aeroacoustic source mechanisms, of advanced acoustic-data acquisition systems for radiated noise, and of sophisticated flow-visualisation/-measurement techniques (Laser Light Sheet, Laser Doppler Velocimetry) to study the interrelationship of rotor aerodynamics and blade dynamic response, has provided insight into the aeroacoustics of rotors. Towards controlling rotor noise, projects dealt with higher harmonic or individual blade control to affect blade vortex interaction. Much data served as benchmark information to advance theoretical rotor noise prediction for moderate tip speed conditions based on linearised potential flow methods or Euler methods combined with the acoustic analogy approach", and for high tip speed conditions based on Computational Fluid Dynamics and Kirchhoff approaches. This paper discusses several major European helicopter aeroacoustics research projects (e.g. the EU-initiated HELINOISE and HEL- ISHAPE projects, and the joint European-US HART project) to indicate recent relevant progress and how the findings provide guidance towards the ultimate objective - the quiet helicopter.

24 Click here to view scanned manuscript ICSV5 Paper Abstract Recent Advances in the Active Control of Structurally Radiated Sound Authors: Chris R. Fuller, Virginia Polytechnic Institute & State University, ( U.S.A.) Volume 1, page 103, paper no. 54 Abstract: Recent research and applications in the ﬁeld of Active Structural Acoustic Control (ASAC), a technique for reducing low frequency sound radiation from structures, are discussed. The paper overviews some new advances in the ASAC component and system areas of actuators, sensors, controllers, analysis and optimization. Recent commercial applications of ASAC as well as some promising new uses are brieﬂy outlined.

25 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Suppression Through Smart Damping Authors: Daniel J. Inman, Virginia Polytechnic Institute & State University, ( U.S.A.) Volume 1, page 115, paper no. 151 Abstract: This work examines the use of piezoceramic devices, as well as viscoelastic elements in various configurations as damping treatments to suppress unwanted vibrations in structural elements such as satellite components, bladed disk assemblies and circuit boards. The combining of the use of piezoelectric materials with viscoelastic damping treatments is a form of hybrid damping referred to here as smart damping. Here we examine various configurations for combining viscoelastic and piezoceramic damping treatments in view of the mechanics of layered media and in view of controllability considerations. The various designs and configurations studied are based on trying to take advantage of the best properties of passive damping treatments and of active damping provided by smart structures actuation. These materials allow the construction of unobtrusive sensors and actuators fully integrated into a structural system along with any viscoelastic material. One advantage of using piezoceramic elements combined with viscoelastic elements is the possibility of using the active component to compensate for the temperature and frequency dependence of a viscoelastic element rendering a treatment that is insensitive to these effects. Previous work in the area is presented which is followed by a discussion of modeling issues, design considerations and a summary. Several examples illustrate the usefulness of this approach for vibration suppression in structural components.

26 Click here to view scanned manuscript ICSV5 Paper Abstract Developments in Digital Analysis Techniques for Diag- nostics of Bearings and Gears Authors: R.B. Randall, University of New South Wales, ( Australia) Volume 1, page 133, paper no. 199 Abstract: For many years it has been recognised that so-called envelope analysis is a very powerful tool in the detection and particularly diagnosis of rolling element bearings. A recent quantitative study of the effects of masking signals has shown the benefits of performing the envelope analysis digitally, because of the better quality of filtering and the improved flexibility. This paper demonstrates the considerable enhancements which can be achieved by analysing the squared envelope signal, provided that the ratio of bearing to background signal can be made greater than unity, and discusses methods of achieving this by optimum bandpass filtering and self adaptive noise cancellation to remove masking by gear signals. Techniques are also discussed for dealing with very short signals, and varying signal paths suchas for planet bearings in epicyclic gearboxes. Developments are also proceeding in the field of gear diagnostics, made possible by the availability of new digital signal processing packages and for example direct downloading of vibration signals from a DAT recorder. An example is the increase in the application of time-frequency analysis techniques such as wavelet analysis and variants of the Wigner-Ville distribution. The paper discusses a number of techniques and compares the use of direct transmission error measurement with externally measured vibration signals.

27 Click here to view scanned manuscript ICSV5 Paper Abstract Hearing Protectors Authors: Samir N.Y. Gerges, Federal University of Santa Catarina, ( Brazil) Volume 1, page 151, paper no. 60 Abstract: This paper addresses the important practical issues of hearing protectors attenuation that are used in industry to protect workers from high levels of noise. Comments on the difficulties in the measurement attenuation of hearing protectors are discussed. A new work on the numerical modelling of the outer ear- canal is presented that considers the eardrum acoustic impedance and examines finite element (FEM) and infinite FEM for the quantification of the noise attenuation of the protector. In addition, the numerical model considers the geometry of the outer ear, outer ear-canal and the eardrum acoustic characteristics. The model can serve as a quick and low cost tool for the optimisation of a protector design and the investigation of the effect of different parameters such as protector insertion, effect of leakage, materials, and others on the protector noise attenuation.

28 Click here to view scanned manuscript ICSV5 Paper Abstract Industrialization of Active Control Technologies Authors: Christian Carme, Technofirst, ( France) Anne Montassier, Technofirst, ( France) Volume 1, page 173, paper no. 566 Abstract: Industrialization of active control technologies is a specific trade. This new technology is not completely controlled. Several specific competences are necessary. In this paper we present a synthesis on the limitation of active control technologies, advantages, application estate, development and industrialization’s tools. The second part of the document presents products using this technology.

29 Click here to view scanned manuscript ICSV5 Paper Abstract High-Performance Real-Time Computing Methods Authors: Osman Tokhi D.N. Ramos-Hernandez M.A. Hossain Volume 1, page 189, paper no. 228 Abstract: The performance demands in practical realisation of signal processing and control strategies has moti- vated a trend towards utilisation of complex algorithms. This, in turn, has resulted in a resurgence in the development of high-performance processors to make real-time implementation of such algorithms feasible in practice. However, due to inefficient mapping of algorithms on processors, to take account of the computing capabilities of processors in relation to the computing requirements of the application, such a goal can still be difficult to reach. This paper presents an investigation into the development of sequential and parallel computing methods for real-time signal processing and control. Several algorithms encountered in acoustics and vibration applications are considered. These are implemented on a number of high-performance processors including the TMS320C40 parallel digital signal processing device, the Intel i860 vector processor and the Inmos T805 transputer. A comparative assessment of the performance of the processors in implementing the algorithms, revealing the capabilities of the processors in relation to the nature of the algorithms, is presented. This is used as the basis of development of new performance metrics and task to processor mapping strategies for parallel architectures. The performance metrics and mapping strategies thus developed are verified by implementing the algorithms on a number of homogeneous and heterogeneous parallel architectures.

30 Click here to view scanned manuscript ICSV5 Paper Abstract An Adaptive Sound Intensity Control Algorithm For Ac- tive Control Of Transformer Noise Authors: Xiaojun Qiu, The University of Adelaide, ( Australia) Colin H. Hansen, The University of Adelaide, ( Australia) Volume 1, page 205, paper no. 562 Abstract: A frequency domain filtered-x type least mean active sound intensity adaptive control algorithm based on waveform synthesis is developed for active control of transformer noise. The algorithm is useful for providing global control of transformer noise by minimising the mean active sound intensities for the fundamental frequency and its harmonics in the near acoustic field of the transformer. Mean active sound intensity has been found to be the most effective near field acoustic error sensing strategy for active control of free field sound radiation. The algorithm adjusts the amplitude and phase of each tone to be controlled in the frequency domain and implements the waveform synthesis process in the time domain. The transfer function of the cancellation path is included in the algorithm so that it becomes a filtered-x type adaptive algorithm.

31 Click here to view scanned manuscript ICSV5 Paper Abstract Design of Curved Panel Sources for Active Control of Sound Radiated by Transformer Authors: Xun Li, The University of Adelaide, ( Australia) Colin H. Hansen, The University of Adelaide, ( Australia) Xiaojun Qiu, The University of Adelaide, ( Australia) Volume 1, page 213, paper no. 559 Abstract: Traditional means of controlling sound radiated by large electrical power transformers involve the construction of large, expensive ugly barriers or full enclosures which compromise the maintainability of the transformers. One promising alternative is to use active sound cancellation to reduce the noise. In this paper the work was concerned with the development of a resonant curved panel with a backing cavity which could be more effective, more efficient (regarding electrical power requirements) and more rugged than conventional loudspeakers. The reasons for using a curved panel rather than flat panel were twofold: first a curved panel is more easily excited by piezoelectric patch actuators because the bending vibration of the panel couples better with the extensional motion of the actuators; and second, it is not possible to adjust the resonance frequencies of the efficient modes of a flat panel so easily. An analytical model was developed to design a curved panel with backing cavity system having resonance frequencies of 100 Hz and 200 Hz for the 1,1 mode and 1,3 mode respectively. Of cause there are many possible geometric configurations which can achieve the desire result. An example configuration was designed using the analysis described in this paper and the result verified by finite element analysis (FEA). The panel was constructed, resonance frequencies were measured and sound radiation as a function of piezoelectric patch actuator excitation voltage was determined.

32 Click here to view scanned manuscript ICSV5 Paper Abstract A Filtered-X Adaptive Notch Filter With On-Line Cancel- lation Path Estimation Authors: A. Minguez, Universidad Politecnica de Madrid, ( Spain) Manuel Recuero, Universidad Politecnica de Madrid, ( Spain) Volume 1, page 223, paper no. 543 Abstract: This paper presents a simple adaptive algorithm based on the adaptive notch two-taps filter and the filtered-X LMS algorithm, to be used in active noise control applications. The system consists of two adaptive algorithms working together. One algorithm estimates the error path transfer function on-line and the other cancels a frequency narrowband of the residual signal. The convergence factors of the two adaptive algorithms determine the spectrum width of the cancellation and the stability of the control system. The adaptive filter used for estimating the error path has also two taps, it is only necessary to estimate the module and the phase at the center frequency of the cancellation bandwidth. The system can be generalized to a configuration of multiple cancellation frequency narrowbands and a multiple notch filter control system. This adaptive algorithm can be used in active noise control applications to cancel only frequency narrowbands and when it is not possible to get any reference signal.

33 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Implementation of Modal Filters for Acoustic Sensing of Sound Power Radiation Authors: Kym A. Burgemeister, Arup Acoustics, ( Australia) Scott D. Snyder, University of Adelaide, ( Australia) Volume 1, page 231, paper no. 487 Abstract: Modal filtering has emerged as a valuable technique for the measurement of significant system parameters, such as sound power, for use in active noise and vibration control. By providing a , measure of only a few of the most significant parameters, reductions in the complexity of the adaptive control system can be achieved. The physical implementation of such a modal filter is discussed for a system for measurement of sound power radiated from a simply supported rectangular panel. The effect of frequency normalisation of the modal filter on the amount of attenuation that maybe achieved is examined. Frequency normalisation allows simplifications to the modal filter system with little degradation to resultant attenuation levels, although the effective bandwidth of the filter system is reduced.

34 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Structural Radiation Using Wavenum- ber Spectrum Measurements Authors: Scott D. Sommerfeldt, Brigham Young University, ( U.S.A.) Brian L. Scott, The Pennsylvania State University, ( U.S.A.) Volume 1, page 239, paper no. 327 Abstract: There is a broad class of active control problems involving control of the acoustic power radiated from a vibrating structure. For many of these applications, it is desirable to implement the control using structural sensors, as opposed to far-field pressure sensors. It is known that the acoustic radiation cor- responds to the supersonic wavenumber components of the vibration. Previous work by the authors has demonstrated that one can design distributed sensors that provide a direct measurement of the radiated power using a spatial Fourier transform of the sensor measurements. The sensors have been much more effective in predicting the radiated power than using a similar number of point sensors on the structure. The work reported here uses this wavenumber in formation as the basis for an active control system that attenuates the far-field radiation by means of minimizing the supersonic wavenumber components. The numerical results presented compare and contrast the far-field results obtained using this active control approach with results obtained when simply minimizing the vibration signal at the discrete locations. The results indicate that significant far-field control can be achieved by directly measuring the supersonic wavenumber vibration and minimizing that vibration, while ignoring the non-radiating subsonic wavenumber components.

35 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Effect Of Wall-Axial Wave Component on the Active Control of Water-Borne Noise in Steel Pipes Authors: Michael Podlesak, Defence Science and Technology Organisation, ( Australia) Volume 1, page 247, paper no. 192 Abstract: Active control of low frequency pump noise in water-filled pipes is being developed at AMRL for acoustic signature control on maritime platforms. The present approach is based on separate fluid and wall-axial wave control with collocated control sources. One of the main problems encountered in the design of suitable control sources is their operating effectiveness over a large range of internal hydrostatic pressures. A prototype of a fluid-wave control source has been built which is able to provide some control at low frequencies in a steel pipe system. However, at higher frequencies, the control is considerably compromised through a mechanism believed to be linked to flanking via wall-axial wave components. This paper reports the results of experiments designed to study the effect of flanking with the ultimate aim of establishing requirements for the design of a complementary source for the control of wall-axial waves.

36 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Machinery Noise in a Marine Environ- ment - Lessons Learned Authors: Ronnie C N Leung, Defence Evaluation and Research Agency, ( U.K.) Volume 1, page 255, paper no. 127 Abstract: A research programme to investigate the feasibility of using active control systems to oontrol the radiated noise of a naval platform due to the on-board machinery was first set up in the late 1970s at The Defence Evaluation and Research Agency. The programme covers the development of control algorithms, development of the hardware for the controller, a trial on a naval platform, analysis of the trial results and the development of several actuators for different transmission paths. This paper presents the experience and lessons learned from the programme. The programme demonstrated that active control of tonals associated with a machine on board a naval platform is feasible. The key to success is a clear understanding of the interactions between all the possible transmission paths from the noise source. This applies to both passive and active controls.The major obstacles to wider application of active control techniques are a lack of suitable off-the-shelf actuators and their costs.

37 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Cabin Noise in Aircraft - Lessons Learned? Authors: Chris R. Fuller, Virginia Polytechnic Institute & State University, ( U.S.A.) Volume 1, page 263, paper no. 53 Abstract: The evolution of active systems applied to the reduction of aircraft cabin noise is studied. The main objective is to establish whether there are any signiﬁcant lessons relative to the general use and com- mercialization of active noise and vibration systems.

38 Click here to view scanned manuscript ICSV5 Paper Abstract Use of a Water Impedance Tube to Evaluate the Perfor- mance of a Smart Skin Piston Element Authors: Peter D Dean, Lockheed Martin Missiles and Space Co, ( U.S.A.) Volume 1, page 271, paper no. 567 Abstract: The concept of a smart skin embodies the philosophy of a multilayer structure that includes sensing elements, actuation elements and a controller. Such an embedded system has been developed for under water vehicle applications where the objective is the control of both near and far ﬁeld noise. Acous- tic/structural characterization is a necessary part of optimal design, however the simulation models available for prediction of the acoustic performance of complex structures such as these are inadequate. The transfer functions necessary for control of the piston actuator elements in the array skin are derived from direct experiment using a Water Impedance Tube. This paper describes the experimental system used, the analysis performed, transfer function results and their implications in active underwater acoustic control systems.

39 Click here to view scanned manuscript ICSV5 Paper Abstract Feedback Control of Noise in a Room Authors: Chaoying Bao, University of Western Australia, ( Australia) R. Paurobally, The University of Western Australia, ( Australia) Jie Pan, The University of Western Australia, ( Australia) Volume 1, page 279, paper no. 530 Abstract: Active noise control technology is an attractive solution for attenuation of low frequency noise in enclosures. In terms of control strategies, feedforward control has often been used. While feedforward control has many advantages, its success relies on the availability of causal reference signals which have to be highly correlated to the noise to be cancelled. For some applications such as attenuation of random noise in oﬃce spaces or vehicle cabins, such reference signals are either not available or very expensive to obtain. In these situations, feedback control can be an alternative solution. In this paper, a single channel feedback control system for global noise attenuation in a room is presented. The controller is designed based on the compensation ﬁlter approach of the classical control theory. Experimental results are also presented.

40 Click here to view scanned manuscript ICSV5 Paper Abstract Active Equalisation of the Sound Field in an Extended Region of a Room Authors: Arturo Orozco-Santillan, Technical University of Denmark, ( Denmark) Volume 1, page 287, paper no. 494 Abstract: A theoretical study of spatial sound equalisation in an extended region in a room has been carried out. The purpose is to reproduce sound without significant spatial fluctuations and to minimise the spectral colouration at low frequencies in a specified region of the room. The problem is first studied by means of an idealised frequency domain model. The analysis is based on the calculation of the complex source strengths that minimise the difference between the actual sound pressure and the desired sound pressure in the listening area. Results in relation to the position of the sources, the frequency range, and the size and location of the listening area are presented. However, the frequency-domain approach results in non-causal impulse responses that can be realised only at the expense of a delay. Therefore, this analysis is supplemented with a study of the equalisation carried out in the time domain. Here, a solution constrained to causality is determined. The duration of the impulse response should be minimised as well in order to avoid echos, which are undesirable in the reproduction of transient signals. This causality-constrained equalisation is compared with the optimal solution obtained in the frequency domain.

41 Click here to view scanned manuscript ICSV5 Paper Abstract A Traveling Wave Approach to Active Noise Control in Ducts Authors: Jing Yuan, The Hong Kong Polytechnic University, ( Hong Kong) K.Y. Fung, The Hong Kong Polytechnic University, ( Hong Kong) Volume 1, page 295, paper no. 341 Abstract: Feedforward cancellation is an effective approach to active noise control (ANC) in ducts. An ANC system synthesizes an anti-sound according to a reference signal measured between the noise source and the anti-sound. Its objective is to avoid the potential feedback of the anti-sound while canceling the directional propagation of the noise. An important advantage of feedforward ANC systems is their ability to improve performance by adaptation. The convergence of the adaptation depends on the transfer function of the error channel, which is not available conveniently. To identify the error channel, a pseudo random signal is added to excite the impulse response of the error channel. The system must separate the impulse response from the error signal when both share the same frequency range. This paper presents a new approach to feedfoward ANC in ducts. It places an additional sensor near the primary error sensor, and separates the traveling wave components from the pressure signals. The separation of traveling waves simplifies the adaptation and the problems associated with transfer functions of duct sections, The transfer functions of the error channel, loudspeaker and power amplifier can easily be identified without the annoying pseudo random signal.

42 Click here to view scanned manuscript ICSV5 Paper Abstract Study of Active Noise Control by Using Structural Acous- tic Coupled Analysis Authors: Shozo Kawamura, Kobe University, ( Japan) Atsushi Morita, Kobe University, ( Japan) Takuzo Iwatsubo, Kobe University, ( Japan) Koki Shiohata, Hitachi Ltd., ( Japan) Volume 1, page 303, paper no. 307 Abstract: The active noise control, which is effective for low frequency band, has been developed, When the high control performance would be achieved in the enclosed cavity, it is necessary to measure the sound pressure at many measuring points in the cavity. But it is hard to set many sensors in the cavity because of the lack of space or cost problem. In this paper, an active noise control method is proposed for the steady state acoustic field. The fundamental idea is that the unknown sound pressure in the cavity are estimated by using structural-acoustic coupled analysis, that is, the sound pressure are virtually measured at many points. At first, the active noise control method is formulated based on the feedforward control theory. Next, the identification method of the sound pressure in the cavity, which are the cost function of the feedforward control, is formulated by using the structural-acoustic coupled analysis method. As the numerical example, the rectangular prism model is taken up, and the active noise control in the model is simulated by using the proposed method. As the result, it is shown that the proposed method is effect in the numerical simulation.

43 Click here to view scanned manuscript ICSV5 Paper Abstract Strategies for Active Control of Sound Transmitted Through a Double-Panel Partition Using Distributed Actuators and Sensors Authors: Xia Pan Trevor J Sutton S.J. Elliott Volume 1, page 311, paper no. 304 Abstract: The paper considers the active control of harmonic and random sound transmitted through a double-leaf partition using a single distributed actuator and a single distributed sensor. The double-leaf partition consists of a pair of small plates (300x380 mm, separated by a 100 mm air-gap). An actuator made up of shaped, distributed PVDF offers the possibility of controlling the volume velocity of a plate without giving rise to control spillover. The sensor consists of a matched PVDF sensor to detect volume velocity. For harmonic excitation with the actuator attached to either panel, substantial reductions in the transmitted sound power are possible up to around 350 Hz. A radiation mode analysis of the panels shows that the double-leaf construction provides good passive attenuation of the first radiation mode at high frequencies, so that inefficiently radiating even modes of the radiating panel make a dominant contribution to the radiated sound power. For the random excitation, an internal model control scheme is outlined for the double-panel system in which the transmission of random sound is controlled without the need for a reference signal. Cancellation of volume velocity with the distributed actuator provides reduction in random sound transmission up to 100 Hz.

44 Click here to view scanned manuscript ICSV5 Paper Abstract Delayless Subband Echo Cancellation Authors: Sven Nordholm, University of Karlskrona/Ronneby, ( Sweden) Joergen Nordberg, University of Karlskrona/Ronneby, ( Sweden) Volume 1, page 319, paper no. 277 Abstract: Increased use of mobile telephones in cars has created a greater demand for hands-free in-car installa- tions. The advantages of hands-free telephones are safety and convenience. The disadvantages are poor sound quality and acoustic feedback of the far-end speaker. The filtering required to obtain a similar sound quality as for hand held telephony must suppress the loudspeaker, as well as background noise and room reverberation, without causing severe speech distortion. This paper deals with the acoustic echo feedback problem. The acoustic feedback problem is also a reality in applications such as video con- ferencing and hands-free office telephones. All these applications has created a demand for high-quality acoustic echo cancellation. In order to track variations in the acoustic channel the echo cancellation is made adaptive. The acoustic channel has typically a long impulse response in the order of 100ms. Typical lengths of adaptive FIR-filters are 500-1500 taps assuming a 8 kHz sampling frequency. A subband echo canceller gives several advantages compared to a full-band echo canceller such as: 1. The computational burden is essentially reduced by the number of subbands due to decimation. 2. A faster convergence since the spectral dynamic range in each subband will be less. 3. The signal controlled adaptation can be performed in each subband individually, hence, enhanced performance. 4. A well separated structure for parallel implementation is obtained. This paper presents an implementation and improvement of a delayless subband adaptive filter presented by Morgan and Thi. This adaptive filter structure employs the benefits of adaptive subband filtering, but does not suffer from the inherent delay usually found in subband schemes. This is due to the fact that the FIR filtering is performed without delay directly on the full-band signal. The following improvements are presented in this paper: 1. Improved filter bank design which gives possibilities to improve the convergence rate. 2. A signal detection scheme operating in each subband improving the convergence rate when using signal with large spectral dynamics, i.e. a speech signal.The study shows a possible echo suppression of about 30 dB and also a more rapid convergence compared to a fullband LMS-filter.

45 Click here to view scanned manuscript ICSV5 Paper Abstract A New Active Headset for a Helicopter Application. Authors: Sven Johansson, University of Karlskrona/Ronneby, ( Sweden) Mathias Winberg, University of Karlskrona/Ronneby, ( Sweden) Thomas Lago, University of Karlskrona/Ronneby, ( Sweden) Ingvar Claesson, University of Karlskrona/Ronneby, ( Sweden) Volume 1, page 327, paper no. 240 Abstract: In helicopters the low frequency noise generated by the rotors and engines often masks and jeopardizes safe communication. Additionally, pilots are likely to suffer from hearing damages due to the higher sound levels in the headset produced when compens In many Active Noise Control (ANC) applications the primary noise field is either periodic or broadband which simplifies the choice of algorithm.Typically, noise up to 100 Hz is dominated by tones and in the range from 100Hz to 400 Hz the noise chara a digital feedforward controller and an analog feedback controller is employed. The feedforward controller is tachometer based and reduces the tonal components, while the feedback controller attenuates the more broadband noise. In this paper, a combination of these two techniques is evaluated on real data.

46 Click here to view scanned manuscript ICSV5 Paper Abstract New Approaches to Active Noise Control - Theory and Experimental Results Authors: Marek Pawelczyk, Institute of Automation, ( Poland) Volume 1, page 335, paper no. 188 Abstract: The objective of the paper is to present and examine new concepts of noise cancellation algorithms. At the beginning, feedforward FIR filters are analysed in terms of stability. Then an algorithm named Normalised-W LMS, increasing speed of convergence and decreasing steady state error is proposed. Next, two algorithms based on physical - not automatic - approach named PHS (PHase Shifter implemented in a discrete way) and PHS2 are thoroughly explained. They are suitable for narrowband sounds with spectrum concentrated around one frequency. Having minimum number of parameters - at least an order less then for other feedforward solutions - guarantee better attenuation effects: significantly extend attenuation band and ensure attenuation up to 60 [dB] (40 [dB] in the range between 100 [Hz] and 5 [kHz]). The idea of PHS and PHS2 was extended to broadband noise and was named PHS - banks. Each bank consists of a band-pass filter and a PHS. A PHS can cover signal having spectrum not wider than about 40 [Hz], so the filters should be properly designed. Described algorithm is able to attenuate any sound in very wide band up to 40 [dB]. Investigations performed with various sampling frequencies (4, 2, 1, 0.5 [kHz]) and feedforward control show that for each sampling frequency obtained attenuation bands are adjacent or slightly overlapped and usually octave. Thus, multirate signal processing technique was successfully adopted. Feedback structures were also considered. Modified Minimum Variance Controller was proposed and tested. Finally, hybrid control algorithm integrating feedforward and feedback techniques by an arbitrary system was originally developed. This assures satisfactory attenuation in the whole band justified by plant coherence function.

47 Click here to view scanned manuscript ICSV5 Paper Abstract Industrial Applications of the Active Seat ANCAS Authors: Christian Carme, Technoﬁrst, ( France) G. Valentin, Dassault Electronique, ( France) Volume 1, page 343, paper no. 12 Abstract: In 1995, we presented the ﬁrst results about the Active seat ANCAS (R), jointly developed by Dassault Electronique and TechnoFirst. Strongly concerned by progressing to an improved product, TechnoFirst has carried on research in order to enlarge the universalit y of this technology, either in aeronautic or automotive applications. Furthermore, the behaviour of the ANCAS (R) when used in a set of active seats, has been invcstigated. This paper contains the work recently performed experimental results and several industrialapplications. on the ANCAS (R) including experimental results and several industrial applications.

48 Click here to view scanned manuscript ICSV5 Paper Abstract Active Double Glazing: the Solution is the Transducer Authors: Christian Carme, Technofirst, ( France) Anne Montassier, Technofirst, ( France) M. Rehfeld, Saint Gobain Vitrage, ( France) Volume 1, page 351, paper no. 11 Abstract: Looking at the increasing request concerning sound insulation in building, Technofirst (R) and Saint- Gobain-Vitragc propose an active double-glazing window. In this partnership TechnoFirst (R)brings its experience in active control system, The product will be characterized by a global insulation never obtained. It deals with anacoustic treatment of the air volume. Modelisations have been done and show the contribution of each acoustic mode. The experiments have confirmed these informations. This publication shows first results obtained with a prototype. The electroacoustic system which allows this treatment can be fitted into the width of the air volume.

49 Click here to view scanned manuscript ICSV5 Paper Abstract ANC Headset: the Second Generation Authors: Christian Carme, Technofirst, ( France) David Derrien, Technofirst, ( France) Pierre De Man, Technofirst, ( France) Volume 1, page 359, paper no. 10 Abstract: In 1981, we started a development of Active Noise Control headsets. 1 The results of these works were presented at EUROMECH 213 in 1986 and INTERNOISE 1988. The new filtering developed for this technology was able to improve the bandwidth and the level ofnoise reduction. Today, we have continued the development and the purpose of this paper is to present a headset with a feedback control which avoid an increase of noise in high freqencies when Active Noise Control is on. The second point presented in this paper is an improvernent of speech transmission when ANC is on. With this new solution, the speech transmission has no more interuptions due to the vibration of the headset with ANC switched on. In that way, this headset may be weared in a jolting environment as a vehicule. These technical progresses allowed the realization of a new serie of headsets inorder to meet all industrialists and general publics requirements.

50 Click here to view scanned manuscript ICSV5 Paper Abstract A Solution for ANC Treatment in Flow Noise for Very Low Frequencies: a Product Named ACTA Authors: Christian Carme, Technofirst, ( France) Virginie Delemotte, Technofirst, ( France) Pierre De Man, Technofirst, ( France) Volume 1, page 367, paper no. 9 Abstract: Because of the increasing demand about sound insulation in building, tradesmen have today to find and apply new solutions to reduce noise. With this aim in view, Aldes Aeraulique company, French leader in ventilation, and TechnoFirst company decided to develop an active muffler in partnership. TechnoFirst, specialized in active noise and vibration control, brings its know-how for the development and the industrialization of systems based on this new technology. From research works realized by the "Laboratoirc de Mecanique et dAcoustique", TechnoFirst has developed a single system which will be cornpatible with all the configurations of the products proposed by Aldes. Technical choices had been made to obtain optimum conditions about acoustic performances (great noise attenuation), dimensions and negligeable charge loss. Today, Aldes and TechnoFirst are in position to propose a muffler on the ventilation market, eombining passive and active effects. The acoustic attenuation of this device is greater than the one obtained with a standard waffle muffler, with less charge loss introducing. This single system can be installed anywhere in the duct whatever diameter.

51 Click here to view scanned manuscript ICSV5 Paper Abstract Hybrid Controller: Theory & Product Authors: Christian Carme, Technofirst, ( France) David Derrien, Technofirst, ( France) Pierre De Man, Technofirst, ( France) Volume 1, page 375, paper no. 8 Abstract: NOVACS(TM) has been a complete success, This pioneer multichannel controller commercialized since 1989 is based on a specific philosophy : providing to an active control neophyte the tools and means in order to design serious experimentations. NOVACS(TM) is equiped with a standard digital signal and may process till 11 input signals and 8 output signals. NOVACS (TM) allows the developments of active control system closed to industrial products and the rapid characterization of the main problems to solve avoiding to physicist to be snowed under specific electronic computing. In this new NOVACS (TM) version, TechnoFirst (R) company proposes its last innovation which has been patented in 1995 and which is now available in its products : the hybrid control. Hybridcontrol / combines the advantages of feedforward and feedback control without their respective drawbacks. In this paper we make the comparison between this new technology and the two classical ones. It will appear that TechnoFirst has defined a new way to design active noise and vibration control system.

52 Click here to view scanned manuscript ICSV5 Paper Abstract Characterisation of Piezoelectric and Electrostrictive Ma- terials for Acoustic Transducers: I. Resonance Methods Authors: Binu K. Mukherjee, Royal Military College of Canada, ( Canada) S. Sherrit, Royal Military College of Canada, ( Canada) Volume 1, page 385, paper no. 517 Abstract: Piezoelectric transducers are frequently used as acoustic sensors and projectors as well as in active methods of vibration control. Their proper utilisation requires a good understanding of their non- lin- ear properties and of the dielectric, mechanical and piezoelectric losses in the material. Besides, new computer codes are being developed for the modelling of piezoelectric materials and transducers and these are precise enough to require accurate material constants. The complex impedance of piezoelectric resonators of different geometries can be analysed around their resonances to determine the dielectric, elastic and piezoelectric coefficients as complex constants to take account of all the losses in these materials. The impedance curves may be measured as a function of applied dc voltage in order to determine the field dependence of the material constants. By analysing the fundamental and higher resonances, the dispersion in the material constants can be studied and the real and imaginary parts of the constants may be described by frequency dependent polynomials. A new equivalent circuit for the material takes account of all the losses. We gratefully acknowledge funding support from the Defence Research Estab- lishment Atlantic, Canada, and the Office of Naval Research, USA through the Naval Undersea Warfare Centre, Newport, USA.

53 Click here to view scanned manuscript ICSV5 Paper Abstract Characterisation of Piezoelectric and electrostrictive Ma- terials for Acoustic Transducers: II. Quasistatic Meth- ods Authors: Binu K. Mukherjee, Royal Military College of Canada, ( Canada) S. Sherrit, Royal Military College of Canada, ( Canada) Volume 1, page 395, paper no. 518 Abstract: Piezoelectric transducers are frequently used as acoustic sensors and projectors as well as in active methods of vibration control. Their proper utilisation requires a good understanding of the nonlinear properties of the material. Quasistatic experiments have been developed to determine the dependence of the more important material constants on the temperature and on the levels of voltage and stress applied singly or simultaneously to the material. The response time of the piezoelectric eﬀect has been studied and it has been found that the observations can be understood by assuming that the domain wall movements in the material are governed by a distribution of activation energies. More recently, high strain electrostrictive materials have been developed and these are inherently non-linear. Many of the above experiments can be used to characterise these materials as well. We gratefully acknowledge funding support from the Defence Research Establishment Atlantic, Canada, and the Oﬃce of Naval Re- search, USA through the Naval Undersea Warfare Centre, Newport, USA.

54 Click here to view scanned manuscript ICSV5 Paper Abstract Pole-Zero Assignment of Vibratory System Authors: Yitshak M. Ram, University of Adelaide, ( Australia) Volume 1, page 405, paper no. 516 Abstract: Recent results associated with simultaneous assignment of poles and zeros by state feedback control will be presented. It will be shown that the poles and some zeros of a vibratory system maybe assigned by choosing the position vector and the control force. This objective can be achieved with partial knowledge of the system, where the high frequency modal date and the damping matrix may be considered unknown. An example demonstrating the results will be given.

55 Click here to view scanned manuscript ICSV5 Paper Abstract Modal Filtering and Control of a Plate Using One-Dimen- sional PVDF Film Sensors Authors: Nobuo Tanaka, Mechanical Engineering Laboratory, ( Japan) Yoshihiro Kikushima, Mechanical Engineering Laboratory, ( Japan) Volume 1, page 413, paper no. 391 Abstract: This paper deals with distributed parameter sensors designed with a view to extracting a vibration mode. Compared to conventional point-type sensors such as acceleration pickups, displacement sensors etc., the distributed parameter sensors have many benefits provided that they are properly designed. First, this paper overviews a conventional modal filter designed by use of point sensors, and enumerates the problems it involves. To overcome the drawbacks of the point sensor based modal filtering, a novel modal filtering technique based upon a PVDF film sensor, a distributed parameter sensor, is proposed. Two-dimensional modal filters are discussed, and then, by taking into consideration a practicability of the sensors, a design procedure of one-dimensional modal filters is presented; the number, location and shaping of the one dimensional sensors are clarified. Finally, an experiment is conducted, showing the capability of the distributed parameter modal filtering.

56 Click here to view scanned manuscript ICSV5 Paper Abstract Finite Element Analysis of Active Vibration Isolation Authors: Carl Q. Howard, University of Adelaide, ( Australia) Colin H. Hansen, The University of Adelaide, ( Australia) Volume 1, page 421, paper no. 351 Abstract: Finite element analysis was used to predict the power transmission from an actively isolated vibrating rigid mass to a simply supported beam. Vibrational power transmission was used as the cost function to be minimised. The work demonstrated that neglect of power transmission due to moments in experimental work is the reason why negative power transmission in the vertical direction at some frequencies has been reported in the literature. Simulations show that under active control when power transmission in the vertical direction is used as a cost function to be minimised, the overall vibration isolation performance of the active isolator can be worse than without control.

57 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Nonlinear Vibration in a Flexible Can- tilever Beam Authors: Thanh Lan Vu, University of Western Australia, ( Australia) Jie Pan, The University of Western Australia, ( Australia) Volume 1, page 429, paper no. 551 Abstract: The aim of this paper is firstly to address the consequences of the nonlinear interactions between higher order modes and the first order mode of a flexible cantilever beam. The tested cantilever beam ex- hibited numerous nonlinear phenomena that are commonly observed in many flexible structures. The experimental results have shown that active control of the nonlinear vibration in a flexible structure is effective. Secondly, the paper describes how the nonlinear vibration in the cantilever beam was cancelled using a digital feedback controller implemented in a dSpace TM Digital Signal Processing board. It has been demonstrated experimentally that the on-line feedback controller was capable of cancelling the low frequency vibration generated in the flexible cantilever beam due to nonlinear interaction between the modes of the beam. This control scheme has considerable potential for cancelling of nonlinear vibration in large structures such as aircraft, ships, etc. in order to reduce stress and fatigue of these structures.

58 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Flexural Vibrations Using a Hybrid Mode/Wave Approach Authors: C. Mei, The University of Auckland, ( New Zealand) Brian R. Mace, The University of Auckland, ( New Zealand) R.W. Jones, The University of Auckland, ( New Zealand) Volume 1, page 437, paper no. 417 Abstract: Modal approaches to active vibration control, such as independent modal state control (lMSC), suffer difficulties especially at higher frequencies. These arise due to robustness considerations in the presence of unmodelled and uncontrolled (since the modal properties a structure at higher frequencies are normally not known accurately) and from increasing controller complexity (due to the large number of of modes which need to be controlled at higher frequencies). Wave-based methods offer advantages at these higher frequencies. This paper describes a hybrid approach with specific application to the control of flexural vibrations of a beam. Velocity feedback control is applied to the system to add damping. This is designed using a wave-based approach to optimise energy absorption at a particular frequency. The modes of the controlled structure are now different to those of the uncontrolled structure and from these IMSC is designed to provide low frequency modal control. Numerical results are presented. The effects of controller location and digital implementation issues are discussed.

59 Click here to view scanned manuscript ICSV5 Paper Abstract Control of Structure-Borne Noise Transmission Using Electro-Rheological Fluid Inserts Authors: N.R. Harland, The University of Auckland, ( New Zealand) Brian R. Mace, The University of Auckland, ( New Zealand) R.W. Jones, The University of Auckland, ( New Zealand) Volume 1, page 445, paper no. 416 Abstract: The shear modulus and damping loss factor of electro-rheological (ER) fluids vary when the fluid is exposed to an electric field. This behaviour can be exploited to engineer smart structures with controllable dynamic properties. This paper describes one example of such a system. The intention is to control the transmission of structure-borne sound through a structural member such as a beam. This is achieved by inserting a length of a composite ER beam, comprising two elastic outer Iayers between which is sandwiched a layer of ER fluid, into the otherwise uniform beam. A voltage is applied across the outer layers of the ER beam, hence enabling the stiffness and loss factor of the composite beam to be altered. This in turn alters the wavenumbers and wave transmission characteristics of the structure. In broad terms, waves propagate along the waveguide and suffer reflections at the junctions between the beam and the ER fluid beam. Expressions for the power transmitted through the beam/ER beam/beam combination are given and numerical results are presented. In general the power is minimum at certain frequencies which depend primarily on the wavenumbers of the ER beam. In the presence of narrow-band structure- borne noise therefore the structure can be tuned by controlling the applied voltage in such a way as to minimise the transmitted power.

60 Click here to view scanned manuscript ICSV5 Paper Abstract Practical Realisation Issues In Adaptive Active Vibra- tion Control Authors: M.A. Hossain Osman Tokhi Volume 1, page 453, paper no. 360 Abstract: This paper presents an investigation into practical real-time realisation issues of active vibration control (AVC) systems. An adaptive active control system is considered. The control strategy is realised for a cantilever beam system in transverse vibration. The unwanted vibrations in the structure are assumed to be due to a single point disturbance of broadband nature. An AVC system is designed on the basis of optimum cancellation of broadband vibration at an observation point along the beam. Practi- cal issues related to the design and implementation of the system are high-lighted and discussed. An adaptive algorithm consisting of a simulation, control and identiﬁcation processes is developed. This is implemented on a number of computing domains involving high-performance reduced instruction set computer (RISC) processors and digital signal processing (DSP) devices. A comparison of the results of the implementations, on the basis of real-time computation performance, is made to establish merits of development of fast processing methods in real-time active control applications.

61 Click here to view scanned manuscript ICSV5 Paper Abstract Genetic Algorithms for Active Vibration Control Authors: M.A. Hossain Osman Tokhi Volume 1, page 461, paper no. 359 Abstract: This paper presents an investigation into the development of an active vibration control (AVC) system using genetic algorithms (GAs). During the last two decades, a substantial amount of research work has been carried out using GAs in various disciplines. Although GAs have gained popularity as parallel, global search techniques, their use in the area of active control is limited. This investigation attempts to develop evolutionary techniques utilising GAs for AVC applications. A ﬂexible beam system in transverse vibration is considered in this investigation. The unwanted vibrations in the structure are assumed to be due to a single point disturbance of broadband nature. A multi-source adaptive AVC strategy is adopted for optimum cancellation of broadband vibration along the beam. This incorporates an online controller design and implementation strategy. Genetic algorithms are used for estimation of the adaptive controller characteristics. The AVC algorithm thus developed is implemented and simulation results verifying its performance in the suppression of broadband vibration along the beam presented and discussed.

62 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Optimal Control of a Space Robot by the Nonholonomic Structure Authors: Koichi Matsuda, Kyushu University, ( Japan) Yoichi Kanemitsu, Kyushu University, ( Japan) Shinya Kijimoto, Kyushu University, ( Japan) Volume 1, page 469, paper no. 300 Abstract: Owing to the nonholonomic structure, a free-flying space robot can reorient its attitude only by actuating the manipulators. We formulate the approach to plan the optimal path of the manipulator movement to achieve such reorientation. This formulation has been done as an optimal control problem in a more general way than that of the problem to have been solved so far. That is, the approach can afford to solve the case where the initial and final posture of the manipulators are different and where the optimal solution is not a smooth and continuous function of time. The optimal control problem is converted via discretization with high-order integration methods into a finite dimensional problem and solved by the periodically preconditioned conjugate gradient-restoration algorithm.

63 Click here to view scanned manuscript ICSV5 Paper Abstract AVIIS, Active Vibration Isolation in Ships Authors: Thomas Lago, University of Karlskrona/Ronneby, ( Sweden) Mathias Winberg, University of Karlskrona/Ronneby, ( Sweden) Sven Johansson, University of Karlskrona/Ronneby, ( Sweden) Volume 1, page 477, paper no. 298 Abstract: Engine induced sound and vibration levels in boats for professional and leisure use is in many cases unacceptably high in term of comfort and the environment. Classical methods for passive treatment are normally less effective due to the low frequency content and often leads to an increase in weight. This contradicts the requirements for lower weight for increased speed. More efficient vibration damping methods must therefore be found. With active engine mounts, it is possible to achieve a decrease in the vibrations even when the hull is not very stiff. This is especially important in marine applications since the engines are mounted on weak and light structures. The AVIIS project aims at investigating the effects of a combined passive/active engine mount for use in boats. A Storebro 36 Royal Cruiser with two Volvo Penta engines has been used in the project. Four different approaches have been appraised, the results of which are presented here: 1. passive engine mounts, with and without thrust bearings, 2. optimized passive engine mounts, 3. passive engine mounts, rigidly mounted, 4. A combined active/passive engine mount. This paper reports the key data from the measurements and how the different primary sources have been estimated from the analysis. This analysis has then been used to select the ANVC approach.

64 Click here to view scanned manuscript ICSV5 Paper Abstract Modelling and Control of a Two Degree of Freedom Dy- namic Absorber Using Shape Memory Actuator Authors: P.K. Boominathan, Indian Institute of Technology, ( India) Y.G. Srinivasa, Indian Institute of Technology, ( India) M. Singaperumal, Indian Institute of Technology, ( India) Volume 1, page 485, paper no. 263 Abstract: Active vibration control using shape memory actuator is utilised to make a two degree of freedom dynamic absorber and demonstrate its eﬀectiveness in vibration suppression. A two degree of freedom spring-mass system interconnected by shape memory wires

65 Click here to view scanned manuscript ICSV5 Paper Abstract Neuro-Active Noise Control Using A Decoupled Linear/- Nonlinear System Approach Authors: Osman Tokhi R. Wood Volume 1, page 493, paper no. 227 Abstract: This paper presents an investigation into the development of an intelligent neuro-active noise control strategy which accounts for both linear and nonlinear dynamics of the system. Multi-layered perceptron neural networks with a backpropagation learning algorithm and radial basis function neural networks with an orthogonal forward regression algorithm are considered in both the modelling and control con- texts. A feedforward active noise control (ANC) structure is considered for optimum cancellation of broadband noise in a three-dimensional propagation medium. An on-line adaptation and training mechanism allowing a neural network architecture to characterise the optimal linear controller and nonlinear system dynamics within the ANC system is developed. The neuro-adaptive ANC algorithm thus developed is implemented within a free-ﬁeld environment and simulation results verifying its performance in the cancellation of broadband noise are presented and discussed.

66 Click here to view scanned manuscript ICSV5 Paper Abstract Active Control of Machine-Tool Vibration in a Lathe Authors: Ingvar Claesson, University of Karlskrona/Ronneby, ( Sweden) L. Hakansson, Lund University, ( Sweden) Volume 1, page 501, paper no. 22 Abstract: In the turning operation the relative dynamic motion between cutting tool and workpiece, or vibration is a frequent problem, which affects the result of the machining, in particular the surface finish. The tool life is also influenced by the vibrations. When the working environment is considered, noise is frequently introduced by dynamic motion between the cutting tool and the workpiece. By proper machine design, e.g. improved stiffness of the machine structure, the problem of relative dynamic motion between cutting tool and workpiece may be partially solved. However, by active control of machine-tool vibration, a further reduction of the dynamic motion between cutting tool and workpiece can be achieved. It was found that adaptive feedback control based on the filtered-x LMS-algorithm enables a reduction of the vibration with up to 40 dB at 1.5 kHz and simultaneously with approximately 40 dB at 3 kHz. A significant improvement of the workpiece surface was observed and a substantial improvement of the acoustic noise level was obtained with adaptive control.

67 Click here to view scanned manuscript ICSV5 Paper Abstract The Role of the Feedback Phenomenon in many Aeroa- coustics Problems of Current Interest Authors: Krishnan K. Ahuja, Georgia Institute of Technology, ( U.S.A.) Volume 2, page 513, paper no. 537 Abstract: Feedback phenomenon resulting in acoustic resonance is very common in a range of aeroacoustics problems of current interest. Screech in shock containing jets, cavity noise, edgetones, jet/collector interactions and howling of ejectors are but a few examples. In most of these problems involving shear layers, there is a match between the frequencies of sound and the most-preferred instability waves that are excited by the sound impinging at the edge where the shear layer begins. This paper will discuss the origins of this feedback phenomenon and the conditions under which it has the most impact. Selected examples of this phenomenon from the recent work conducted at Georgia Institute of Technology will be presented. Role of the boundary conditions and methods of controlling the phenomenon will also be discussed.

68 Click here to view scanned manuscript ICSV5 Paper Abstract Quantification of Inflow Turbulence for Prediction of Cascade Broadband Noise Authors: Donald B. Hanson, Pratt and Whitney, ( U.S.A.) Volume 2, page 515, paper no. 409 Abstract: The problem of broadband noise generated by turbulence from a rotor impinging on a downstream stator is examined from a theoretical viewpoint. Equations are derived giving sound power spectra in terms of the 3 dimensional turbulence wavenumber spectrum. Particular attention is given to issues of turbulence inhomogeneity related to separation of individual blade wakes in the near field of the rotor. It is shown that this inhomogeneity can be handled rigorously with no additional complexity in the noise equations. A procedure for measurement of turbulence at a stator inlet with a 2 probe data system is studied. In the process, formulas are derived to compute the 3D turbulence spectrum via transforms of measured cross-spectra and estimates are given for the required probe spacing.

69 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Radiation From a Tandem Two-Plate Array in a Fluid Flow: Dependence on Array Geometry and Flow Regime Authors: M.K. Bull, University of Adelaide, ( Australia) A.M. Blazewicz, University of Adelaide, ( Australia) J.M. Pickles, University of Adelaide, ( Australia) Volume 2, page 531, paper no. 425 Abstract: Acoustic radiation is generated by fluid flow over a tandem array of thick plates with bluff trailing edges, as a result of interaction between the leading edge of the downstream plate and vortices formed by flow separation from the upstream plate. The interaction gives rise to force fluctuations on the downstream plate, which constitute an acoustic dipole. The dominant component of the acoustic radiation is of discrete frequency, and the level is strongly dependent on the vortex flow regime which is established in the gap between the plates. The vortices may be stationary, trapped in the gap between the two plates, or may form a vortex street as a result of shedding from the upstream plate. Both flow regimes produce discrete frequency acoustic radiation, but with the onset of the vortex-street regime a dramatic increase in the level of acoustic radiation occurs. In broad terms, the flow regime - and hence the intensity of acoustic radiation produced - is determined by just two primary parameters: (i) the ratio S = s/c, of the lengths of any leading-edge separation bubble formed on the upstream plate to the chord-length c, of the plate, and (ii) the ratio G = g/t of the gap g between the plates to the plate thickness t. In general, the gap contains two trapped counter-rotating vortices or some form of vortex street, according as G > or < a critical value GC(typically - 3). For S <1, any leading-edge flow separation on the upstream plate is followed by reattachment on the same plate; flow separation from the trailing edge of the upstream plate then leads to a trapped-vortex or vortex-street regime in the gap (depending on the value of G). For S close to unity, the reattachment becomes intermittent and modifies both the trapped-vortex and vortex-street flow in the gap. ForS>1,leading-edge separation occurs without reattachment on the upstream plate, and the flow regime which is established depends also on the ratios s/(c1 + g) and s/(c1 + g + c2), where C2 is the chord-length of the downstream plate. Experimental data for a range of plate- array geometries will be presented to show that the various possible flow regimes are characterised by the coefficient of pressure on the upstream face of the downstream plate and by the Strouhal number of trapped-vortex oscillation or of vortex shedding from the upstream plate. The results clearly show that whenever the flow regime changes, these flow parameters and the level of the accompanying acoustic radiation all exhibit an abrupt change in magnitude.

70 Click here to view scanned manuscript ICSV5 Paper Abstract Aeroacoustic Characteristics of Perforated Wall and Cav- ity Authors: Kunisato Seto, Saga University, ( Japan) Kiichi Tokuhisa, Saga University, ( Japan) Muneharu Matsuoka, Saga University, ( Japan) Volume 2, page 539, paper no. 383 Abstract: A Perforation in a wall over which air flows may be considered to have both noise generating and noise absorbing effects. The authors have experimentally investigated the effects of perforated wall with and without shroud or cavity on noise reduction. First, aerodynamic characteristics has been improved by arranging the perforation according to cross area change of a De Laval nozzle. Next a perforated tube has been combined with a shroud in order that no leakage occurs through the perforation and also acoustic transmission loss increases. Third the length of the shroud has been extended longer than the main tube to give it an effect of a cavity. The cavity containing tube has some cut-off frequency and augments turbulence mixing which is good for combustion and reduces noise in some case. For those three cases, the authors investigated the effects of the porosity, the size of the perforation, the intersection angle between the axes of the perforation and the main flow and the perforation pattern. The directional angle of the perforation has been found to have influence on the performance of the perforated tube.

71 Click here to view scanned manuscript ICSV5 Paper Abstract Descriptions of Turbulence for Hydroacoustic Applica- tions Authors: Stewart Glegg, Florida Atlantic University, ( U.S.A.) William Devenport, Virginia Polytechnic and State University, ( U.S.A.) Volume 2, page 547, paper no. 381 Abstract: This paper describes the use of proper orthogonal decomposition for problems in hydroacoustics where structural response and sound radiation is caused by unsteady flow. For a complete solution, the flow in the region of interest must be calculated using numerical solutions to the Navier Stokes equations and this paper will describe how proper orthogonal modes may be used to specify the unsteady flow at the upstream boundary of the computational domain. This will be shown to offer significant savings in computational effort for both linear and non-linear problems providing the correct modes can be dert- ermined.

72 Click here to view scanned manuscript ICSV5 Paper Abstract Random Vibration Response of a Cantilever Beam to Acoustic Forcing by Supersonic Rocket Exhausts Dur- ing a Space Shuttle Launch Authors: Ravi N Margasahayam, John F. Kennedy Space Center, ( U.S.A.) Raoul E. Caimi, John F. Kennedy Space Center, ( U.S.A.) Volume 2, page 555, paper no. 282 Abstract: This paper presents a brief overview of recently completed research in the area of rocket noise and resulting dynamic behavior of launch pad structures. To gain accurate insight into the vibratory behavior of these structures, dynamic tests were integrated into the design process. Aspects of the acoustic load characterization procedure and the test-analysis correlation of random vibration structural response in the low frequency range (1 to 50 hertz) are presented.

73 Click here to view scanned manuscript ICSV5 Paper Abstract Nonstationary Transient Vibroacoustic Response of a Beam Structure Authors: Raoul E. Caimi, John F. Kennedy Space Center, ( U.S.A.) Ravi N Margasahayam, John F. Kennedy Space Center, ( U.S.A.) Jamal F. Nayfeh, University of Central Florida, ( U.S.A.) Volume 2, page 563, paper no. 281 Abstract: This study consists of an investigation into the nonstationary transient response of the Veriﬁcation Test Article (VETA) when subjected to random acoustic excitation. The goal is to assess excitation models that can be used in the design of structures and equipment when knowledge of the structure and the excitation is limited. The VETA is an instrumented cantilever beam that was exposed to acoustic loading during ﬁve Space Shuttle launches. The VETA analytical structural model response is estimated using the direct averaged power spectral density and the normalized pressure spectra methods. The estimated responses are compared to the measured response of the VETA. These comparisons are discussed with a focus on prediction conservatism and current design practice.

74 Click here to view scanned manuscript ICSV5 Paper Abstract Experimental Estimation of Aerodynamic Noise Radi- ated From Ventilating Gas Exit of Vehicle Tunnels Authors: Yoshiyuki Maruta, EBARA Research Co. Ltd., ( Japan) Sadao Mori, Metropolitan Expressway Public Corporation, ( Japan) Hiroo Tanabe, EBARA Corporation, ( Japan) Volume 2, page 571, paper no. 139 Abstract: It is necessary to estimate the exhaust-flow noise from ventilation tower when planning to increase the velocity of exhaust gas for preventing down-draft and down-wash around ventilation tower of vehicle tunnels. There are some aerodynamic noise source around the ventilating gas exit of vehicle tunnels, although many silencers are installed in ventilating duct for fully reducing the fan-noise. Small model experiments have been done by using the Quiet-Flow Acoustic Wind-Tunnel for studying the method of estimating aerodynamic noise radiated from ventilating gas exit of vehicle tunnels. In our experiments shape of exit port are rectangle and the length of exit-side were changed from 0.15m to 0.6m. The velocity of exhaust gas flow were changed from 10m/s to 30m/s.The aerodynamic noise power is proportional to the 6th power of gas-flow velocity and is proportional to the front side length of exit port. It is considered by these characteristics that the dominant noise source is aerodynamic noise generated by vortex shedding at the front side edge of exit port. Two-type equations with using side length of the exit for predicting exhaust flow noise have been induced by this experimental study. Basical methods to estimate the exhaust flow noise from ventilating gas exit of vehicle tunnels have been understood although there are still some subjects which need practical detail investigations.

75 Click here to view scanned manuscript ICSV5 Paper Abstract Analysis of the Acoustic and Hydrodynamic Fields Down- stream of a Sharp Edged Orifice in a Flow Duct System For Highly Turbulent Flows Authors: Rolf C. Pedersen, University of Western Australia, ( Australia) Michael P. Norton, University of Western Australia, ( Australia) Volume 2, page 579, paper no. 552 Abstract: Methods developed in the frequency domain are used for quantifying the hydrodynamic and acoustic components of the internal wall pressure fluctuations downstream of a flow disturbance in a flow duct system. This paper examines in detail, for frequencies below the (1,0) higher order acoustic mode, the acoustic and hydrodynamic fields for air flow downstream of a sharp edged orifice in a cylindrical flow duct. Particular attention is paid to the effect of the presence of a downstream standing wave field and the transmission of energy through the orifice.

76 Click here to view scanned manuscript ICSV5 Paper Abstract New Approach to the Theory of Aerodynamic Sound Authors: Alexander T. Fedorchenko, Moscow Phys. Tech. Institute, ( Russia) Volume 2, page 591, paper no. 521 Abstract: New nonlinear theory of sound generated by unsteady subsonic flow has been set up. This two-medium theory is based on the nonlocal invariant procedure of separating out the acoustic components in high-unsteady flow and so it departs radically from all conventional approaches, including well-known Lighthills model. The theory also gives means for the simulation of sound generation by specified unsteady mass and heat sources as well as by body forces. Thus the proposed theory does change some universally recognized opinions in aeroacoustics. Nonlocal mathematical model has been created for the . simulation of unsteady subsonic flows, viscous or inviscid as required, in a bounded spatial domain under rather complex boundary conditions. Continuously distributed sources of mass and entropy as well as intensive heat conduction can be taken into account. The exclusion of all acoustic effects is an important feature of this model which represents an essential extension of the classical model of incompressible fluid flow. In turn, this model forms a necessary basis for further application of the above aeroacoustic theory. A number of topical problems has been studied with the use of both theoretical and computational methods: nonlinear processes of instability in free mixing layers and in internal viscous flows; interactions between coherent vortex structures and small-scale turbulence; sound generation and acoustic feedback; self-excited acoustic resonances in ducts of various shapes (with cavities, steps, sudden expansions, bends), etc. Effective means of control over bounded subsonic flows have been developed. The creating of high-stable nonuniform flows with minimum sound emission represents the main research goal that could promote a lot of practical applications.

77 Click here to view scanned manuscript ICSV5 Paper Abstract Sonic Fatigue Study of an Aircraft Flap Like Structure Authors: L.C. Chow R.J. Cummins Volume 2, page 599, paper no. 439 Abstract: The consideration of acoustically induced fatigue failures in aircraft has been a design consideration for many years. Acoustic fatigue failures can be caused by the dynamic response of aircraft structures to unsteady pressure loading from aerodynamic and engine acoustic sources. The life structures is often difficult to assess accurately and maybe greatly affected by steady, thermal, in-plane and out-of- plane panel loads. The failures can results in maintenance and inspection burdens associated with the operation of the aircraft. In the late 60s to mid 70s, industry and research establishments were involved in the development of dynamic response methods and generation of endurance data culminating in the publication of ESDU data sheets and AFFDL design guide. The information is still extensively used today. However, the airframe manufacturer is required to meet evermore stringent performance and mass targets, being achieved through developments in optimised and efficient design of structures, and the introduction of new materials, There is a corresponding need for development in acoustic fatigue design methods and data. A three year research project is currently in progress using advanced analytical procedure finite element analysis and complementary experimental studies in order to develop dynamic response prediction procedures which will result in guides for the design of box-type structures, such as flaps, composed of conventional aluminium alloys, CFRP and GLARE materials. This paper reports upon the experimental phase of the project and the results.

78 Click here to view scanned manuscript ICSV5 Paper Abstract Effect of Non-Uniform Rotation on Acoustics and Aero- dynamics of Propellers Authors: S.R. Ahmed, DLR, Institute of Design Aerodynamics, ( Germany) J.P. Yin, Nanjing University of Aeronautics and Astronautics, ( China) W. Dobrzynski, DLR, Institute of Design Aerodynamics, ( Germany) Volume 2, page 607, paper no. 420 Abstract: This numerical study investigates the influence of non-uniform rotation on the aerodynamics and acoustics of multi-blade propellers. Non-uniform rotational motion is inherent to piston engine driven propellers. The effect of rotational speed non-uniformity is the generation of excess harmonic noise due to unsteady aerodynamic blade-loading. In case of a mismatch between the periodicity of non-uniformity and the basic blade passing frequency, additional harmonics are generated due to the complex blade kinematics. For a periodicity coincidence the effects are masked due to overlapping of the frequencies. The level of such extra harmonics may be high enough to dominate the overall A-weighted noise level. Propeller noise radiation for non-uniform rotation is no longer omnidirectional along azimuth and ex- hibits also a different characteristic in the polar direction.

79 Click here to view scanned manuscript ICSV5 Paper Abstract Computation Of Aircraft Noise Propagation Through The Atmospheric Boundary Layer Authors: Johan B.H.M. Schulten, National Aerospace Laboratory NLR, ( The Netherlands) Volume 2, page 615, paper no. 393 Abstract: Of all outdoor noise sources, aircraft probably have the largest impact on communities. As a result, the accurate prediction of aircraft noise exposure is of great interest. Nevertheless, conventional procedures for quantifying aircraft noise draw heavily on empirical data in which source and propagation effects are more or less statistically lumped together. A physically more relevant modeling of aircraft noise propagation is the ray acoustics approximation. Whereas ray acoustics techniques are well developed for stationary sources, they are not often applied to aircraft noise because the aircraft motion in principle requires many time-consuming computations to obtain the time history of a single takeoff or landing event. The present paper describes the application of the method of ray-tracing to a source moving along a three-dimensional path in a realistic atmosphere. The method is illustrated by typical examples of the effects of a non-uniform wind and temperature profile such as the formation of acoustic shadow zones without any noise and, alternatively, zones with multiple reflections. It is shown that large reductions in computation time can be obtained if the flight path is close to level, which is factual for the majority of civil aircraft movements.

80 Click here to view scanned manuscript ICSV5 Paper Abstract Role of Enhanced Mixing on the Far-Field Noise of Su- personic Jets Authors: Anjaneyulu Krothapalli Volume 2, page 625, paper no. 346 Abstract: The paper examines the question: Does a mixing enhancement necessarily result in far-field noise reduction in supersonic jets? Several experiments were conducted to come up with an answer to the above question, The first experiment deals with examination of noise generated by a Mach 2 ideally expanded supersonic with counterflow. The counterflow technique depends on the creation of a counterflowing stream of air around the periphery of the primary jet column in the neighborhood of the nozzle exit. The creation of the secondary flow gives rise to a reduction in the jet exit plane pressure, which requires that the total pressure supplied to the jet be correspondingly reduced to maintain a nominally ideally expanded jet flow field. Experiments were conducted at a primary stream Mach number of 2 for jet stagnation temperatures between 286 K (cold jet) and 715 K (hot jet). The mixing characteristics of the jet were examined by conducting mean and fluctuating total pressure measurements in the axial and radial planes of the jet downstream of the nozzle-collar assembly. Fluctuating pressures measured along the geometrical axis of the jet indicate that the peak turbulence level lies closer to the jet exit when counterflow is applied. Complementary measurements made in the shear layer under similar flow conditions, indicate a significant increase in the overall turbulence level in the jet shear layers due to counterflow. These observations were essentially independent of the jet stagnation temperature. The corresponding mean total pressure measurements indicate that annular counterflow reduces the potential core length of the supersonic jets by a factor of two. Exhaustive studies conducted in our laboratory and summarized in Strykowski, Krothapalli & Jendoubi [1] attribule this mixing enhancement to increased shear layer growth rates by more than 60% compared to incompressible shear layers at similar velocity and density ratios. These aerodynamic measurements indicate that the counterflow significantly reduces the potential core, and therefore the supersonic region of the jet, and hence would appear to be an attractive control scheme for supersonic noise reduction. The most surprising result of the study was that the angle between the jet axis and the peak in the Overall Sound Pressure Level (OASPL) remained fixed when counterflow was supplied, despite the rather dramatic upstream shift in the peak turbulence level in the jet. This cast doubt on the notion that the primary source of the low frequency Mach wave radiation lies near the location of the peak rms pitot pressure. However, a closer examination of the measurements as outlined in King, Krothapalli & Strykowski [2] revealed that the reduction in the convection velocity of disturbances in the jet shear layer with counterflow essentially balanced the upstream shift in source location. Noise spectra obtained as a function of circular arc angle were used to explain why the OASPL of the counterflowing jet was higher at some angles relative to the free jet, but lower at others. In general, counterflow increases the noise levels at higher frequencies, suggesting that counterflow excites the smaller scale turbulence, a notion that is consistent with earlier findings that the rms pressure level in the jet shear layer was increased due to counterflow. At larger angles, the counterflow caused a reduction in the sound pressure level at all frequencies. Thus, the counterflow seems to interfere with the Mach wave radiation mechanism. In summary, these measurements suggest that enhanced mixing in the region close to the nozzle exit may not necessarily result in far-field noise reduction of a supersonic jet. This is primarily due to increased turbulence production that is closely associated with the enhanced mixing processes. The potential for using devices such as tabs and modifications to the nozzle exit geometry which may allow superior mixing through the introduction of streamwise vorticity without . significant thrust loss is explored. Although the mean and turbulent flow field of a jet at the nozzle exit with significant streamwise vorticity is very different than a corresponding axisymmetric jet , it does not appear to have a significant effect on the far field mixing noise of a supersonic jet. The flow and noise fields of a diamond-shaped jet are used to substantiate the above observation.

81 82 Click here to view scanned manuscript ICSV5 Paper Abstract The Low Frequency Acoustic Loading Vibration Response Analysis of Structures Authors: Keiko Yoshida, Mitsubishi Electric Corporation, ( Japan) Volume 2, page 627, paper no. 317 Abstract: The purpose of this study is to solve the vibration responses of spacecraft equipment structures, especially light weight rigid panels, such as a solar array paddle or an antenna, excited by an low frequency acoustical noise field. In this paper, first, the direct loading pressure to the structure in a random sound field, is derived and the response calculation method using FEM is proposed. Second, the derivation of the direct loading pressure to the structure is experimentally verified, using a honeycomb panel of which the edge was bolted to a stand, in the steady-state sound pressure field. Finally, experimental results of the acceleration responses of the panel in the random sound field are found to agree with the simulation results of this proposed calculation method. And the simulation results of the usual frequency response method contain a high degree of error compared with the results of the new method. This method is applied to a practical antenna panel, and the results of the simulation agree with the acoustic test.

83 Click here to view scanned manuscript ICSV5 Paper Abstract Dynamic Behaviour of the Airplane Horizontal Tail: Se- lection of the Model for Correct Simulation Authors: N.I Baranov, Russian Aviation Co. Lt, ( Russia) S.N. Baranov, Russian Aviation Co. Lt, ( Russia) Lev S. Kuravsky, Russian Aviation Co. Lt, ( Russia) K.P Zhukov, Russian Aviation Co. Lt, ( Russia) Volume 2, page 635, paper no. 287 Abstract: Computer experiments were undertaken to study dynamic behavior of a horizontal tail during the flight in turbulent atmosphere. This work was carried out to select acceptable variant of fixation and clearance between the stabilizer and elevator to avoid strikes.The method of correction by elastic and inertial connection insertion in Galerkin formulation was used to obtain a set of ordinary differential equations representing the structure motion. Under consideration is a sequence of mathematical models making each other more accurate. The following factors were successively taken into account: bending of the stabilizer and elevator, geometrical non-linearity of the structure response, effeot of the motion of a whole airplane, and torsion of the elevator. This approach made it possible to assess how important and correct each of these model modification for the estimations in question.To check the simulation correctness, computed results were compared with available experimental data obtained by ground vibration and flight testing. The estimations in question allowed aerospace designers to select optimal modifications of the horizontal tail.

84 Click here to view scanned manuscript ICSV5 Paper Abstract Prediction of Aerodynamic Noise From Multi-Hole Multi- Stage Expansion in Control Valve Authors: C.J. Gangadhara Gowda, Indian Institute of Technology, ( India) Y.G. Srinivasa, Indian Institute of Technology, ( India) Pramod S. Mehta, Indian Institute of Technology, ( India) Volume 2, page 643, paper no. 280 Abstract: Control valves are the flow elements used in chemical process industries and steam power plants for reg- ulating fluid flow in pipe lines. Control valve regulate the flow and convert pressure energy into kinetic energy. A portion of this energy is converted into acoustic energy which is responsible for generating noise. Studies on aerodynamic noise generated by control valves have attracted attention of several researchers for control of noise produced by them which is considerably high compared to the OSHA standards. The aerodynamic noise generated in control valve depends upon the pressure ratio between the upstream and downstream of the valve. For a higher pressure ratio in the system, the broad band shock noise is generated if the expansion is carried out in a single stage. This noise level is far greater than the noise level generated at sub-critical pressure ratio. The noise reduction in control valve, therefore can be achieved by allowing the fluid to expand in different stages such that the pressure ratio in each stage is kept below critical pressure ratio. The internal peak frequency of the noise generated by the control valve depends upon the jet diameter. Multi-hole expansion arrangement shifts the internal peak frequency depending upon jet diameter. This shift may be achieved such that the peak frequency occurs beyond the audible range hence reduce the noise level. The ability of the multi-hole and multi-stage arrangements to reduce noise can be combined for use in control valve trim design. From these considerations, the present study is an attempt to predict the aerodynamic noise generation from multi-hole multi-stage arrangement. In the present work the noise generated by a (i) multi-stage and (ii) multi-hole multi-stage expansion in a control valve are predicted for various pressure ratios. The results are compared with the predicted value of noise generated by a conventional control valve. There is considerable reduction in noise level when a multi-hole multi-stage configuration is used.

85 Click here to view scanned manuscript ICSV5 Paper Abstract The Effect of Nozzle Geometry on the Noise of High- Speed Jets Authors: Christopher K. W. Tam, Florida State University, ( U.S.A.) Volume 2, page 651, paper no. 220 Abstract: Reducing high-speed jet noise is currently a high priority research and development item of the aircraft industry, The objective of this paper is to examine the effectiveness of jet noise reduction by nozzle geometry modification, The use of nozzles with complicated geometry would, inevitably, lead to thrust loss, Our consideration is, therefore, confined to practical geometries for which the thrust loss is reasonably small, In order to focus attention on nozzle geometry alone, we will only consider jets with a single stream. Multi-stream jets, invariably, would introduce thermodynamic and other flow parameters as variables for noise suppression, We have carried out a detailed analysis of the noise data from 6 nozzles operating at supersonic conditions, The nozzle geometry includes a CD configuration, a conical nozzle, a CD plug nozzle, a conical plug nozzle and two 20 chute annular plug suppressor nozzles, The results indicate that if the jet fluids mix quickly, that is, they combine into a single jet at a short distance downstream of the nozzle exit, the noise intensity and spectral characteristics are nearly the same as those of a simple round jet. There is a strong implication that external mixing introduced by nozzle geometry modification is not an effectiveness way to reduce jet noise.

86 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract An Influence of SST-2 Mixer-Ejector Nozzle Elements Variations on its Aerodynamic and Acoustic Character- istics Authors: Sergey Ju. Krasheninnikov, Central Institute of Aviation Motors, ( Russia) Alexei Mironov, Central Institute of Aviation Motors, ( Russia) Eugeni V. Pavlyukov, Central Aerohydrodynamic Institute TsAGI, ( Russia) Vladimir Jitenev, Central Aerohydrodynamic Institute TsAGI, ( Russia) Andrey V. Shenkin, Central Aerohydrodynamic Institute TsAGI, ( Russia) Volume 2, page 659, paper no. 187 Abstract: In earlier work of CIAM/TsAGI/SNECMA the acoustic and aerodynamic characteristics of 2-D mixer- ejector models, which could be prototype of real variable nozzle for future supersonic aircraft, were experimentally investigated. It was shown that 2-D mixer-ejector can give about 10 EPNdB noise reduction in take-off and flight over check points. Its efficiency is not worse than for conventional noise suppressors - about 34.5PNdB per 1% thrust loss at static conditions. In the present work the possibility of the increasing of the efficiency of the previously designed mixer-ejector by means of variation of its elements was studied. The results of the investigation of the influence of auxiliary slots and acoustic lining at ejector walls on mixer-ejector acoustic and thrust performances are presented. The flow structure and its influence on mixer-ejector acoustic characteristics was also studied.

87 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract CFD- Analysis of Fan Aeroacoustics- Comparative Stud- ies Authors: Dieter Lohmann, DLR Inst. of Design Aerodynamics, ( Germany) H. Capdevila, Siemens Electric Ltd, ( Germany) U. Stark, Technical University of Braunschweig, ( Germany) M. Kuntz, DLR Inst. of Design Aerodynamics, ( Germany) Volume 2, page 669, paper no. 132 Abstract: The need of aeroacoustically highefficient fans requires more detailed investigations of three dimensional effects and separated flow analysis. Comprehensive studies and code validation for fans have shown, that further development - especially for the influence of sweep - is necessary. Therefore, two different Navier-Stokes Codes, a lifting surface code and a classical method for 3-D cascade flow were used to compute a ducted swept radiator fan. The results of the method are checked against each other and compared with experiments to firstly validate the codes in aerodynamis and secondly deliver data for acoustic calculations. Here the aerodynamic pressure and boundary displacement thickness are taken for the acoustic field computations at the fan face using the acoustic analogy method. The far-field is computed by the use of Rayleigh’s formula. Different flow rates were modeled for a 7-bladed fan geometry. The computational results of static pressure and efficiency are compared with experimental data. Indicated flow separation of both, a forward and an aft swept fan have been analysed. The effect of turbulence modeling and different grid size has been investigated. The linear methods used for the aeroacoustic fan design are validated for local data. In order to check the prediction capability of the DLR acoustic methods, acoustic spectra of periodic and stochastic noise parts have been calculated at different angles around the fan face and compared with measured data.

88 Click here to view scanned manuscript ICSV5 Paper Abstract Numerical Simulation on Screech Tone Generated by Two-Dimensional Supersonic Jets Authors: Tetsu Yamagishi, University of Tokyo, ( Japan) Shojiro Kaji, University of Tokyo, ( Japan) Volume 2, page 691, paper no. 100 Abstract: The screech tone generated by a two-dimensional supersonic jet is studied numerically by solving the Euler equations with the ENO (essentially non-oscillatory) scheme. The details of shock cell structure, large-scale vortices, and sound generation mechanisms are elucidated. Numerical results for streak lines show clearly that shear layers begin to roll up at the third shock cell and grow into large-scale vortices destroying the shock cell structure further downstream. Beyond the third shock cell large-scale vortices cease to grow and convect at a nearly constant speed. In the growing process of large-scale vortices, it is observed that the jet plume and the vortex core compress the ambient air confined between them increasing its total temperature, whereas both of them losing their own energy. This higher energy fluid is pressed out of the vortex structure forming a sound source. Acoustic intensity analysis indicates that several sound sources along the jet plume bring acoustic interactions which make it possible that an acoustic energy feedback occurs only at the first shock cell.

89 Click here to view scanned manuscript ICSV5 Paper Abstract Simulation of Aerodynamic Sound Generation on Air- foils in Low Mach-number Flows Authors: G. Guidati, University of Stuttgart, ( Germany) Siegfried Wagner, University of Stuttgart, ( Germany) Volume 2, page 699, paper no. 90 Abstract: The sound generation due to convected turbulence (vorticity) interacting with the leading edge of an arbitrary airfoil was treated by GUIDATI, ET AL [1]. In this approach the spectral decomposition of a point vortex being passively convected by the mean flow results in vorticity waves which are taken as basic source patterns. The acoustic analogy by HOWE [2] is used and the diffraction problem is solved by employing boundary-element methods. Comparison with recent experiments shows that the difference due to airfoil shape is predicted within an accuracy of 1-2 dB. In the present paper this approach will be extended. So far, only one vorticity wave on both sides is taken. Since a turbulent flow-field is completely filled with vorticity, a larger number will be employed. This allows to prescribe skewed gusts, ie turbulent length scales in flow and cross-flow direction. A second extension concerns the interaction of inflow turbulence with the trailing edge. In the AMIET model [3] a steady KUTTA condition is applied at the trailing edge and the development of a turbulent boundary layer is neglected. In reality, the question of a correct KUTTA condition is unsolved. Furthermore, the boundary layer will radiate additional sound and modify the inviscid flow field. Simulations with and without steady KUTTA condition will be presented. The deflection of streamlines due to a boundary layer will be considered. This will allow to estimate which part of the airfoil - leading or trailing edge - radiates more sound in case of turbulent inflow. Comparison with experiments will be shown.

90 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Effects on Flow Separation Authors: Fritz-Reinhard Grosche, German Aerospace Research Establishment (DLR), ( Germany) Volume 2, page 707, paper no. 69 Abstract: Flow visualization techniques were used to study the influence of sound waves on flow separation from a wing of low aspect ratio 3:1. Two different technique of acoustic excitation have been applied: 1. Spherical sound waves from a loudspeaker within the acoustic far field (Global excitation) 2. Sound waves focused by an elliptical mirror on a small region of the wing (Localised excitation). The experimental results demonstrate that acoustic excitation in a suitable frequency range can reduce the flow separation, which occurs at high angles of incidence all along the leading edge, to a much smaller turbulent separation region that mainly affects the central part of the wing. The tests with acoustic waves focused on a small part of the wing give insight into the dependence of the spanwise structure of the separation on, the position of the excitation region. We made video-recordings of the flow visualization studies which illustrate the characteristic flow features obtained with global and localised acoustic control of the leading edge separation. Also presented are experiments on the control of separation by internal acoustic forcing through a slot in the surface of the model.

91 Click here to view scanned manuscript ICSV5 Paper Abstract Dynamic Behaviour of a Rectangular Unbaffled Plate In- mersed in a Diffuse Field Authors: F. de la Iglesia, Universidad Polictecnica de Madrid, ( Spain) P. Garcia-Fogeda, Universidad Polictecnica de Madrid, ( Spain) Volume 2, page 715, paper no. 57 Abstract: A method to estimate the response of an aerospace structure excited by the acoustical loads produced during a rocket launch is presented. These elevated pressure loads can be critical in the design of large lightweight structures such as solar arrays and communication reflectors where high acceleration levels can be achieved. The resulting acoustic field can be considered as a diffuse field composed of a large number of uncorrelated incident plane-waves traveling in different directions that impinge over the structure surface. A Boundary Element Method has been used to compute the pressure jump produced by an incoming plane-wave in an unbaffled rectangular plate and the fluid-structure coupling loads generated by the plate own vibrations. This method is based on Kirchhoffs integral formulation of the Helmholtz equation for the pressure field taking into account the Sommerfeld radiation condition. The generalized forces matrix due to the fluid loading is then determined utilizing the vacuum modes of the plate as base functions of the structural displacement in the present problem. These modes are obtained by means of a Finite Element Model. An iteration procedure has been developed to calculate the natural frequencies of the coupled fluid-plate system. Comparisons of the present method with various experimental data and other theories show the efficiency and accuracy of this method for any support condition of the plate and the validity of the present procedure for the values of the frequency of excitation that appears in an acoustical test performed in a large reverberant chamber.

92 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustical Planning of a Building Containing Both Apart- ments and a Theatre Authors: Leif Akerlof, Ingemansson Technology AB, ( Sweden) Volume 2, page 729, paper no. 444 Abstract: In Stockholm an old electric power station built in the 1920s is being converted into a combined theatre and apartment building. The four storey theatre contains 400 seats and it is flanked with apartments inside the power station on one side and in a new building connected to the old one on the other side. The foyer of the theatre and a restaurant are situated on the ground floor directly below some of the apartments. This poses a number of problems. Before and during the design of the building an extensive acoustical investigation was made in order to fulfil the tough acoustical demands. It is hard to avoid disturbances from neighbours in a common apartment building and in this case the sound levels of the disturbances are quite different. The activities in the theatre must not cause disturbances in the apartments even though there are performances late at night. Some of the considerations that had to be taken are presented and also some solutions that were used.

93 Click here to view scanned manuscript ICSV5 Paper Abstract Room Acoustics Characterization Following a Phonon Transition Approach Authors: Luis Bento Coelho, CAPS-Instituto Superior Tecnico, ( Portugal) D. Alarcao, CAPS-Instituto Superior Tecnico, ( Portugal) Volume 2, page 735, paper no. 405 Abstract: A technique is presented for the characterization of sound fields in enclosures by considering the three dimension random walks of phonons inside the room, Different wall materials as well as arbitrary geometrical arrangements can be dealt with. The different transition probabilities are calculated considering the solid angles of all walls. At every transition, the phonon density over every wall is changed. The sound intensity at a referrence point is then evaluated by considering diffuse wall radiation. The room impulse response, reverberation time and inteligibility indexes can be calculated by assuming that every transition takes place at a rate given by the mean relaxation time. The model was seen to yield results in good agreement with simple theories for a quasi-diffuse sound field in en enclosure with a homogeneous wall arrangement. For cases other than this, the simulation results show that the sound intensity increases near to a highly reflecting surface. The reverberation time and the inteligibility indexes depend on the reference point location for a non-diffuse field. Computation of the model is fairly fast. Compar- isons between theory and experiment for different shapes of auditoria showed good agreement.

94 Click here to view scanned manuscript ICSV5 Paper Abstract The Variance of Pure Tone Reverberant Sound Power Measurements Authors: John L. Davy, CSIRO DBCE, ( Australia) Volume 2, page 741, paper no. 548 Abstract: The 1996 version of the draft international standard ISO/DIS 3741, "Acoustics - Determination of sound power levels of noise sources using sound pressure - Precision methods for reverberation rooms" deleted the room qualification procedure for the measurement of discrete frequency components. The alternative multiple source position method has been retained. This paper shows that there is an error in the constant in the equation for determining the number of source positions in the retained alternative method. It also shows that the multiple source position method is not sufficient at low modal overlap. Thus the room qualification procedure should be reinstated. The measurement variance can be split into source position, receiver position and room variance. The room variance depends on the distribution of modal spacings. Earlier theoretical and numerical calculations used the Poisson or "nearest neighbour" distributions. Both these distributions produce non-zero room variance. The Gaussian Orthogonal En- semble (GOE) distribution, which is currently believed to be correct, produces zero room variance at high modal overlap. At low modal overlap, the GOE and "nearest neighbour" distributions produce room variance values which tend towards the non-zero values produced by the Poisson distribution.

95 Click here to view scanned manuscript ICSV5 Paper Abstract The Relevance of the Biot Theory for Prediction of Sound Transmission Through Partitions Incorporating Porous Layers Authors: Elizabeth A. Lindqvist, Royal Melbourne Institute of Technology, ( Australia) Volume 2, page 749, paper no. 361 Abstract: A car floor is normally comprised of a decorated soft trim on a heavy layer with a net weight of4-8 kg/m2 and2-4mmthickness, which is backed by a porous or fibrous material. This is either simply fitted to the steel floor pan or glued to it. Such a system essentially constitutes a double leaf partition with a high damping filler. In order to facilitate design of carpeting systems to provide optimal sound insulation properties, a good model of sound transmission through such a structure is required. Several models of sound propagation through porous materials are available. These models have been compared and in particular the Biot model has been studied. This model predicts that three distinct waves will propagate through a porous material. Under what circumstances must each of these waves be included in the model and when can we neglect one or more of them? Do porous plastics behave in a similar way to fibrous materials? As is often the case, evaluation of a theoretical model is hampered by lack of experimental values of parameters. We have therefore sought to relate measurable quantities to the theoretical parameters.

96 Click here to view scanned manuscript ICSV5 Paper Abstract Objective and Subjective Acoustical Parameters in Catholic Churches Authors: Antonio P.O. Carvalho, University of Porto, ( Portugal) Antonio E.J. Morgado, University of Porto, ( Portugal) Volume 2, page 757, paper no. 319 Abstract: This study reports on objective and subjective acoustical field measurements made in a major survey of 36 Catholic churches in Portugal built in the last 14 centuries. Monaural acoustical measurements (RT, EDT, C80, D50, TS and L) were taken at several source/receiver locations in each church and a group of college students was asked to judge the subjective quality of music. The listeners in each church evaluated live music performances at similar locations in each room. Evaluation sheets were used to grade the listeners’ Overall Impressions of room acoustics qualities and also Loudness, Reverberance, Intimacy, Envelopment, Directionality, Balance, Clarity, Echoes, and Background Noise. This paper concentrates on the relationships of the subjective parameters with the objective room acoustics measures and with the architectural features of the churches. The results are graphed and analyzed by comparisons. Cor- relation analyses and statistical modeling identified significant relationships among the measures. For instance, linear correlation coefficients (|R|) of 0.8-0.9 were found for the relationships: Reverberance/RT and Clarity/C80; the maximum |R| found was 0.93 for Echoes. Regarding architectural features the maximum |R| found was 0.87 between Intimacy and Tonal Volume.

97 Click here to view scanned manuscript ICSV5 Paper Abstract Computer Prediction of Sound Propagation in Enclosed Spaces Using a Pressure Based Model Authors: S.M. Dance B.M. Shield Volume 2, page 765, paper no. 273 Abstract: Previous researchers have all found abnormal sound fields in empty enclosed spaces. The sound ap- peared to propagate in such a way as to increase in level with increasing distance from the sound source, although it returned to its expected level at the farthest distances. These anomalies were caused by interference, which was dependent on phase shifts.A computer model, PHASE, was previously used to predict interference effects at two frequencies in two spaces. The model has been optimised, extended and modified to predict across the full frequency range efficiently. To validate the model sound levels in a reverberation chamber, as measured by Hodgson, were predicted at both a low and a high frequency. In addition the overall sound levels were predicted in an empty factory space to illustrate the accuracy of the model for practical purposes. To this end the predictions of an intensity based model, CISM, were used as a comparison.

98 Click here to view scanned manuscript ICSV5 Paper Abstract Restaurants And Cinemas Downstairs: A Pleasure Or A Failure? Authors: M. Asselineau, Peutz & Associates Acoustical Consultants, ( France) Volume 2, page 773, paper no. 259 Abstract: One of the urban environment challenges is to manage to locate such leisure places as cinemas, restaurants, or even discotheques, as close as possible to the living quarters. While this can be reasonably achieved in brand new buildings, with careful acoustical and urban planning and engineering, it often. proves tricky, or even impossible, to practice in the kind of older buildings that usually are to be found at the core of European cities.This paper aims to submit and discuss a few case studies, ranging from real success to total failure, looking into the context of the situation as well as into the technical solutions and legal strategies that were applied.One of the main conclusions is that whenever any beneﬁt is proved to result from the presence of such leisure places close to home, the neighborhood can much more readily accept the acoustical implications. However, when no thought is given to the acoustical problems, the technical solutions - and the relational eﬀorts -needed to correct the situation, often prove to be beyond the capabilities of the operators.

99 Click here to view scanned manuscript ICSV5 Paper Abstract Plasterboard on Masonry: The Effects of Direct Fixing Authors: Mark Debevc, Boral Plasterboard, ( Australia) Volume 2, page 781, paper no. 35 Abstract: The method of directly attaching plasterboard by adhesive daubs to both sides of a masonry wall will result in increased sound transmission which can occur at low, mid, or high frequencies. The proximity and the magnitude of reduction in transmission loss over the frequency bands is dependent on combinations of the number of fixing points and the depth of the cavity behind the plasterboard. The effect on the determined Sound Transmission Class (STC) ranged froma1to8dBdecrease over that of the bare wall. Measurements were conducted on a 110 mm hollow block wall with the plasterboard bonded by various configurations in the adhesive daub centres and thickness. This paper will discuss contrasts in measurement results of airborne sound insulation which show that relatively small structural changes can make large differences to the transmission losses, and hence the STC, when plasterboard is directly fixed to both sides of a block wall.

100 Click here to view scanned manuscript ICSV5 Paper Abstract A Convenient Accuracy Criterion for Time Domain FE- Calculations Authors: Morten Skaarup Jensen, Odegaard & Danneskiold-Samsoe, ( Denmark) Volume 2, page 793, paper no. 533 Abstract: The key strength of the finite element (FE) method in acoustics is it’s ability to predict the solutions to a very wide range of problems with high accuracy. Unfortunately, increased accuracy usually implies increased computation costs, so means for evaluating accuracy of such calculations are therefore essential for practical use of the method. This paper presents an accuracy criterion that is well suited for time domain calculations - using traditional convergence theory and some tabulated values, one can easily obtain an a’priori estimate of the element and time step sizes that will be required to fulfil this criterion. The criterion has the advantage of being based on the dispersion error, which is the main error in time domain FE-calculations. In addition, it has the advantage of being flexible regarding element type and will presumably also be able to incorporate singularies. By contrast, the commercial standard - the six elements per wavelength rule of thumb - is not as theoretically well founded and works only for linear elements when singularities can be neglected. The two methods are compared in an example that doesn’t contain singularities.

101 Click here to view scanned manuscript ICSV5 Paper Abstract Comparative Study of Boundary Element and Finite Ele- ment Formulations for Evaluating Sound Radiation from Plates Authors: Jean-Pierre Coyette, LMS Numerical Technologies, ( Belgium) Luc Cremers, LMS Numerical Technologies, ( Belgium) Volume 2, page 801, paper no. 302 Abstract: Sound radiation from plate structures usually relies on either direct or indirect boundary element (BE) formulations. BE formulations offer some specific advantages (exact treatment of the Sommerfeld radiation condition, boundary surface mesh). On the other side, finite element (FE) formulations can be extended in such a way that exterior acoustic problems can be treated and offer attractive features (reduced CPU times, uniqueness of the solution). A refined infinite element formulation has been used for this purpose. This formulation enables the use of variable order interpolation functions and the selection of different coordinate systems (spherical and oblate spheroidal coordinates in the present case). A practical comparison of these two approaches is presented for sound radiation from an elastic plate mechanically excited. Both field values and integrated quantities (like the radiated power) are involved in this comparison.

102 Click here to view scanned manuscript ICSV5 Paper Abstract A Discussion on Finite Elemental Analysis of Sound Field in Rooms With Sound Absorbing Materials Authors: Toru Otsuru, Oita University, ( Japan) Tomoyuki Uchida, Oita University, ( Japan) Volume 2, page 809, paper no. 182 Abstract: In the analysis of architectural acoustics, the transient response in the three dimensional room with absorbent walls is essentially important. Then, several approaches are presented here to treat the dissipation and to obtain the transient response efficiently. Although the finite element method requires more memory in a computer compared to that of the boundary element method, the finite element method has stronger points in some cases. However, some physical assumptions and some mathematical considerations help to reduce the required memory, which makes a way to such an analysis as is on an auditorium. So, the choice of the combination of them is essential, especially in the analysis on a huge system. To make the point clearer, several computations are carried out. With the results, the characteristics of them are discussed.

103 Click here to view scanned manuscript ICSV5 Paper Abstract Optimisation of a Concrete Block for a Diesel - Aggre- gate Authors: Kari Saine, Wartsila NSD Corporation, ( Finland) Olli Nuutila, Tampere University of Technology, ( Finland) Hannu Tienhaara, Wartsila NSD Corporation, ( Finland) Volume 2, page 817, paper no. 165 Abstract: A way to use finite element method (FEM) to create an FE-model of an entire aggregate, total mass 100- 700 ton, is presented in this paper. The aggregate consists of a medium speed diesel engine and an alternator, which have been mounted to a concrete block. The whole system can be mounted flexibly or rigidly to the ground.Usually international standards do not take into account elastic natural frequencies of the concrete block when defining the dimensions. That is why these structures are in many cases over dimensioned. The rapid development of the digital computers have however brought new possibilities to calculate big and complex structures beforehand. In this context the exact dimension is very important because a combustion engine has many excitation frequencies and most of them are not allowed to be near a natural frequency.The methodology of realistic modelling of a big aggregate using finite element method is described in this paper. The natural frequencies of the structure can be calculated with the achieved model. Also the static and dynamic stresses and responses for given excitations are computed. On the basis of the results the concrete block can be optimized by which noticeable cost savings can be achieved.The results of calculations and the realistic FE-model were verified by measurements on complete aggregate in the field. The measurements were carried out by using servo-hydraulic shaker, by which the natural frequencies and mode shapes of the concrete block could be found. Also the operational deflection shapes and responses were measured. The calculated values correspond to the measured ones very well.

104 Click here to view scanned manuscript ICSV5 Paper Abstract An Introductory Study of the Convergence of the Direct Boundary Element Method Authors: Peter M. Juhl, Technical University of Denmark, ( Denmark) Volume 2, page 825, paper no. 98 Abstract: Although boundary element methods have been used for three decades for the numerical solution of acoustic problems, the issue of convergence is not well known among acoustic engineers. In this paper the concept of convergence is introduced in an intuitive and empirical style. The convergence of an axisymmetric boundary element formulation is studied using linear, quadratic or superparametric elements. It is demonstrated that the rate of convergence of these formulations is reduced for calculations involving bodies with edges (geometric singularities). Two methods for improving the rate of convergence for these cases are suggested and examined.

105 Click here to view scanned manuscript ICSV5 Paper Abstract Effects of Drilling Degrees of Freedom in the Finite El- ement Modeling of Infinite Domains Authors: Jaehwan Kim, Inha University, ( Korea) Volume 2, page 833, paper no. 474 Abstract: This paper deals with a hybrid finite element modeling of wave scattering problems in infinite domains. Scattering of waves involving complex geometries in conjunction with infinite domains is modeled by introducing a mathematical boundary. On the mathematical boundary, the finite element representation is matched with analytical solution in the infinite domain in terms of fields and their derivatives. Drilling degrees of freedom at each nodes of the finite element model are introduced to take into account the transverse component of the elastodynamic field more precisely. To verify the roles of drilling degrees freedom and the slope constraint, normal incidences of P and SV waves are considered. For the P-wave incidence, the use of slope constraint suppresses artificial reflection at the mathematical boundary and for the SV-wave case, the use of drilling degrees freedom reduces numerical error at irregular frequencies.

106 Click here to view scanned manuscript ICSV5 Paper Abstract Performance Evaluation of Finite Difference and Finite Element Methods in the Real-Time Simulation of Flexi- ble Robot Manipulators Authors: Osman Tokhi Z. Mohamed, University of Technology Malaysia, ( Malaysia) A.K.M. Azad Volume 2, page 841, paper no. 358 Abstract: This paper presents an investigation into the performance evaluation of finite difference and finite element methods in the real-time simulation of flexible robot manipulator systems. A constrained planar single-link flexible manipulator is considered. Finite-dimensional simulation environments characterising the dynamic behaviour of the manipulator are developed using finite difference and finite element methods. The simulation algorithms thus developed are implemented on general-purpose digital processors. Experimental results verifying the performance of the algorithms in characterising dynamic behaviour of the system and comparative performance evaluation of the algorithms on the basis of accuracy and computational efficiency are presented and discussed.

107 Click here to view scanned manuscript ICSV5 Paper Abstract Low Cycle Carrying Capacity of Bearings With Hard- ened Rolling Layer Authors: Ivan Prebil, University of Ljubljana, ( Slovenia) Robert Kunc, University of Ljubljana, ( Slovenia) Matjaz Torkar, Institute of Metals and Technology, ( Slovenia) Volume 2, page 849, paper no. 335 Abstract: The paper deals with the problem of the actual carrying capacity of a rolling contact in large axial bearings with surface hardened raceway. The carrying capacity of such bearings is usually given with the maximal permissible force on the rolling element with the highest load. The established criteria of maximal permissible plastic deformation of the raceway, and the maximal allowed subsurface stress on the hardened layer boundary give widely varying values for the carrying capacity of the rolling contact. In order to determine the actual carrying capacity of the rolling contact in axial bearings with low speed of rotation, considering base material properties, hardness and thickness of the hardened layer, and the geometry of the contact, we have measured the models of bearing raceways made of 42CrMo4 and C45 materials. The loads were static and low cycle dynamic. We have determined the cyclic curves (force - deformation), limit of fast increase in (elastic and plastic) deformation gradient, and the size of the contact surface. Simultaneously with the experiment, we have checked the sub surface stresses using a FEM model, considering the material nonlinearities. On the basis of the measurement results and the FEM model we would like to set up a simpliﬁed mathematical relation that gives the permissible contact force considering the base and hardened material properties, and the geometric model of the rolling contact.

108 Click here to view scanned manuscript ICSV5 Paper Abstract FEM Complex Envelope Displacement (CED) Analysis for Damped High Frequency Vibrations Authors: G. Verbeek, Eindhoven University of Technology, ( The Netherlands) N.C.P.J. Geerts, Eindhoven University of Technology, ( The Netherlands) Jan W. Verheij, TNO Institute for Applied Physics TU-Delft, ( The Netherlands) Volume 2, page 857, paper no. 305 Abstract: The analysis of linear dynamic (acoustic) systems with deterministic loading, boundary conditions, and material parameters can nowadays be performed by routine FEM/BEM calculations. Even for very large systems this approach is feasible by application of commonly used CMS reduction techniques. However the FEM analysis still is limited for a specific problem to a frequency band with a sufficiently low upper excitation frequency. This low frequency restriction is present because of the maximal number of degrees of freedom, despite of the ever increasing computer power. Complex envelope displacement analysis (CEDA, introducted by Carcaterra and Sestieri) seems to be a promising approach in the mid or high frequency range to eliminate this upper frequency limit. This can be done because CED analysis solves for a smooth or low frequency transformed displacement variable from an accordingly transformed partial differential equation. A drawback for future applications in the original CED analysis is the fact that it is limited to undamped deterministic vibrations. This paper addresses the specific problems that have been solved for application of the CED analysis to both damped high frequency vibrations in two point boundary value problems as well as the implementation for damped FEM calculations.

109 Click here to view scanned manuscript ICSV5 Paper Abstract Finite Element Analysis of Gears in Mesh Authors: Seney Sirichai, Curtin University of Technology, ( Australia) Ian Howard, Curtin University of Technology, ( Australia) Laurie Morgan, Curtin University of Technology, ( Australia) Kian Teh, Curtin University of Technology, ( Australia) Volume 2, page 869, paper no. 264 Abstract: This paper presents a finite element analysis of two spur gears in mesh. The model predicts the torsional mesh stiffness of the two gears in mesh when one of the gears is restrained from rotating, with the other gear having a torque input load. The mesh stiffness of two gears in mesh varies with the meshing position as the teeth rotate within the mesh cycle and the resulting torsional stiffness decreases and increases dramatically as the meshing of the teeth change from the double pair in contact to the single pair of teeth in contact and vice-versa. The accuracy of finite element modelling of contact problems depends on the choice of the penalty parameter for the contact element. For modelling of gear teeth in mesh, the penalty parameter also varies as the gear teeth rotate through the cyclic mesh. This paper presents a simple strategy of how to determine an appropriate value of the penalty parameter as the gears rotate through the mesh cycle. The resulting torsional stiffness is predicted as a function of the position of the mesh point in the mesh cycle. The results which are presented show evidence of a change in the torsional stiffness during the double pair of teeth in contact.

110 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Radiation From Finite Length Cylindrical Shells Using Boundary Element Method Authors: Chong Wang, Australian Defence Force Academy, ( Australia) Joseph C.S. Lai, Australian Defence Force Academy, ( Australia) Volume 2, page 877, paper no. 235 Abstract: The acoustic radiation from circular cylindrical shells is of fundamental and applied interest. In previous studies of the subject, cylindrical shells are categorised into thin, and thick shells in terms of the ratio of the ring frequency fr to the critical frequency fc , i.e. fr/fc<1 for thin shells, and fr/fc>1 for thick shells. For thin shells, it has been found analytically that the radiation efficiency of cylindrical shells has a peak at the ring frequency, and above the ring frequency, the shells would behave like flat plates. For thick shells, however, the behaviour is not fully understood because it is difficult to carry out an analytical analysis especially for finite length cylindrical shells. In this paper, the radiation efficiency of a thick circular cylindrical shell with finite length has been examined by calculations using the boundary element method for three different boundary conditions, and by conducting experiments using point excitation with the boundary conditions being free at both ends. Both the numerical and experimental results indicate that the radiation efficiency attains a value of unity at frequencies well below the critical frequency. Analysis has been made to explain the behaviour of thick shells.

111 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Pressure Levels Evaluation of a Compressor by BEM Method and Comparison with Experimental Mea- surements Authors: Enrico Gargano, Instituto di Tecnologie Industriali e Automazione, ( Italy) Alessandro Bartolini, ITIA - CNR, ( Italy) Volume 2, page 885, paper no. 59 Abstract: The study of acoustic fields is becoming very important for industrial design: in fact it allows to predict the emitted noise levels of a source and to correlate them to the vibrations that are the origin of acoustic phenomena. In such way we have the possibility to make structural changes during the design of a product to decrease the noise level. In our paper we have considered as noise source an air compressor and we have utilized the boundary element method (BEM) to study the acoustic field behaviour produced in nearby field; let us suppose as condition that the normal component of particle velocity of fluid equals the normal component of vibrational velocity of structure surface. After a preliminary survey of correlation between noise and structural vibration autospectra we have choosen meaningful frequencies utilized for the experimental check of sound pressure levels detected on a reference plane 0.5 meter far from the superior surface of the air compressor.

112 Click here to view scanned manuscript ICSV5 Paper Abstract Equations in a Mixed Representation and a New Formu- lation by Finite Elements and Boundary Elements for the Resolution of a Vibro-acoustic Problem in the Pres- ence of Non-uniform Mean Flow Authors: Mabrouk Ben Tahar, Universite de Technologie de Compiegne, ( France) Eugenie Goy, Universite de Technologie de Compiegne, ( France) Volume 2, page 893, paper no. 5 Abstract: One of the most important question arises when studying the vibro-acoustic phenomenon in the presence of non uniform mean flow is the justification of the boundary conditions at the structure-fluid interface. Primarily, we are presenting the linear acoustic equations in a mixed representation for a heterogeneous moving medium and associated boundary conditions. In the mixed representation, the equations verified by Lagrangian perturbations are written in Eulerian variables in association with mean flow of the medium concerned. The choice of this approach allows us to represent - in the sense of distribution theory - the acoustic field equations provided that one uses normal acoustic displacement continuity, and to deduce boundary conditions at the interface between two moving media. Secondly, we are proposing a new formulation for the elasto- acoustic coupling problem using the previous results. In this approach the acoustic domain is divided in two sub-domains : 1- where the flow of fluid coupling fluid- is non uniform and discretised by finite elements, 2-bounding the first domain and where the flow is supposed to be zero- is discretised by boundary elements. The coupling of these two domains is obtained by applying the condition of continuity of acoustic displacement. The association of functional structure, discretised by finite element, gives us the final vibro-acoustic system to solve.

113 Click here to view scanned manuscript ICSV5 Paper Abstract Some Recent Advances in Signal Processing for Vibra- tion Monitoring Authors: Joseph Mathew, Monash University, ( Australia) Volume 2, page 903, paper no. 555 Abstract: Vibration condition monitoring is now a well accepted part of an eﬀective plant-wide condition monitoring program. Several techniques have been developed in recent years to assist vibration engineers detect and diagnose faults in machinery (Mathew 1987). This paper is concerned with two of these newer techniques, viz, the application of chaos theory and neural networks to vibration monitoring. The article is presented in two parts; Part I is concerned with chaos theory and Part II describes an application of neural networks to rolling element bearing fault diagnosis.

114 Click here to view scanned manuscript ICSV5 Paper Abstract Gear Fault Detection Parameters Development Based on Modulation Techniques Authors: G. Krishnappa, Integrated Manufacturing Technologies Institute, ( Canada) Volume 2, page 919, paper no. 384 Abstract: Vibration analysis techniques are frequently employed to detect faults in mechanical components. The amplitude and phase modulation analysis techniques can be used to detect the faults in rotating machinery components, which include bearings and gears. This paper discusses the development of several parameters based on amplitude and phase modulations and their applications to detect faults in helicopter transmissions. The parameters based on amplitude modulations, absolute measure of the percentage modulation of the amplitude envelop, negative peak taunt to measure the number of times the envelop modulated and kurtosis of the envelop. The phase modulation parameters include, percentage modulation of phase, kurtosis of wrapped and unwrapped phase and kurtosis of the ﬁrst derivative of phase modulations. The vibration data collected from the endurance test runs of OH-58A helicopter transmissions were examined to validate the eﬀectiveness of these modulation parameters in detecting both incipient and advanced faults. Using a combination of these parameters, most of the faults were detected.

115 Click here to view scanned manuscript ICSV5 Paper Abstract Dynamic Behaviour of an Aircraft Power Take-Off Shaft Drive-System Authors: Brian Rebbechi, Department of Defence, Australia, ( Australia) Volume 2, page 927, paper no. 523 Abstract: Aircraft power take-off shafts operate at high speeds and in a difficult operating environment. This paper describes the results of an investigation into the dynamic behaviour of the F/A-18 Aircraft Mounted Accessory Drive gearbox drive system. The investigation was carried out to determine the cause of failure of the input bearing in this gearbox. Measurements of gearbox vibration and shaft dynamic orbits were carried out to determine the origin of the high dynamic loads, and to evaluate the system critical speeds. These measurements indicate that the system behaviour was determined by a large initial unbalance due to component clearances, and a dynamic magnification due to the proximity of running speed to the system critical speed. Possible system improvements and proposals for design changes are discussed, as are ways to provide an interim alleviation of the problem.

116 Click here to view scanned manuscript ICSV5 Paper Abstract Predictive Maintenance of Rotating Machinery in NPP "PAKS" Based On Vibration Diagnostic Expert System Authors: Istvan Nagy, Hungarian Academy of Science, ( Hungary) Volume 2, page 937, paper no. 506 Abstract: A recent study of the Predictive Maintenance Program for approximately 300, different types of rotating machinery in NPP Paks is reviewed. The program is based on an automated vibration analysis expert diagnostic system. The data measurement and evaluation methods, the fault identification accuracy, the expert system analysis steps and the rule-base development techniques are reviewed. The process of order normalization of vibration data, the accumulation of average data as a baseline for automated analysis, the cepstrum analysis for bearing wear detection are presented. The fundamental assumption used in expert system is that the health of the machine as a whole can be assessed by isolating the spectral data pertinent to each major component. Details of machine configuration such as minor component arrangement, types of bearings, gearbox details and coupling types are stored in knowledge base via a component coding scheme. The major component groups are defined and the proper identification of the major components of a given machine and the location of the test points are shown. The method of fault diagnostics using the expert system rule-base, the fault severity assessment and fault severity trending are demonstrated through concrete practical examples of machines (motor - coupling - gearbox - coupling - pump, and high - pressure turbine - low - pressure turbine - generator, etc.) of NPP Paks.

117 Click here to view scanned manuscript ICSV5 Paper Abstract Effects of Time Delay, Order of the FIR Filter and Con- vergence Factor on Self Adaptive Noise Cancellation Authors: D. Ho, University of New South Wales, ( Australia) R.B. Randall, University of New South Wales, ( Australia) Volume 2, page 945, paper no. 495 Abstract: When vibration analysis is used for bearing fault diagnostics in gearboxes, the accelerometer measures both bearing vibration and extraneous noise which may be discrete frequency and/or random. The bearing vibration appears in the spectrum as broadband frequency components because of its random-like characteristics and these may be masked by the gearmesh frequencies and their sidebands which are more discrete than the bearing components. In such cases a signal processing technique called "Self Adaptive Noise Cancellation" (SANC) may be used to separate the discrete and random-like vibrations. However the performance of this technique is controlled by the time delay, order of the FIR filter and the convergence factor and the optimal values for these variables depend on the particular signal. This paper presents the effects of these three factors on the performance of SANC in separating simulated gear vibration signals (discrete frequency components) from simulated bearing vibration signals (broadband frequency components).

118 Click here to view scanned manuscript ICSV5 Paper Abstract Real Time Processing of Vibration Signal With Applica- tion to Slow Running Gearboxes Authors: Krystof Kryniski, Royal Institute of Technology, KTH, ( Sweden) Volume 2, page 953, paper no. 284 Abstract: Over the past few years advances in electronics totally changed the concept of vibration monitoring. Currently available monitoring systems are capable of collecting and processing a large amount of data. It is quite obvious that the problem of today is not associated with the lack of information but with its extend. To avoid the information overload new methods need to be devised which are capable of processing the information in real time and extracting the relevant information. Presented approach promotes such a concept by introducing the design of a stand-alone monitoring device, which can be programmed to track a specific machine problem. The paper briefly reviews some elements of architecture of the TMS320C31 DSP processor, which are essential for understanding the methods used for machine fault detection and to appreciate their effectiveness. However, the major part of the work is focused on monitoring and processing methods devised for detecting cracks in the meshing zones of slow running gearboxes and to monitor their growth. Additionally,the concept presented is discussed with reference to monitoring a planetary gearbox.

119 Click here to view scanned manuscript ICSV5 Paper Abstract Wear Detection in Turning Operations Using Neural Net- works Authors: A. Ghasempoor, Queen’s University, ( Canada) Thomas N. Moore, Queen’s University, ( Canada) J. Jeswiet, Queen’s University, ( Canada) Volume 2, page 961, paper no. 154 Abstract: On-line wear detection in turning operation is considered in this paper. A wear monitoring system based on hierarchical neural networks is suggested for this purpose. The changes in cutting force components are used for monitoring three wear components. The hierarchical neural network structure uses multilayered, feedforward, static and dynamic neural networks as specialized subsystem for each wear component to be monitored. Simulation studies are performed to investigate the overall suitability of the system.

120 Click here to view scanned manuscript ICSV5 Paper Abstract Mechanical Signature Enhancement of Response Vibra- tions in the Time Lag Domain Authors: Yujin Gao, University of New South Wales, ( Australia) Robin Ford, University of New South Wales, ( Australia) R.B. Randall, University of New South Wales, ( Australia) Volume 2, page 969, paper no. 498 Abstract: Signature analysis deals with the extraction of information from measured signal patterns and this paper proposes a new procedure to enhance the mechanical signature related to a faulty element in a rotating machine. The enhancement operation is implemented in the time lag domain using envelope signals which are obtained using a multiple carrier amplitude demodulation technique. This procedure is studied theoretically. Also it is evaluated using simulated digital sequences and vibration measurements from a railway track and a paper machine.

121 Click here to view scanned manuscript ICSV5 Paper Abstract Use of Directional Spectra of Vibration Signals for Di- agnosis of Misalignment in Rotating Machinery Authors: Chong Won Lee, Korea Advanced Institute of Science and Technology, ( Korea) Yun Sik Han, Korea Advanced Institute of Science and Technology, ( Korea) Young Seob Lee, Korea Advanced Institute of Science and Technology, ( Korea) Volume 2, page 977, paper no. 407 Abstract: In this paper, a new vibration signal processing technique is applied to a laboratory rotor system for characterization of its misalignment. This technique utilizes the directional spectra of the complex- valued vibration signals measured from two vibration transducers, placed perpendicular to each other. The directional power spectrum preserves the important directivity and shape information of whirling orbits, whereas the phase of the directional cross-spectrum indicates its inclination angle. Experimental results support that the directional power- and cross-spectra can be eﬀectively used for diagnosis of the misalignment in test rig.

122 Click here to view scanned manuscript ICSV5 Paper Abstract Bearing Diagnostics Based on Pattern Recognition of Statistical Parameters Authors: Fengfeng Xi, Integrated Manufacturing Technologies Institute, ( Canada) Q. Sun, University of Calgary, ( Canada) G. Krishnappa, Integrated Manufacturing Technologies Institute, ( Canada) Volume 2, page 985, paper no. 356 Abstract: In this paper a new method is proposed to diagnose bearing defects based on pattern recognition of statistical parameters. This pattern recognition problem is described as transformations from the pattern space to the feature space and finally to the classification space. Based on trend analysis of various statistical parameters, four parameters Peak, RMS, CrestFactor and Kurtosis are selected to form a pattern space. A feature space is then formulated by a nonlinear transformation end its dimension is defined as two, for the purpose of displaying the results on the 2-D plane. Then, through a linear transformation a classification space is formed on which the data of different bearing defects can be clustered in different regions. Classification of bearing defects is done by the discriminan t function which is generated through a lemming process. The discriminant function can relate the different bearing defects to the different regions in the classification space. The proposed method is tested to diagnose the bearings with seeded defects and the results show that it is an effective method.

123 Click here to view scanned manuscript ICSV5 Paper Abstract From Vibration Monitoring To Acoustic Signature Mon- itoring of a Ship Authors: Bernard Garnier, METRAVIB RDS, ( France) D. Vaucher de la Croix, METRAVIB RDS, ( France) D Webster, Pacific Noise and Vibration, ( Australia) Volume 2, page 993, paper no. 291 Abstract: Very quiet ships are now built not only for military purposes (minehunters, ASW frigates, submarines, but also for oceanography and fishery research. It is proven that fishing boats could catch more fish schools if they were quieter. However, the perfect vibro-acoustic control achieved by a careful design, the systematic introduction of rubber isolators, the use of large amounts of sound and vibration absorbing coatings and sound proofing materials is a costly investment to maintain. As organizing adequate sea trials for measuring the ship radiatcd noise is very demanding - and sometimes even impossible if the vessel is quiet and the sea noisy - the only realistic solution for controlling periodically, or even better permanently, the vessel signature is to reconstruct it from on-board measurements. Practical seaproven strategies for evaluating the sound radiation of a complete vessel from hull vibrations (accelerometers), machinery vibration (accelerometers), and machinery noise (microphones) will be presented. A sufficient emphasis will be given to the delicate balance between a machine per machine monitoring philosophy (already widely used for machinery health monitoring in industrial plants), and a global approach of the vessel as an integrated system. Another point to be presented with some details is the difficult task of data reduction - it is easy to see that processing at several kilohertz several dozen of sensors brings to handle megabits per second of raw data, when the final answer to provide relates to a binary question: is my instant signature OK? Specific system architectures can help to solve this difficulty, intrinsic to any dynamic monitoring system. Last but not least, the major issue of such a system is the acoustic calibration, i.e, the proper sensors localization strategy and associated database providing the solution for estimating the radiated signature from onboard measurements. An original holography technique is recommended and will be presented in a companion paper.

124 Click here to view scanned manuscript ICSV5 Paper Abstract Frequency Analysis for Turbomachinery with Journal Bearings Authors: Ian Howard, Curtin University of Technology, ( Australia) Adem Omerovic, Curtin University of Technology, ( Australia) Laurie Morgan, Curtin University of Technology, ( Australia) Volume 2, page 1001, paper no. 269 Abstract: Journal bearings are used extensively on small and large turbogenerator units in the process and power generation industries. The ability to predict the condition of the rotor system using proximity probe measurements of the shaft motion in two orthogonal planes can lead to a reduction in maintenance costs and can also improve the operational safety of the high speed rotating machines. The output signals from the proximity probes are typically used to produce orbit plots representing machine shaft centre line motion which can be used as an indicator of general machine condition as well as for detecting speciﬁc machine malfunctions. This paper presents an introduction to the frequency analysis techniques which relate speciﬁcally to turbomachinery with journal bearings. It is shown how the complex discrete Fourier transform of the orthogonal orbit shaft motion produces the full asymmetrical spectrum, which further leads to the concepts of forwards and backwards shaft whirl. The full spectrum can be used on run up and run down tests to highlight changes in the dynamic amplitude and phase motion of the shaft and is a very useful diagnostic tool for turbomachinery. The techniques are illustrated by experimental examples.

125 Click here to view scanned manuscript ICSV5 Paper Abstract The Application of the Block Vibration Characters of the IC Engines with The Fault Compressing Rings Authors: Y Zhang, Changsha Communications Institute, ( China) Z. P. Zhang, Changsha Communications Institute, ( China) Y.C. Zhou, Wuhan Transportation University, ( China) Volume 2, page 1011, paper no. 253 Abstract: In this paper, the principle to diagnose the fault compressing rings with the block vibration signal is analyzed by considering of the excitation resources, the excited objects and the drift process of the rings: the equation to calculate the rings nature frequency in the cylinder is given; the simulation tests of the fault ring diagnosing are carried out by the two types of the diesel engines. The tests results coincide with the values obtained from theoretical calculation in trend, therefore the method to diagnose the fault compressing rings by the block vibration signal is got: In the domain of the low frequency of the block vibration signal there is a characteristic frequency which is closed to the single rings nature frequency in the cylinder, the PSD value at the characteristic frequency is grown, in the narrow frequency band including to the characteristic frequency the power value is grown obviously, then we can believe that there are fault compressing rings (usually it is the ﬁrst ring).

126 Click here to view scanned manuscript ICSV5 Paper Abstract Diagnosis for Radial Rolling Contact Bearing Using Acous- tic Emission Technique (1st Report): Acoustic Emission Source Location Method Authors: Takeo Yoshioka, Mechanical Engineering Laboratory, ( Japan) H Mano, Tokyo University of Agriculture and Technology, ( Japan) Volume 2, page 1017, paper no. 251 Abstract: This paper describes the principal of an acoustic emission source location method for a radial rolling bearing and proof of the location method. The method locates contact points between balls end an inner ring or an outer ring within a loading zone of a radial rolling bearing under a radial load at the moment of acoustic emission generation as possible acoustic emission sources. The location result is shownas a histogram which has several peaks and is symmetrical at the highest peak after locating repeatedly. In the location result the X-axis shows the position on a raceway of the inner race or outer race, the Y-axis is the number of acoustic emissions. The position of the highest peak agrees with the position of the actual acoustic emission. The principal of the location method was proven by rolling contact fatigue tests of radial roiling bearings under a radial load. The location system was comprised of acoustic emission measurement equipment and position detectors of the inner race and the balls. The AE sensor and the detected sensors were ﬁxed on the housing of the test bearing. The locator in the system decided the source position of acoustic emissions under signals from the equipment and the detectors. The located positions indicated by the method agreed with the positions of spallings. It was conformed in the rolling contact fatigue tests that acoustic emission was caused by propagation of rolling contact fatigue crack and occurred before the generation of spalling.

127 Click here to view scanned manuscript ICSV5 Paper Abstract Dynamic Load Identification in Gear Wheels on the Ba- sis of Vibroacoustic Measurements Authors: Andrzej Wilk, The Silesian University of Technology, ( Poland) Volume 2, page 1025, paper no. 238 Abstract: Tooth working surfaces wear in wheels and other transmission elements at work increases dynamic loads. Optimum symptoms of dynamic load changes were sought for diagnosing in the elaboration. Simulating examinations of gear wheels with spur or helical teeth were carried out. Non-linear dynamic models of a pair of gear wheels were chosen as the basis of examinations. Their changing stiffness meshing, interteeth backlash and teeth errors were taken under consideration. It has been established that there is a linear dependence between (Ku-1=Pd) additional dynamic load and the effective value of circumferential vibration accelerations of wheels. Vibration measurements, most frequently for selected points of housing, are carried out in industrial gear weels. The examination of a pair of gear wheels working at circulating power system of the test stand were carried out. Circuit vibrations of rotating gear wheels and those of selected points of the housing were measured and analyzed simultaneously at the test stand by piezoelectric transducer. Marginal correlation between non-filtrated effective values of vibration in transmission housing and circumferential vibrations of gear wheels has been observed. The correlation has increased significantly after selecting the housing vibration signal. This selection eliminated the dominating frequencies of free vibrations in the measured points.

128 Click here to view scanned manuscript ICSV5 Paper Abstract The Diagnosis of Bearing Defects Using Synchronous Autocorrelation Technique Authors: Wen Yi Wang, Monash University, ( Australia) Volume 2, page 1033, paper no. 236 Abstract: In the diagnosis of rolling bearing defects, the envelope spectrum technique is regarded as an effective method. Ensemble averaging of envelope spectra can be used to further enhance the detectability of the technique. However, in cases where signal-to-noise-ratio (SNR) is poor, the inherent non-linearity of the enveloping process limits the effectiveness of this technique. In this paper, the synchronous autocorrelation technique is proposed to detect bearing defects under poor SNR conditions. The idea comes from the synchronous demodulation of amplitude modulation (AM) signals in communication systems. Using this technique, the original vibration signal is first bandpassed at a chosen high frequency resonance to produce the impulsive AM signal related to faulty bearings. The instantaneous angle information of the AM carrier is identified using Hilbert transform and the AM signal is then synchronously demodulated. The resulting signal may be resampled at a lower rate if required and then autocorrelated. Because this technique only involves linear operation, the signal identity should be maintained regardless of the noise level. Ensemble averaging can also be used to improve the autocorrelation estimate. Finally, the defect period will be identified in the autocorrelation function. The effectiveness of the synchronous autocorrelation technique is demonstrated in this paper using both numerical and experimental data. It is found that the synchronous autocorrelation technique provides good results for a SNR of -11dB.

129 Click here to view scanned manuscript ICSV5 Paper Abstract Diagnostics of Gears Using Higher Order Spectral Anal- ysis Techniques Authors: Stanislaw Radkowski, Warsaw University of Technology, ( Poland) Volume 2, page 1041, paper no. 197 Abstract: The work undertakes an issue of estimating and predicting the level and structure of the vibroacoustic signal generated by a pair of toothed wheels and propagated by the structure of the gears housing. Tak- ing into account the existence of a number of internal disturbances in a toothed gear, apart from the external ones, we have built a model of generation of a disturbed vibroacoustic signal which refers to the friction power. Assuming that the basic role in transmission of such diagnostic information is played by the phenomena of amplitude and phase modulation of the vibroacoustic signal, the author points to the significance of the signals non-linear components. For that reason in this work a model of signal in the form of a Volterra series is assumed, which enables examination of the influence that disturbances have upon non-linear components, and assessment the technical condition of the assembly based on the results from demodulation of choosen frequency bands. At the same time, utilizing the higher - order spectral analysis method, a procedure to determine the changes in the spectrum structure caused by a local failure was developed. Additionally, the author took into account the precision of manufacturing of toothed wheels and the influence that operating wear and tear of individual elements of a unit has upon variations of the general vibroacoustic activity. In the final part of the work is presented an algorithm of simulation of signal generation that accounts for the effect of apparent interference of teeths flexibility, for the related disturbances of contact (too early and too late contact) in the dynamic model, and for the changes of period of meshing and contact, as well as for the related phenomenon of amplitude and phase modulation in the kinematic model.

130 Click here to view scanned manuscript ICSV5 Paper Abstract A Study on the Fracture of a Sirocco Fan Impeller Authors: Seung P. Lee, LG Electronics Inc, ( Korea) C.O. Ahn, LG Electronics Inc, ( Korea) H.S. Rew, LG Electronics Inc, ( Korea) S.C. Park, LG Electronics Inc, ( Korea) Y.M. Park, LG Electronics Inc, ( Korea) D.I. Rhee, LG Electronics Inc, ( Korea) Volume 2, page 1049, paper no. 123 Abstract: A sirocco fan, as a compartment of a window type room air conditioner, has been used in the indoor part to suck the warm room air and to blow the chilled air into the room. Because the air conditioner goes on and oﬀ according to the room termperature repeatedly, the sirocco fan also repeats its drive and repose action as long as the air conditioner operates. And since a sirocco fan usually has been made by engineering plastic, it is tend to deform and crack easily as comparing with the metals. Thus, there are possibilities of the fracture by the periodic loading, fatigue, and natural frequency. To understand the mechanism of failure in a fan, we chose a kind of sirocco fan and experimented. After 150 days continuous operation, we could see the cracks. To check the possibilities of the failure due to the periodic loading and resonance, both numerical and experimental approaches were carried out. In case of fatigue, numerical method based on F.E.M. is applied. Based on von Mises failure criterion, we can conclude that the sirocco fan is safe in case of the fatigue. And the other possibility is the resonance between a natural frequency and the aerodynamic force. Experiment is performed to see the natural frequency and numerical method based on the V.E.M. is applied. The numerical calculation is going on. In this paper, the details of calculation results will be included and discussed.

131 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Review and Prospects of Intelligent Diagnosis Technique for Spacecrafts Authors: Wenhu Huang, Harbin Institute of Technology, ( China) Xuexiao Wang, Harbin Institute of Technology, ( China) Xinwei Jiang, Harbin Institute of Technology, ( China) Volume 2, page 1057, paper no. 84 Abstract: In this paper the failure records of spacecrafts over the world are reviewed to conﬁrm the urgency of the diagnosis of faults. The special features of the dignostic technology for a spacecraft are discussed, and accordingly the problems of diagnostic technology for a spacecraft system are reviewed and prospected such as: the strtegy and architecture of the intelligent diagnostic system, the hierarchical structure of the knowledge model, the inexact reasoning and heuristic reasoning, the distributed diagnostic technology and so on. Finally, the prospects of the intelligent diagnosis technique for a spacecraft are reviewed.

132 Click here to view scanned manuscript ICSV5 Paper Abstract Simulating Examinations of Vehicle Suspensions With Non-Linear Damping and Rigidity Characteristics Authors: Janusz Gardulski, The Silesian University of Technology, ( Poland) Volume 2, page 1065, paper no. 58 Abstract: Mathematical model of suspensions together with its geometrical dimensions hasbeen presented in this paper. It is a 6 mass discreet dynamic system with 36 freedom grades. Its concentrated masses are connected by elastic and attenuating elementsof non-linear characteristics. Apart from springs and silencers there are also wheel guiding elements ( rookers, Iateral control rods). The model is activated to vibrations by road unevenness. Input functions are of stochastic nature. Changes of many element parametres of the model were taken under consideration in simulating examinations (type of suspension, mass distribution, stiﬀness and attenuation characteristics changes, etc.). The results were presented in a graphic form together with comparative analysis.

133 Click here to view scanned manuscript ICSV5 Paper Abstract Simulation of Low Shaft Speed Bearing Faults Under a Heavy Load Authors: Yu-Fang Wang, Australian National University, ( Australia) Peter J. Kootsookos, MV Technology Ltd., ( Ireland) Volume 2, page 1073, paper no. 234 Abstract: In this paper, a general model of the signal from faulty rolling element bearings under the condition of a heavy load is given. The envelope-autocorrelation of this proposed model in the case of very low shaft speed is given with a mathematical description. The simulated signals of rolling element bearings under the condition of a heavy load with inner race fault, outer race fault, and roller fault are generated using the model. In the power spectrum of signals, the characteristic frequency and its harmonics are submerged in the white noise, but they are obvious in the envelope-autocorrelation and envelope- autocorrelation power spectrum. It is demonstrated that the envelope-autocorrelation and its power spectrum are eﬀective as to a fault detection technique.

134 Click here to view scanned manuscript ICSV5 Paper Abstract Frequency Estimation in the Fault Detection of Rolling Element Bearing Authors: Yu-Fang Wang, Australian National University, ( Australia) Peter J. Kootsookos, MV Technology Ltd., ( Ireland) Volume 2, page 1081, paper no. 295 Abstract: Faulty rolling element bearings under very low shaft speed and light load exhibit vibrations which possess periodic envelope-autocorrelations. The main frequencies of this envelope-autocorrelation are the fault characteristic frequency and its harmonics. In this paper, one of the improved Notch Filtering Techniques with a designed ﬁlter is used to estimate the fault characteristic frequency and its harmonics. The designed ﬁlter is used to remove the estimated frequency. With this technique, the fault characteristic frequency and its harmonics can be accurately estimated.

135 Click here to view scanned manuscript ICSV5 Paper Abstract Frequency Domain Dynamic Analysis of Systems With Viscous and Hysteretic Damping Authors: F. Venancio-Filho, Federal University of Rio de Janeiro, ( Brazil) Volume 2, page 1091, paper no. 542 Abstract: This paper introduces initially a general formulations for frequency-domain dynamic and vibration analysis using discrete Fourier transforms through the Implicit Fourier transform concept. The issues of treatment of initial conditions in the frequency-domain and convergence are analysed. An eﬃcient iterative method for the frequency domain dynamic analysis of MDOF systems and a method for analysis of nonlinear systems are introduced.

136 Click here to view scanned manuscript ICSV5 Paper Abstract Active Constrained Layer Damping on Cylindrical Shells Authors: Kam W. Ng, Office of Naval Research, ( U.S.A.) Volume 2, page 1103, paper no. 157 Abstract: Vibration of finite cylindrical shell was controlled using active constrained layer damping technique. In active constrained layerdamping, a visco-elastic damping layer is sandwiched between two piezo-electric layers to provide built-in sensing and control capabilities that actively tune the shear of the visco-elastic layer, in response to the structural vibrations. The sensing, as indicated by the sensor voltage Vs, is provided by the piezoelectric layer which is directly bonded to the structure. The actuation is generated by the other piezo-electric layer which acts as an active constrained layer that is activated by the control voltage Vc. Specifically, two damping patch configurations at various locations were tested and evaluated. Results showed that the rectangular damping patches bonded on the end cap are more effective than the triangular patches bonded to the free end of the cylinder. Performance of the combination of two and more patches is similar to the single patch. Overall results showed that the active constrained layer is viable and has greater vibration suppression than the passive constrained layer damping. To improve the active constrained layer technique, there is a need for high force and high displacement actuators, and more robust controllers.

137 Click here to view scanned manuscript ICSV5 Paper Abstract Dependence of Active Damping Ratio to Feedback Gain and Stiffness in Vibration Control of Smart Structures Authors: Hyun Chul Park, Pohang University of Science and Technology, ( Korea) Young Kyu Kang, Pohang University of Science and Technology, ( Korea) Volume 2, page 1109, paper no. 261 Abstract: Interaction between the structure and the control is investigated numerically and verified experimentally for the active vibration control of carbon/epoxy laminated composite beams with collocated piezoceramic sensors and actuators. Finite element method is used for the analysis of dynamic characteristics of the laminated composite beams with and without the piezoceramic sensors/actuators. Damping and stiffness of the adhesive layer and the piezoceramics are taken into account in the finite element modeling. Tailoring that varies the stiffness and the damping properties of the laminated composite beam is used with stacking sequence of [ 4/O2/902] , where 0, 15, 30, 45, 60, 75 and 90 degree. Optimal s = control theory is applied for the analysis of control characteristics of the beam. Experiments on the active vibration control of the laminatedΘ composite beamsΘ has been carried out by making use of direct negative velocity feedback with constant gain. Active and passive damping ratios and modal damping of the first bending of the beams are measured experimentally. They are in good agreement with those of the finite element analysis. When the feedback gain is small, the active control follows trends of the passive control but adds additional effects due to the active control. But for large feedback gains, the active control is dominant over the passive control. The active control is more effective to the structure with higher stiffness than to the structure with lower stiffness, when the feedback gain is large.

138 Click here to view scanned manuscript ICSV5 Paper Abstract Impact Damper with Granular Materials for Multibody System Authors: Isao Yokomichi, Kitakyushu College of Technology, ( Japan) Masaharu Aisaka, ISUZU Motors Limited, ( Japan) Yoshiaki Araki, Kyushu Institute of Technology, ( Japan) Volume 2, page 1117, paper no. 249 Abstract: A shot impact damper consists of a bed of granular materials moving in a container mounted on a multibody vibrating system. This paper deals with the damping characteristic of a multi-degree-of- freedom (MDOF) system that is provided with the impact damper when the damper may be applied to any point of the system. In the theoretical analysis, the particle bed is assumed to be a mass which moves unidirectionally in a container, and collides plastically with its ends. Equations of motion are developed for an equivalent single-degree-of-freedom (SDOF) system and attached damper mass with use made of the normal mode approach. The modal mass is estimated such that it represents the equivalent mass on the point of maximum displacement in each of the vibrating modes. The mass ratio is modified with the modal vector to in-clude the effect of impact interactions. Results of the analysis are applied to the special case of a three-degree-of freedom (3DOF) system, and the effects of the damper parameters including mode shapes and damper location are determined. Numerical and experimental studies are made of the damping performance of plural dampers located at selected positions throughout a multibody system. The impact vibration model, including the motion forms comprising riding or separation of damper masses on individual vibrating bodies is developed, and the resulting formulation is analyzed by using the modal synthesis method. For n degree-of-freedom system, the existence of as many as 2n combinations of motion forms are identified through digital simulation. Results of numerical studies were compared to, and were found to be in good agreement, with experimental results. It is found that the shot impact damper with properly selected mass ratio and with container clearance effectively suppresses the resonance peaks over a frequency range.

139 Click here to view scanned manuscript ICSV5 Paper Abstract Informative Guidelines for the Assessment of Noise An- noyance Authors: Louis A. Challis, Challis and Associates Pty Ltd, ( Australia) Volume 3, page 1127, paper no. 491 Abstract: The Standards Committee, AV5 recently revised the presentation of an informative guideline for the assessment of environmental noise annoyance. This paper reviews the 25 years of statistical analyses from which the tabular percentile levels presented to the committee were derived.

140 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract An Overview of Environmental Noise Legislation Through- out Australia Authors: Marco Ciccozzi, South Australian Environmental Protection Authority, ( Australia) Tony Circelli, South Australian Environmental Protection Authority, ( Australia) Richard French, South Australian Environmental Protection Authority, ( Australia) Volume 3, page 1135, paper no. 557 Abstract: Australia is made up of a number of different states and territories. Each of these have their own govern- ments which administer environmental noise policy. Historically there has been very little coordination or collaboration between the states to ensure a consistency of approach to such issues. For many years there was a group made up of environmental officers from most of the states that met on a regular basis. This group did achieve some good results in terms of rationalising research and the labelling of noisy equipment such as air conditioners, however it was disbanded just at the time when it was about to get stuck into the issues of uniformity between the states. As a result we have a situation where environmental noise is assessed in many different ways and by different agencies within each state or territory. Most states or territories are currently in the process of reviewing their noise policies. There has been much greater consultation between the states and territories during the development of their new policies than there ever was in the development of the original policies. Despite this however there will still be many significant differences between the policies when they have all been finished and become operational.

141 Click here to view scanned manuscript ICSV5 Paper Abstract Experimental Studies of Sound Propagation in a Strongly Stable Atmospheric Boundary Layer Authors: Hans Olav K. Hygen, University of Bergen, ( Norway) Volume 3, page 1141, paper no. 527 Abstract: The experiment series, "Blast propagation through forest-Norwegian Trials" were carried out in a forest region at Finnskogen, Norway (N 50d 50’, E 12d 00’). Sound pressure was generated by several explosions of 1, 8, 64kg C4 explosives, which were laid out on a two-axis system, 24km by 24km in a relatively flat forest terrain. The experiment consisted of one summer and one winter part, respectively. Thus, the effects of snow cover could be observed. The main purpose of these experiments was to gain more knowledge on the relationship between meteorology and sound propagation. Meteorological data were obtained by tethered balloons, radiosondes, automatic weather stations and turbulence measurements by eddy correlation method just above tree tops. This study uses the data from one morning where there was a strong temperature inversion. From the measurements of that day horizontal homogeneity of the atmosphere was verified. The difference of sound propagation in upwind and downwind conditions quantified to about 30dB transmission loss. Variation in recordings at single microphones during this morning was about 10dB, with 50dB transmission loss as an extreme value. The study ends with some attempts of modelling the sound propagation with a raytracings model and a FFP model.

142 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Music Noise and the EPA’s Draft Guidelines Authors: Byron Martin, VIPAC Engineers and Scientists, ( Australia) Carl Q. Howard, University of Adelaide, ( Australia) Volume 3, page 1149, paper no. 493 Abstract: Acoustic measurements were taken at several existing entertainment venues to compare the noise levels with the draft guidelines suggested by the South Australian Environment Protection Authority. It is shown that the noise levels measured at the entertainment venues in the absence of music noise can exceed the criteria in the guidelines. The practicalities of the guidelines are discussed from a planning and design view point and also from a consultant’s view point.

143 Click here to view scanned manuscript ICSV5 Paper Abstract Variation of Turbulence Effects along a Propagation Path Authors: Ian Donald McLeod, Monash University, ( Australia) Charles G. Don, Monash University, ( Australia) Volume 3, page 1153, paper no. 143 Abstract: Impulsive sound is a revealing way of probing turbulent effects as changes to the pulse waveform represents the influence of the meteorological condition s over a short interval, When the wind speed is appropriately measured the propagation time can be accurately predicted, Even when a successful prediction of the pulse propagation time is achieved, efforts to quantitatively link changes in the pulse amplitude, waveform and spectrum to wind speed fluctuations have been largely unsuccessful, To be reported here are the results from a recent experiment in which four microphones, each accompanied by an anemometer, were placed 5m apart along the wind direction, The use of 5m spatial regimes allows a detail monitoring of the wind structure and the observation of progressive changes in the pulse waveform, Scattering between and from outside the line of microphones is investigated and the results are related to possible models of sound propagating in a turbulent field.

144 Click here to view scanned manuscript ICSV5 Paper Abstract Further Reduction of Construction Noise in the Com- munity Authors: Wai-Keung Wong, Environmental Protection Department, ( Hong Kong) W.K. Szeto, Environmental Protection Department, ( Hong Kong) Sam W.H. Wong, Environmental Protection Department, ( Hong Kong) Volume 3, page 1161, paper no. 120 Abstract: Noise from general construction activities in Hong Kong during restricted hours (between 7 p.m. and 7 a.m. on a weekday and at any time on a Sunday or public holiday) is controlled by means of a construction noise permit system. The contractor who wishes to carry out construction work in restricted hours has to ensure that the noise level so generated at noise sensitive receivers must be less than a set of Acceptable Noise Levels in order to obtain a permit from the Authority. Owing to the fast development in Hong Kong, complaints against construction noise are on the high side. The government has determined to further tighten up control of noise from general construction activities. As from 1.11.96, the Acceptable Noise Levels of ﬁve commonly used noisy equipment are lowered by 15 dB(A) and three type of prescribed construction work are virtually banned in high density built-up districts known as desig- nated areas. This paper describes the tightened up new control and the parallel enforcement actions. The eﬀects of the control on the construction industry are covered. To increase public awareness of their right on environmental quality and ensure compliance of the control by the industry, the Authority has provided publicity materials and established regular liaison meetings with the trade associations and private contractors.

145 Click here to view scanned manuscript ICSV5 Paper Abstract An Open Database on Propagation of Low Frequency Impulse Noise in the Atmosphere Authors: Lars Robert Hole, Norwegian Defence Construction Service, ( Norway) Robert L. Guice, Applied Research Associates, ( U.S.A.) Volume 3, page 1167, paper no. 83 Abstract: This paper describes four sound propagation experiments which were undertaken in Norway from 1994 to 1996. Trials were carried out at Finnskogen; a long range site, and at Haslemoen; a short range site. Summer and winter conditions were investigated at both sites. Two similar experiments were carried out at each site with and without snow cover. At Finnskogen, an experimental array of 24 by 24 km was set up, in a terrain with smooth hills, primarily covered by forest. At Haslemoen, propagation was investigated out to 1.5 km above a uniform forest and a uniform, flat open field of pasture land. One, 8 and 64 kg cylindrical charges of C-4 explosives were used as sound sources. Measurements of acoustics, seismic ground response, complex ground impedance and meteorology were carried out simultaneously. This paper gives an overview of the experiments and presents examples of data. Literature for further details is referred. An easily accessible database with all data will soon be available. The database will be a valuable tool for development, validation, and refinement of sound propagation models. The structure of this database is outlined.

146 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Recent Studies on Community Noise at Bahia Blanca City (Argentina) Authors: Liberto Ercoli, Universidad Tecnologica Nacional, ( Argentina) A.P. Azzurro, Universidad Tecnologica Nacional, ( Argentina) M.T. Piovan, Universidad Tecnologica Nacional, ( Argentina) A. Alvarez, Environment Direction, Municipality of Bahia Blanca, ( Argentina) J. Smael, Environment Direction, Municipality of Bahia Blanca, ( Argentina) Volume 3, page 1175, paper no. 49 Abstract: Based on the public demand through noise complaints expressed by the neighbors to the local newspa- per, radios and TV, a research project on community noise is being performed by the authors trying to find a practical methodology for the acoustic characterization of medium size cities (50,000 - 500,000 inhabitants). One of the research steps was to hold an environmental noise survey (more than 400 questionnaires were filled) in order to know the subjective opinion of the people about their neighborhood, main noise sources, level of annoyance, etc. Simultaneously, measurements were taken to objectively evaluate in- situ the actual noise levels. The present paper briefly shows preliminary resu lts on the correlation between the subjective opinions and objective measurements.

147 Click here to view scanned manuscript ICSV5 Paper Abstract Linear Response of the Cochlea Authors: David Alan Bies, University of Adelaide, ( Australia) Volume 3, page 1183, paper no. 434 Abstract: Begining with the work of Mammano and Nobili it is shown that in the passive state the cochlear partition may be modelled as an array of modally uncoupled independent mechanical oscillators. While uncoupled modally the oscillators of the cochlear partition are strongly coupled hydraulically through the forcing ﬁelds of the stapes and all other segments of the cochlear duct. Consequently, each mechanical oscillator of the cochlear partition responds modally in forced response dependent upon the motion of the stapes and the motions of all other segments of the cochlear partition. It is shown that the oscillators of the cochlear partition are linear in passive response to sound pressure levels of 110 dB re 20 uPa. Evidence is presented in support of the assumption that in the case of active response unclamping may be assumed to vary on a time scale which is long compared to the period of sound in the audio frequency range. In the latter case active response of the cochlea may also be described in terms of the same system of linear oscillators as in the passive case but with variable damping. It will be shown that the proposed active model is in good agreement with available data.

148 Click here to view scanned manuscript ICSV5 Paper Abstract Impulse Noise From Firearms Authors: Antonio Miguel Mendez, Laboratorio de Acustica y Luminotecnia CIC, ( Argentina) Edmundo Carlos Rochaix, Acoustical Consultant, ( Argentina) Volume 3, page 1195, paper no. 379 Abstract: This paper contains basic information on the acoustical environment at several stands where members of the police force perform shooting practices. The object of the study is to gather information to improve the environment in existing and future constructions. Diﬀerent types of guns where used for this study. Noise levels were recorded and analysed using instrumentation appropriated for this type of studies. The paper also includes details of the weapons used, the instrumentation and the shooting stands. Results are shown and analysed. Finally, recommendations regarding the construction of shooting stands are presented.

149 Click here to view scanned manuscript ICSV5 Paper Abstract Investigation of Subsonic Oscillations Influence on Air- craft Personnel Working Under Nervous Psychophysio- logical Overloads Authors: Michael M. Samoylov, Baltic State Technical University, ( Russia) G.M. Ponomarenko, Baltic State Technical University, ( Russia) Pavel V. Vorobjev, Baltic State Technical University, ( Russia) V.V. Zaytseva, Baltic State Technical University, ( Russia) Volume 3, page 1203, paper no. 467 Abstract: Unfavorable influence of high intensity subsonic oscillations on humans has been determined in numerous scientific researches. Elaborated by authors investigations showed that humans being under abnormally high or long nervous-psychophysiological overloads and other harmful factors significantly affect by subsonic even of low intensity. Being in a complex with other harmful factors subsonic causes such undesirable facts as delays of visual sensor reaction, enhancement of operator mistakes, space disorientation. Influence of subsonic of low intensity being together with other harmful factors especially presented in such human activity as aircraft running. This sort of human activity is characterized by near-extremal work conditions for the pilot or even for all crew when the pilot is under significant nervous-psychophysiological overloads caused by subsonic influence what may be the reason of an emergency situation. The highest levels of subsonic were fixed during flying up and landing of aircraft. Tur- bulent flows making by airflow streamlining over the chassis and wings elements are the main sources generate subsonic oscillations. Switching on of the engine reverse also gives hasty increase of subsonic level. It should be underlined that increase of subsonic level become especially dangerous during process of aircraft landing when the crew has being affected by different harmful factors, first of all by nervous- psychophysiological overloads, become being influenced by subsonic also. These situations cause quick increase of likelihood of crew actions which are not adequate to changes of flying what might be the reason of an emergency situation. Taking into account results of carried out investigations it is proposed by authors to review exist norms of subsonic for aircraft crew to make them more strict.

150 Click here to view scanned manuscript ICSV5 Paper Abstract Traceability and Uncertainty of Low-Frequency Vibra- tion Measurements Authors: Norman H. Clark, CSIRO National Measurement Laboratory, ( Australia) Laurence P. Dickinson, CSIRO National Measurement Laboratory, ( Australia) Volume 3, page 1207, paper no. 443 Abstract: Measurements of vibration in the frequency range below 20 hertz, down to 0.1 hertze or even lower, are of interest to consultants, manufacturers and researchers in such ﬁelds as ground vibration due to blast- ing, impact testing of safety equipment (eg to AS1801 or AS1698), and human exposure to vibration (eg to AS2970 or AS2973). However, many vibration transducers, and the voltmeters or recorders used with them, may give incorrect readings at these low frequencies. If such instruments have not been calibrated in this range, the reading error cannot be corrected. In some cases measurements may not be legally acceptable, if the measuring equipment has not been calibrated in such a way that the measurements are traceable to the primary units of time, length and voltage. This paper brieﬂy discusses low-frequency measurement errors and uncertainties, and the chain of traceability through calibrations performed at the National Measurement Laboratory.

151 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Sound Quality of Wind Turbines Authors: Reinhard Weber, Carl-von-Ossietzky University, ( Germany) Christoph Eichenlaub, Carl-von-Ossietzky University, ( Germany) Volume 3, page 1215, paper no. 401 Abstract: The unpleasantness of 20 s-sequences of wind turbine noises is assessed by test persons (TPs) in paired comparison experiments. Noise rankings are deduced from the TPs unpleasantness judgements as well as from the calculated parameter data and theyare analysed by several statistical methods. The unpleasantness of wind turbine noises is estimated very similar by a large group of TPs. For the objective description of the noises psychoacoustical parameters are calculated. The judgement behaviour of the TPs ts very well to the rankings which have been computed for the psychoacoustic parameters, tonality and uctuation strength.

152 Click here to view scanned manuscript ICSV5 Paper Abstract Relation Between TRICC and Sound Image Perception in a Sound Field with a Single Echo Authors: H. Yanagawa, Chiba Institute of Technology, ( Japan) Tetsuo Tagaeto, Kogakuin University, ( Japan) H. Komatsu, Kogakuin University, ( Japan) Volume 3, page 1223, paper no. 377 Abstract: Analysis of the hearing characteristic and evaluation of sound ﬁelds are important if we want to reproduce a spatial impression of sound ﬁelds. To estimate the quality of the sound image and spatial impression, we use a burst white noise signal as a ation and the time window length used for TRICC analysis including the onset of sound.

153 Click here to view scanned manuscript ICSV5 Paper Abstract Finite-Element Method Analysis of the Normal and Re- constructed Middle Ear Authors: Takuji Koike, Tohoku University, ( Japan) Hiroshi Wada, Tohoku University, ( Japan) Toshimitsu Kobayashi, Nagasaki University School of Medicine, ( Japan) Volume 3, page 1231, paper no. 362 Abstract: Many middle ear prostheses are available for reconstruction of a missing or damaged ossicle. However, there are few studies, which investigate the acoustic properties of these prostheses, and the information that could lead to the design and development of better ossicular replacement prostheses is absent from the report. Clinical trials comparing many prostheses would be the best method of analysis, but these are difficult to perform and are contaminated by a large number of variables that are hard to control. Therefore, some experiments with ossicular substitution in animals and human temporal bones have been performed. However, animal studies are not very good for acoustic studies because of the anatomic differences, and the specimen is difficult to handle. In this study, three-dimensional finite- element models of a human intact middle ear and reconstructed middle ears using many types of incus replacement prosthesis are established. Then, an attempt is made to clarify the optimum method for reconstructing the middle ear.

154 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract The Significance of the Vibration Direction for the Sub- jective Evaluation of Dual-axis Whole-body Vibrations Authors: Barbara Griefahn, University of Dortmund, ( Germany) Peter Broede, University of Dortmund, ( Germany) Wolfgang Jaschinski, University of Dortmund, ( Germany) Volume 3, page 1239, paper no. 258 Abstract: Sixteen female and fifteen male subjects, 19-51 years of age participated in the present study. Its purpose was to determine various combinations of sinusoidal simultaneously presented (dual-axis) vertical and lateral whole-body vibrations that are sensed as equally strong as a preceding single-axis reference (aw = 1.25 ms-2 r.m.s.) which was applied in either of both directions only and which had the same frequency, namely 1.6, 3.15, 6.3 or 12.5 Hz. The test motion consisted of a constant predefined and a variable component. The first was applied in the same direction and with either of 5 predefined percentages of the acceleration of the reference (10, 25, 50, 75, 90%). The variable component was perpendicularly oriented to the first (resp. to the reference); its magnitude was varied by the subjects until the dual-axis test signal was judged as equally strong as the single-axis reference. The curves of equally sensed combinations determined for the 4 frequencies were bended right-downwards as expected due to ISO/DIS 2631. But there were remarkable quantitative discrepancies for frequencies above 1.6 Hz with an underestimation of lateral vibrations; the factor ky being 1.5 - 1.9 greater than in the standard. It is concluded that the weighting factors for lateral vibrations above 1.6 Hz need to be corrected for the proper evaluation of discomfort caused by multi-axis whole-body vibrations.

155 Click here to view scanned manuscript ICSV5 Paper Abstract Low Frequency Noise in Domestic Environment: Mea- surement Results and Assessment of Annoyance Authors: Marianna Mirowska, Building Research Institute, ( Poland) Volume 3, page 1247, paper no. 147 Abstract: The appliances installed in the residential buildings such as transformers, air-conditioners, freezers are often sources of low frequency noise. Although sound levels inside dwellings from these sources are low, the dwellers evaluate the noise as annoying. The paper presents the results of investigation of annoying low frequency noise in dwellings. Measurement results are shown and methods of annoyance assessment are discussed.

156 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Visual Contrast Thresholds During Single - Axis and Dual - Axis Whole Body Vibrations Authors: Barbara Griefahn, University of Dortmund, ( Germany) Peter Broede, University of Dortmund, ( Germany) Wolfgang Jaschinski, University of Dortmund, ( Germany) Volume 3, page 1255, paper no. 68 Abstract: The hypothesis was proved that whole body vibrations transmitted through the seat impair spatial reti- nal resolution and oculomotor alignment parallel to the vibration axis. More specifically, it was assumed that the decrement increases gradually from single-axis lateral via single-axis vertical and dual-axis linear to dual-axis circular motions. 20 subjects (19-26 yrs, 14 men, 6 women) with good vision participated in the study where in separate experimental sessions either fixation disparity or contrast threshold for vertically and horizontally oriented test patterns were determined during 5 conditions. The latter com- prized a control (az = ay = 0) and 4 conditions where 5 Hz sinusoidal vibrations of 1.2ms-2 r.m.s. were applied separately, either in the vertical or in the lateral direction or simultaneously in both directions, once without and once with a phase shift of 90 thus causing dual-axis linear or circular motions. The variability of vertical fixation disparity and contrast thresholds for horizontal gratings increased significantly whenever the subjects were exposed to vertical motions (alone or combined with lateral motions). These results indicate an increased difficulty to recognize properly characters and graphic patterns that contain horizontal lines. This may lead to the development of asthenopic complaints.

157 Click here to view scanned manuscript ICSV5 Paper Abstract Detection Enhancement Using Colour for Sonar Dis- plays Authors: Ross L. Dawe, Defence Science and Technology Organisation, ( Australia) Edwin R. Galbreath, Defence Science and Technology Organisation, ( Australia) Volume 3, page 1263, paper no. 33 Abstract: This paper describes an investigation of the effect of the inclusion of colour coded signal information in frequency-time-intensity (lofargram) sonar displays on the detection threshold of human observers. An average measured colour gain for human observers gave a systemic improvement in performance which partially negated typical human factors losses associated with making detection decisions from sonar displays. The effect of good and poor contrast between colour hues was also studied for its effect on signal detectability and the quality of bearing information on the display. It was found that the relative brightness of the display cells was the dominating factor in signal detection on lofargrams, rather than the specific choice of colour hues, and that each display must have its choice of colour hues individually tuned for maximum benefit.

158 Click here to view scanned manuscript ICSV5 Paper Abstract The Inﬂuence of Internal Structures on the Sound Ra- diated From a Machinery Hood Authors: L. Oddo, INSA de Lyon, ( France) B. Laulagnet, INSA de Lyon, ( France) Jean-Louis Guyader, INSA de Lyon, ( France) Volume 3, page 1273, paper no. 70 Abstract: A machinery is often composed of a hood radiating sound to the exterior and internal substructures. Ignoring this substructures when calculating the sound radiated by the hood can lead to bad results, when compared to experiment. Howevery taking into account the substructure in a deterministic sense, is generally unrealistic due to their complexity. The aim of this paper is to use the S.E.A. equation in order to derive an equivalent damping due to the internal substructures, and then use it to compute the sound radiated from the hood having an increased damping. This allows us to use the standard computer program of thin structures radiation by, just modifying their damping loss factors. In particular conditions, that will be described, the internal substructures can increase considerably the damping of the hood, and then reduce the radiated sound. The paper present the theoretical derivation of the method, on the case of a cylinder coupled to internal system described by point mobilities. The prediction with exact calculation will be compared to this approach. To show the phenomenon of increasing damping of a master structure coupled to internal vibrating systems, an experiment was made with beam like structures. It will be presented and experimental results compared to theoretical predictions.

159 Click here to view scanned manuscript ICSV5 Paper Abstract Quantifying the Noise Emission of Engine Oilsumps, Valve Covers, etc. Using Artificial Excitation Authors: P.J.G. van der Linden, LMS International, ( Belgium) J. Schnur, Mercedes-Benz, ( Germany) T. Schomburg, Mercedes-Benz, ( Germany) Volume 3, page 1283, paper no. 553 Abstract: Oilsumps, valve covers and distribution covers belong to the main noise radiating parts on modern engines. These parts have in common that their main excitation is a velocity excitation at their fixation to the engine structure. A method was developed to quantify the noise emission of the individual part under artificial excitation. This measurement technique allows the assessment of the parts and their mounting to the engine for efficient variant comparisons. The difficulty lies in the simulation of near to rigid boundary conditions and in the effective velocity excitation. A combination of reciprocal acoustic excitation and inverse force identification is used. The objects are excited by volume velocity sound sources. On the basis of a reciprocity relationship and inverse force identification the effective noise emission is quantified for spatially uncorrelated velocity excitation. A comparison of aluminium, plastic and rubber decoupled oilsumps is shown as an example.

160 Click here to view scanned manuscript ICSV5 Paper Abstract Effect of Tooling Parameters on the Relationship Be- tween the Radiated Noise and Induced Force in Shear Cutting of Sheet Metals Authors: Ahmad Bahrami, Australian Defence Force Academy, ( Australia) Hugh M. Williamson, Australian Defence Force Academy, ( Australia) Joseph C.S. Lai, Australian Defence Force Academy, ( Australia) Volume 3, page 1293, paper no. 492 Abstract: It has been shown theoretically by Evensen [1] that the noise radiated from impact forming operations is related to the time derivative of the force induced in the machine. In this paper, the validity of this theory is explored for a high speed sheet metal shearing process. Noise measurements were made for various shear blade tooling parameters, such as blade profile, blade clearance and speed of cutting, while dynamic cutting forces were measured simultaneously using a pressure transducer. Experiments include the cutting of profiled sheet metal products as well as flat sheets. The profiled specimens used for this investigation were roll formed sheet steel products with an approximately sinusoidal profile produced by BHP Building Products, Australia. For this product, eight different shear blade profiles of varying blade angles and rake were designed and produced. Comparison of experimental results with theory is discussed along with practical applications to the design of high speed sheet metal shearing operations with reduced radiated noise.

161 Click here to view scanned manuscript ICSV5 Paper Abstract Hermetic Compressor Noise Control by Shell Modifica- tions Authors: N J Agrawal, Kirloskar Copeland Limited, ( India) R. Dubey, Kirloskar Copeland Limited, ( India) S.R. Joshi, Kirloskar Copeland Limited, ( India) Volume 3, page 1301, paper no. 382 Abstract: The noise generated by a hermetically sealed reciprocating compressor reaches the outside environment by traveling through compressor shell. The intensity of the noise reaching outside is known to be sensitive to the geometric configuration of compressor shell. As part of a noise reduction program, compressor shell has been modeled on ANSYS Finite Element Analysis (FEA) Software and modal analysis was performed on the same. The results from this analysis were then cross checked with the near field sound intensity analysis of the compressor on dual channel FFT sound analyzer, B&K 2144. It was found that there were compressor shell natural frequencies of vibration in 1000 Hz to 3000 Hz frequency range and these were very close to the high intensity peaks in the sound intensity spectrum of compressor obtained by using dual channel FFT analyzer. Shell shape alternatives were analyzed for their forced response using ANSYS FEA software; shell of modified shape has shown significant improvements in forced response characteristics in the 1000 - 3000 Hz range. A modified shell has been prototyped. An overall noise power reduction of 1.8 dBA has been achieved, without any associated cost penalty.

162 Click here to view scanned manuscript ICSV5 Paper Abstract Control of the Sound Generated by a Rotary Compres- sor Authors: Nelik Dreiman, Tecumseh Product Company, ( U.S.A.) Volume 3, page 1309, paper no. 365 Abstract: The scheme of hermetic rolling piston compressor vibration and sound generation mechanism has been developed to understand complex inter-relationship between suction and discharge gas pulsations, mechanical forces, such as vane reciprocation roller revolution drive forces of the rotor rotation and electromagnetic forces of the electric motor. One of the sound sources within the compressor is the mechanical friction between the crankshaft thrust surface and facing surface of the outboard bearing. The sound radiated by the compressor has been reduced by useof the special designed thrust bearing (USA Pat. 5,554,015 dated Sept. 10, 1996) which has been pressfit (interference fit) within countersunk recess in the rotor. By press fitting the thrust bearing within the counterbore formed in the rotor, rotation of the thrust bearing relative to the rotor is prevented This results in forming a single frictional pair, the lower surface of the thrust bearing against the upper end faceof the compressor main bearing hub, thereby reducing the amount of sliding fiction within the compressor. The polyamide material used to form the thrust bearing is characterized by a very low coefficient of static and kinetic friction. It helps to diminish the resultant friction thereby increasing the efficiency, reducing overall sound radiated by the compressor as during operation, so at the start, and improve reliability of the rotary compressor.

163 Click here to view scanned manuscript ICSV5 Paper Abstract Determination of Limit Admissible A-weighted Noise Emission Values of Machinery and Equipment Authors: Ilja E. Tsukernikov, AO "NIIpolygrafmash", ( Russia) Volume 3, page 1317, paper no. 229 Abstract: The problem of technical standardization of noise emission values of machinery and equipment is considered as a problem of how to determine limit admissible values of sound power levels of machines by satisfactoring of which it is ensured the fulfillment of noise sanitary norms at operators stations when the scheme of machinery disposition in the room is specified. The system of linear algebraic equations for the limit admissible A-weighted sound power values of machines is derived. Some equations for the mean sound absorption coefficient of a room where machines operate are proposed, which can be used when dealing with A-weighted quantities. The comparison of the values calculated is done using the recommendations of ISO 3744 too, and the most suitable equation is found. As an example the limit admissible A-weighted sound power levels of curds production workshop equipment are calculated.

164 Click here to view scanned manuscript ICSV5 Paper Abstract Simulation Tests in the Indicatory Acoustic Assessment of Machines Authors: Zbigniew Engel, University of Mining and Metallurgy, ( Poland) Dariusz Pleban, Central Institute for Labour Protection, ( Poland) Volume 3, page 1325, paper no. 191 Abstract: The authors worked out two indices of the acoustic assessment of machines: a power index and an emission index, as well as indicatory methods of acoustic assessment of machines. The worked out indices are functions of several parameters such as e.g., variants of the operational conditions of the machine, the acoustic properties of the room. The results of the simulation tests, illustrating the eﬀects of variations of diﬀerent parameters on the values of the indices of the acoustic assessment, are presented in the paper.

165 Click here to view scanned manuscript ICSV5 Paper Abstract An Analysis of the Flow and Sound Source of an Annu- lar Type Centrifugal Fan Authors: Wan-Ho Jeon, Korea Advanced Institute of Science and Technology, ( Korea) Duck Joo Lee, Korea Advanced Institute of Science and Technology, ( Korea) Volume 3, page 1333, paper no. 125 Abstract: Centrifugal fans are widely used, so the noise generated by these machines causes one of serious problems. Especially, in vacuum cleaner fan, not only the discrete tones but also broadband noise are dominant. Past researchers have been focused on the generation and reduction of the BPF tones. In order to understand the generation mechanism of tone/broadband noise, a DVM (Discrete Vortex Method) is used to calculates the flow field and the Lowson’s equation is used to predict the acoustic pressure. The broadband noise of a circular casing centrifugal fan is due to the unsteady force fluctuation around the impeller blades related to the vortex shedding.

166 Click here to view scanned manuscript ICSV5 Paper Abstract The Effect of Workpiece Torsional Flexibility on Chat- ter Performance in Cylindrical Grinding Authors: R.D Entwistle, Curtin University of Technology, ( Australia) Brian J. Stone, University of Western Australia, ( Australia) Volume 3, page 1343, paper no. 373 Abstract: Most of the steady state grinding force models for cylindrical grinding show a dependence on the rotational speeds of both the workpiece and the grinding wheel. If, due to the flexibility of the workpiece drive, a torsional oscillation was superimposed on the mean rotational speed of the workpiece, then according to the cutting force models the cutting forces would also vary about their mean. Any variation in the nagnitude and/or phase of the cutting forces must have an influence on the chatter performance of the machine. Mathematical models have predicted that such would be thecase when the natural frequencies of the machine tool structure and the workpiece drive (torsion) are close. An experimental programme was undertaken to test this idea. An artificially flexible workpiece drive was arranged and the chatter of the machine monitored. It was found that the torsional flexibility prevented ’workpiece chatter from arising and, under certain conditions, grinding wheel chatter was suppressed. The paper briefly outlines the hypothesis, describes the experimental arrangement and presents the results showing the beneficial effects. Some practical applications are provided.

167 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration and Idling Noise in Commercial Circular Saws Authors: Victor Poblete Jorge P Arenas Rolando Rios E. Millar Volume 3, page 1351, paper no. 355 Abstract: This article presents the outcomes of a theoretical and experimental research on vibration and idling noise developed in a set of thirteen circular saws commercially available. The logical difficulty associated to the testing of these two generating sources of noise separately led to the experimentation of these two sources simultaneusly. Due to the fact that it was not easy to find out enough commercially circular saws that allowed the covering and testing of a wide range of variables affecting the generation of noise, modifications in workshop in the geometry of some of them were carried out. It was determined that the natural frequencies increased according to the teeth highness for saws with equal diameter and identical thickness. Furthermore, the natural frequency came out directly proportional to the dimensions of the fixing collar. During the rotation it could be noticed that the natural frequency is divided in two resonance frequencies linearly increased with the angular frequency of rotation. It was observed that the sound pressure level generated by these circular saws varied proportional to the peripherical velocity of rotation.

168 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Insulation of Test Benches for Comfort and Fatigue Assessment of Cars Authors: Pietro Croce, University of Pisa, ( Italy) Pietro Orsini, University of Pisa, ( Italy) Walter Salvatore, University of Pisa, ( Italy) Volume 3, page 1359, paper no. 276 Abstract: Vibration control assumes great importance in test bench design, especially when test frequencies vary in a very wide range. The aim of the paper is to illustrate the studies carried out for the design of the insulating foundations of two big test benches to be built in the FIAT Research Center (CRF) in Turin, The benches, that will be located in a suitably modified existing building, are intended to be employed for comfort and fatigue tests on cars of different type and dimensions, Each bench is equipped with four actuators, able to act independently, producing load time histories whose frequency spectra can vary in a very general way between Oand 200 Hz, The two benches, whose individual surface is about 20 m2, differ mainly on the degrees of freedom of each actuator: in the first bench the load direction is vertical, while in the second one the loads can act in any direction, To satisfy the wide set of design constraints a twin insulation system has been foreseen, using both pneumatic suspensions and elastomeric pads, In the paper, the theoretical analysis carried out are illustrated and the results are discussed, justifying the design choices.

169 Click here to view scanned manuscript ICSV5 Paper Abstract Structure Born Vibrations of Spindle and Their Scat- tered Energy Authors: M. Abdul Mazid, University of Technology, Sydney, ( Australia) Nong Zhang, University of Technology, Sydney, ( Australia) M. Alauddin M.J.S. Hashmi, Dublin City University, ( Ireland) Volume 3, page 1367, paper no. 142 Abstract: Machine tool spindle vibrations are the major causes of hampering its nor-mal workability. The spindle block elements themselves are the carriers of vibrations called as structure born. This work comprises the research of these reasons and the assessment of vibration by a novel parameter propo-sed to call as scattered energy of vibration. Bearing is a complicated elastic body in the spindle head. Allowed profile irregularities of outer and inner races of spindle bearing, allowed tole-rances of rolling elements manufacturing, fit gapes in the nests of the separator, eccentricity and ovality of these elements, allowed errors in assembly are Identified as the major reasons of vibrations. An effort has been made to show how vibrations are created due to those deficiencies which are accepted in design and manufacturlng of spindles. The spindle vibration is generally evaluated by its frequencies and ampli-tudes. These parameters can define the vibration level of spindle but do not assess vibration affect of spindle block life duration or changes in crystallic structure of materials. The impact forces emanated from vibra-tion or in other words scattered energy of vibration which is dissipited around are determined in the work based on simple mechanics. The total scattered energy can be used in predicting the working surface destruct-ion, suffered from vibrations.

170 Click here to view scanned manuscript ICSV5 Paper Abstract Noise and Vibration Minimizing in Machines Threated as Multi-Sources System Authors: Zbigniew Dabrowski, Warsaw University of Technology, ( Poland) Volume 3, page 1375, paper no. 30 Abstract: Minimizing of noise atthe operator’s cage of engineering machines with complex structure requires the location and the identification of sources. Solving of this task is connected with serious difficulties, resulting from the fact that various sources are characterized by varied degree of correlation and that sound propagation, by the surrounding environment and by the machines structure (generally being a non-linear system) results in phase shift and in additional loss of correlation. Moreover, in the course of work the movements of working attachments cause essential changes of both the paths of propagation and the external field. In such a situation simple methods of separation fail to achieve their purpose. The work undertakes an attempt to propose a measurement procedure which would allow to account for the influence that individual sources have on the total noise in the operators cab, and thus to indicate which source should be silenced (eliminated) first. The work is a direct continuation of the study on modelling of the acoustical structure of engineering machines that was presented at the WESTPRAC 94 Conference, and is based on the extensive empirical material regarding vibration and noise in hydraulic excavators working in the most severe operating conditions (strip pits, quarries, etc.)

171 Click here to view scanned manuscript ICSV5 Paper Abstract Modeling of Electromagnetic Excitation Forces of an In- duction Motor for Vibration and Noise Analysis Authors: Dae-Hyeon Cho, Samsung Aerospace Industries Ltd., ( Korea) Kwang-Joon Kim, Korea Advanced Institute of Science and Technology, ( Korea) Volume 3, page 1381, paper no. 19 Abstract: Electric motors are the most fundamental source of motion generation mechanisms in both industrial and household products. Noise and vibration problems in such products can be remedied in general at each of the three stages ; source-transmission path-receiver. Some problems, however, caused inherently by the motors can not be successfully resolved by working on the transmission path or the receiver alone. In this regard, importance of the noise and vibration problems in the motor itself has been increasing so far. In this paper, a method is presented, which can calculate electromagnetic forces in quantitative as well as qualitative aspects, based on equivalent transformer circuit. Here the rotor slot skew, permeance ﬂuctuations and rotor dynamics are also taken into consideration. Even though this method does not yield information so detailed as the FEM, the computational burden is very low. By using this method, distributions of the electromagnetic forces in both spatial and temporal frequency domain are investigated and eﬀects of the rotor eccentricity and rotor-slot-opening are also investigated. The reason why the exciting force increases and consequently the noise level goes up in reality with loading is explained. Finally, results of the simulation are compared with the experiments.

172 Click here to view scanned manuscript ICSV5 Paper Abstract Improved method for estimating complex modulus and damping Authors: Sven Gade, Bruel and Kjaer, ( Denmark) Niels Johan Wismer, Bruel and Kjaer, ( Denmark) Volume 3, page 1391, paper no. 55 Abstract: This paper introduces an improved method for estimation af Complex Modulus. The stress-strain relationship of non-resonant visco-elastic materials, generally used in damping treatment of structures, can be described by 2 properties, such as the perfectly elastic (in-phase) stress-strain modulus and the loss factor, The values of these properties need to be determined in tension or compression for material used as unconstrained damping layers and as anti-vibration mountings under foundation blocks. Using a dual channel FFT analyzer, the specimen can be excited using wide band random excitation, and the properties can be determined as a continuous function of frequency. The method can normally be used up to a frequency which is a factor of 2 to 3 below the first resonant frequency for the test-setup. For the proposed improved method the frequency range is extended to well above the first resonant frequency for the test-setup. The method is verified by use of the well known 3dB bandwidth method.

173 Click here to view scanned manuscript ICSV5 Paper Abstract Characteristics of Chiral Slab in the Applications of Wave Absorption Authors: C.C. Sung, National Taiwan University, ( Taiwan) Ro Ruyen Yuh-Ming Chang, National Taiwan University, ( Taiwan) Volume 3, page 1399, paper no. 538 Abstract: Acoustically active materials (chiral materials) that lack centrosymmetry due to chirality in their mi- crostructures can be characterized by the constitutive relations ji = ji + ij + kkij + cji and ji=(+)ji+(-)ij + kkij + cji. Accordingly, two longitudinally, two right circularly and two left circularly polarized elastic waves can propagate in chiral medium. Using appropriate ﬁeld representations along with prescribed boundary conditions, scattering characteristics at chiral interfaces can be realized. In this paper, reﬂec- tion and transmission characteristics of chiral slabs bounded by achiral media for longitudinally elastic waves with normal incident are thoroughly discussed. Results obtained can be applied for the design of broadband acoustic impedance transformer and acoustic absorbers which will be reported in the near future.

174 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustical Properties of Ferrous Metal With One and Two Alloying Elements Authors: Nelik Dreiman, Tecumseh Product Company, ( U.S.A.) Volume 3, page 1407, paper no. 366 Abstract: Wide use of metals for a machine structural component such as drive trains, valve trains and where combination of high strength at both low and elevated temperatures are required, and necessity to reduce noise of the mechanism operating at such extreme conditions made it necessary to study the effect of such common factors as chemical composition, heat treatment, and method of manufacturing on acoustical characteristics of the construction metals. In the analytical and experimental work reported in this paper, sound radiation of the rectangular plates made from iron-chrome (Fe - Cr) and iron-chrome- munganese (Fe-Cr-Mn) alloys have been studied in some details. The analytical study shows that the sound radiation efficiency of a metal depends upon geometry, external static and dynamic loads, boundary conditions, surrounding medium, physical and mechanical properties of the metal. The analysis of the experimental data indicuted that the change of the chemical composition and corresponding alloys structural changes affected the attenuation rate of the sound radiated by the plutes. High rate of the sound attenuation have been recorded for the ferrous alloywith18% Cr and 12% of Mn. The variety of alloying elements added to the iron or steel to modify its physical and mechanical properties as well as heat treatment, and mechanical working of the metals should be investigated for noise reduction potential and nondestructive diagnostics of machinery and materials.

175 Click here to view scanned manuscript ICSV5 Paper Abstract Using Frequency Limited Propagation Data to estimate the Tortuosity of Porous Materials Authors: David E. P. Lawrence, Monash University, ( Australia) Charles G. Don, Monash University, ( Australia) Volume 3, page 1415, paper no. 45 Abstract: The tortuosity or structure factor of a porous medium represents the increase in resistance to normal air flow due to the air following an indirect path relative to the macroscopic acoustic pressure gradient, Along with flow resistivity and porosity, tortuosity is one of the important parameters required in many of the theoretical models used to predict the acoustic properties of porous materials. A commonly used technique for measuring the tortuosity involves saturating the material with an electrically conducting fluid, however, this is inappropriate for unconsolidated granular media such as soils. Alternatively, the tortuosity can be estimated from the high-frequency asymptote of the measured phase speed. In practice, the maximum frequency at which propagation measurements can be made will be experimentally limited. This paper outlines a simple method by which the tortuosity of a medium can be readily estimated, with the aid of a simple theoretical calculation, from experimental data that have not reached the asymptotic value, The method assumes a prior knowledge of the flow resistivity and porosity of the medium. To validate the technique, estimates of the tortuosity of plastic foams and soils are compared with values obtained through a more time consuming curve-fitting approach.

176 Click here to view scanned manuscript ICSV5 Paper Abstract Wave Propagation in Layered Transversely Isotropic Fluid- Saturated Porous Media Authors: Yue Sheng Wang, Northern Jiaotong University, ( China) Zi Mao Zhang, Northern Jiaotong University, ( China) Gui Lan Yu, Northern Jiaotong University, ( China) Volume 3, page 1423, paper no. 412 Abstract: It is well known that the geologic materials are generally porous media saturated with various fluids, and are usually anisotropic due to bedding, compaction and the presence of aligned microcracks. Wave propagation in such porous media is of practical importance in geophysics, hydrology, soil dynamics, earthquake engineering, etc. This paper will examine the propagation of elastic waves through layered transversely isotropic fluid saturated porous media. The analysis is based on the Biots theory. The dissipation due to fluid viscosity is considered. We first derive the characteristic equation of plane waves in an arbitrary layer, of which the closed form solution is presented. This enables us to write the general form of waves in a layer. The results show that three kinds of waves propagate in a layer: the fast and slow quasi-longitudinal waves (QP1 and QP2) and the quasi-transverse wave (QSV). Then, by consideration of continuity conditions at the interface, the transfer matrices between layers are derived. The expressions of amplitudes, phase velocities, attenuation coefficients and directions of the reflected and transmitted waves are presented.

177 Click here to view scanned manuscript ICSV5 Paper Abstract Measurements of Frame Motion In High Intensity Sound Propagation Through Flexible Porous Materials Authors: Konstantin Khirnykh Alan Cummings Volume 3, page 1431, paper no. 266 Abstract: In this paper, a method for measuring the vibrational velocity of the solid skeleton of a flexible, porous, sound-absorbing material is described. This is based on a simple electromagnetic principle, involving a thin conductor that is structurally connected to the frame of the absorbent and placed in a magnetic field. The method appears to yield acceptably accurate data. The sample test results that are presented here demonstrate that useful comparisons can be made between acoustic data and frame velocity measurements, especially where high amplitude, non-linear, effects are present.

178 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Solar Opto-Hydraulic Laser as a New Technology in Vi- bration Engineering Authors: Anatoly T. Sukhodolsky, General Physics Institute, ( Russia) Volume 3, page 1441, paper no. 274 Abstract: The opto-hydraulic laser (actuator) to direct transform the energy of solar radiation into mechanical vibrations is described. The device consists of a chamber with active liquid and optical ﬁber to deliver energy of light inside. As power supplier was used solar concentrator of diameter 300 mm. The vibration generation occurs owing to oscillation a single bubble emerged on the end of ﬁber in liquid. The model of self-organization of heat cycle by nonlinear motion of the bubble is presented to describe main strokes of transformation of radiant energy into energy of mechanical vibrations.

179 Click here to view scanned manuscript ICSV5 Paper Abstract Calibration: Primary, Secondary, and Field Authors: Ernst Schonthal, The Modal Shop (PCB Piezotronics Inc), ( U.S.A.) Volume 3, page 1451, paper no. 547 Abstract: The primary calibration of acoustic and vibration transducers are well standardized and conﬁrmed by round robin inter laboratory test. Secondary calibrartion is also very common with traceability to primary calibration. Examples of a set-up for microphone secondary calibration are discussed regarding accuracy - frequency response testing etc. Field check using reference sources and other methods like Phantom- Calibration is discussed regarding advantages and short comings.

180 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Vibrations in Roller Chain Drives Authors: Thomas Kell, Technical University of Munich, ( Germany) P. Fritz, Technical University of Munich, ( Germany) F. Pfeiffer, Technical University of Munich, ( Germany) Volume 3, page 1459, paper no. 432 Abstract: The aim of the research described in the paper was the evaluation of a complete mechanical model of a roller chain drive and the development of a sophisticated measurement technique to verify the model and to understand the physically processes. The main topic of the paper will be the measurement technique and the verification of the model. Roller chain drives are typically applied in combustion engines. Especially at lower rotational speeds the drive is a major noise source of the engine. The time dependent rotational speed of the crankshaft, the variable torque of the cam-shaft, the polygonal effect due to the discrete nature of a chain and the impact between a chain link and the guide or pulley excite the vibrations of the system and influences the noise and the wear of the drive. To examine these vibrations a test bench has been built. The measuring of the transversal vibrations of a strand was an unsolved problem because of the hot and oily environment and the geometry of a chain link. This could be fixed by improving an eddy-current based measuring system. In addition a method has been evolved to measure the Iongitudinal forces of a chain link. A comparison between the measuring results and the simulation results will be shown.

181 Click here to view scanned manuscript ICSV5 Paper Abstract Unsteady Pressure Measurement: Correction of the Res- onance of the Pneumatic Line Authors: Stephane Gabard, Laboratoire d’Etudes Aerodynamiques, ( France) J. Peube, Laboratoire d’Etudes Aerodynamiques, ( France) Christophe Picard, Laboratoire d’Etudes Aerodynamiques, ( France) Volume 3, page 1467, paper no. 424 Abstract: The reliability of a real time unsteady pressure measurement system is of great interest in many domains of industry and research. Experimental constraints often implies the presence of a pneumatic line between the pressure tap and the transducer, which causes and amplitude and a phase distorsion of the pressure signal to be measured. Corrections of this resonance phenomenon obtained by analogical (active filters) or numerical (inverse transfer function) methods, prevent any simultaneous temporal study of velocity and pressure. A mechanical method of correction consisting in reducing the tube section on a certain length (restrictor) is also generally used, but without any a priori optimization of its geometry. This paper presents a modelization of the transfer function of the pneumatic line: the analytical study displays the respective influences of the different geometrical elements of the pneumatic line. Never- theless, the complexity of the transfer function doesn’t allow the a priori determination of an optimum geometry of the pneumatic line. Our study provides a methodology to optimize the geometry of the restrictor, using a non-dissipative model of the flow in the tube, associated with a quasi-steady flow assumption in the restrictor.

182 Click here to view scanned manuscript ICSV5 Paper Abstract Power Flow Using Electro-Optic Holography, Part 1: Ob- taining the Structural Phase Authors: Gary A. Fleming, NASA Langley Research Center, ( U.S.A.) Jonathan D. Blotter, Idaho State University, ( U.S.A.) Volume 3, page 1475, paper no. 344 Abstract: Electro-Optic Holography (EOH) is a laser based, full field diagnostic technique used to measure micron sized deflections in statically displaced or vibrating structures. When applied to dynamically excited objects, EOH yields the time averaged displacement profile of the object surface. To obtain the structural power flow from EOH measurements, the structural phase must be extracted. This paper provides an overview of the EOH technique and describes a novel method successfully used to obtain the vibrational phase from EOH measurements. Experimental results from a sinusoidally driven cantilever beam are presented in support of this new method.

183 Click here to view scanned manuscript ICSV5 Paper Abstract Real-Time Vibration Mode Imaging Using Photorefrac- tive Holography Authors: Ken L. Telschow, Lockheed Martin Idaho Technologies Inc, ( U.S.A.) V.A. Deason, Lockheed Martin Idaho Technologies Inc, ( U.S.A.) Volume 3, page 1483, paper no. 342 Abstract: Advances in optics over the last two decades have led to the development of optical processing mechanisms in photorefractive materials that provide unique capabilities for intelligent sensing applications. These capabilities include adaptability to environmental effects, image correlation, and optical computing. This paper describes the utilization of photorefractivity for performing noncontacting optical vibration detection that is most useful for small peak amplitudes less than the optical wavelength / 4*pi. Multi-wave mixing with synchronous detection allows measurement of both the vibration amplitude and phase of a vibrating surface directly as a function of the excitation frequency. Narrow bandwidth detection with flat frequency response can be achieved at frequencies above the photorefractive response ( 100 Hz). A minimum detectable displacement amplitude of a few picometers has been demonstrated for a point measurement, with the possibility of further improvement. Full-field imaging of vibrating surfaces is performed in a manner that employs the adaptive properties of the photorefractive effect for real-time processing. The result is an output image intensity directly proportional to the vibration amplitude for small amplitudes, making this approach complimentary to other electronic speckle interferometry methods. An all optical vibration measurement technique is demonstrated by employing laser thermoelastic heating for excitation. Measurements of a vibrating stainless steel plate are presented showing the capabilities of the photorefractive approach for vibrational spectral analysis.

184 Click here to view scanned manuscript ICSV5 Paper Abstract MALICE, the Efficient Acoustic Imaging System for Pre- cise Noise Source Localization Authors: D. Vaucher de la Croix, METRAVIB RDS, ( France) D Webster, Pacific Noise and Vibration, ( Australia) Bernard Garnier, METRAVIB RDS, ( France) F. Molliex, METRAVIB RDS, ( France) Volume 3, page 1491, paper no. 293 Abstract: Aiming at a better understanding of noise measurements processing, the acoustical imaging software package "MALICE" permits a complete mapping of any tested unit. Indeed this analysis tool is connected to the appropriate measurement system and performs specific processing finally delivering a fine representation of the acoustic sources distribution (including a unique focusing capability).

185 Click here to view scanned manuscript ICSV5 Paper Abstract A New Tool for Sound Proofing Inspection: the SALSA System Authors: D. Vaucher de la Croix, METRAVIB RDS, ( France) Bernard Garnier, METRAVIB RDS, ( France) D Webster, Pacific Noise and Vibration, ( Australia) F. Molliex, METRAVIB RDS, ( France) Volume 3, page 1499, paper no. 292 Abstract: Acoustic imaging techniques based on nearfield phased pressure or intensity mapping are now well known and provide a very explicit view of the localization of the predominant noise sources (hot spots)on any kind of surface (machinery casing, car body, engine block, vessel hull, etc.). Nevertheless, the constraint of sampling accurately and regularly the acoustic volume around the investigated object requires a very high order of sophistication; in most of the practical situations, it is not even physically feasible because of the presence of obstacles like pipes, ducts, surrounding equipment, insufficient clearance, for example. Normally, the imaging processing can be made only when a regular grid (generally a large rectangle per side of the object) sampled at perfectly constant intervals has been acquired under experimental conditions. METRAVIB RDS has developed the new SALSA toolbox to overcome this difficulty by introducing a much more flexible approach: I- the measurement is made from an hand-carried small array of microphones looking exactly like a ping-pong bat, - any accessible place is measured and the coordinates of two corners of the bat are memorized as they were for each measurement, - a 2-D or 3-D specific interpolation algorithm is then used to numerically remesh the measurements surface, and "extension" formulae are used to fill at best (i.e. as neutral as possible for the final processing) the eventual blanks. The final imaging process(of which the back propagation formalism is an essential element to neutralize the nearfield interferences and to image the noise sources precisely where they are) is made on the resulting fictive surface. Examples of applications will be provided such as the diagnosis of acoustic leakage of car door sound-proofing and gaskets in real industrial conditions. The application potential is by nature unlimited.

186 Click here to view scanned manuscript ICSV5 Paper Abstract Airborne Acoustic Detection and Localization of Tran- sients Authors: Bernard Garnier, METRAVIB RDS, ( France) F. Molliex, METRAVIB RDS, ( France) D. Vaucher de la Croix, METRAVIB RDS, ( France) D Webster, Pacific Noise and Vibration, ( Australia) Volume 3, page 1505, paper no. 290 Abstract: Using acoustic sensors for detecting, localizing and classifying noise sources of any kind - and in particular related to potentially adverse activities - is an already well established technique and applied in underwater activities. It now appears also as significant multiplier for airborne automatic detection and localizalion of warning sounds such as: blasts, gunshots or shouts in public buildings such as stadiums, big transportation infrastructures, greatand crowded events VIP protection, etc, low altitude aircraft, helicopters, unmanned vehicles, etc. as a temporary or permanent protection of sensitive plants (energy production, telecommunications, military plants, etc.), desert borders, etc, snipers and other terrorist fire-arm actions against police forces, international peace corps, etc. artillery localization and aggressor identification in cease-fire international verification, etc. The peculiarities of low altitude sound propagation in air, the numerous echoes in urban and suburban environments, the high leveI of ambient noise, the variability of atmospheric conditions, make airborne acoustic detection and localization very chal- lenging and specific compared to the Underwater sonar know-how. METRAVIB RDS and its Australian Subsidiary PNV have established an impressive record of experience and applications over the past four years providing to this presentation a real time flavour. The key features of airborne acoustic detection and Iocalization of transient sounds will be presented together wilh their practical technological embedded. Typical performance and intrinsic potential and limits of this technique will also be explored.

187 Click here to view scanned manuscript ICSV5 Paper Abstract Quality controlled separation of outdoor noise component(s) contributed by continously working plants applying online measured Lx-confidence limits Authors: Alois Heiss, Bavarian Ministry of Environmental Protection, ( Germany) Volume 3, page 1511, paper no. 79 Abstract: In case of necessary assessment of already existing noise sources like industrial plants, the separation of the interesting sound component from the residual environmental noise is a well known common task. A method is presented which uses an appropriate noise evaluation index Lx (percentile) for this purpose, for instance L50. As LX index values from measurement, like those of any other kind of evaluation index, have limited accuracy due to the ubiquitous stochastic level fluctuations, this uncertainty should be explicitly taken into account within the assessment procedure. For this reason a software suitable for laptop PC has been developed for real time measurement of the Lx confidence limits. By these datas, transferred into a further appropriate processing software, it is possible to present the final results of the sound separation, their related confidence limits and the resolution limit of the separation method. This new technique of quality control is demonstrated in the version for application to the noise assessment of continuously working plants like power stations etc., a some more sophisticated type of case than that of meresly switching on or off the interesting single sound source. An example of a field measurement and its result is presented.

188 Click here to view scanned manuscript ICSV5 Paper Abstract Bringing Order into the Chaos of Multichannel Systems Using Transducers with Integrated Identification Authors: Jrgen Bðkke, Bruel and Kjaer A/S, ( Denmark) Helge Larsen, Bruel and Kjaer A/S, ( Denmark) Birger Kriegbaum, Bruel and Kjaer A/S, ( Denmark) Bernard Ginn, Bruel and Kjaer A/S, ( Denmark) Volume 3, page 1519, paper no. 64 Abstract: For many years the measurement community has desired transducers with built in (integral) identification to ease the task of installation of instrumentation. This paper describes how a commercially available component has been adapted to fulfil this requirement. For the hardware to be considered as suitable, a certain number of requirements have to be fulfilled by the memory and the interface components employed e.g. ability to operate over two-wire, co-axial cable without disturbing the desired signal. Relative to the transducer itself, the integrated identification hardware must be small and lightweight, be low cost and have low power consumption. There should also be the possibility of two way communication over more than 100 m cable length. The two-wire interface demands are set by the standard coaxial-interface used for accelerometers with built-in constant current line drive (e.g. DeltaTron) amplifiers. Once the requirement for a co-axial interface has been fulfilled, its implementation in other transducers, where separate wires are available, poses no additional problems. Various well known solutions were examined and rejected, mainly because the necessary adjustment required for two-wire operation caused conflicts due to increased complexity, size and price. The suggested hardware solution is based on a Dallas Semi- conductor component which communicates via a unique, two-wire interface called MicroLANTM.One of these components is an E2PROM, and with a little additional hardware this device fulfils requirements of the user. Examples of implementation are given: a single microphone and DeltaTron preamplifier unit in conjunction with a signal conditioning unit used to interrogate the transducer; a multichannel microphone array (over 100 channels) used with an IDA (Intelligent Data Acquisition) system where integrated transducer identification is used to reduced the configuration time considerably.

189 Click here to view scanned manuscript ICSV5 Paper Abstract System Identification of Piezoceramic Beams Authors: Bor Tsuen Wang, National Pingtung University of Science and Technology, ( Taiwan) Rong Liang Chen, National Pingtung University of Science and Technology, ( Taiwan) Volume 3, page 1527, paper no. 541 Abstract: This paper presents the system identification technique by applying PZT actuators and PVDF sensors. An array of finite-length PVDF films is equally spaced and distributed over a cantilever beam acting as sensors. Two finite-length PZT patches are bonded symmetrically and excited 180 degrees out of phase for pure bending excitation. The theoretical base of modal analysis for system identification of piezoceramic beams is presented to derive the frequency response functions (FRFs) in conventional modal format. The physical interpretation of PZT and PVDF mode shape functions are characterized respectively. The FRFs between the PZT actuators and PVDF sensors are experimentally measured. By the operation of a series of FRFs and the application of modal parameter extraction method, the modal parameters, including system natural frequencies, mode shapes and modal damping ratios, can be obtained. Both theoretical and experimental approaches agree very well. The system information can be used for control applications and also be applicable to structural failure diagnosis.

190 Click here to view scanned manuscript ICSV5 Paper Abstract Method for Problem of Khladni Figures Solution Authors: Michael S. Sedov, Nizhny Novgorod Academy of Architecture and Civil Eng., ( Russia) Volume 3, page 1535, paper no. 520 Abstract: A method aIlowing to solve the problem of wave nature of simple and complicate figures of sound oscillations of thin rectangular plates is proposed. The base of the method is presentation of transformation of wave energy. Phase raiding of propagation of free bend waves as a wave motion inside the plate with minimal energy losses has information about the spectra density of own oscillations and about the process of generation of figures at each own frequency. For instance, it was derived that in a plate with the free edges the figures with recliner and curve centers lines are formed with uniform and nonuniform bend waves. Sequence and image of Khladni figures are obtained analytically. In particular it was proved that round or cross center lines which were traditionally considered as simple forms are complicated forms. Experimental investigations confirm this statement.

191 Click here to view scanned manuscript ICSV5 Paper Abstract Support Conditions, Their Effect on Measured Modal Parameters Authors: Thomas G. Carne, Sandia National Laboratories, ( U.S.A.) Clark R. Dohrmann, Sandia National Laboratories, ( U.S.A.) Volume 3, page 1539, paper no. 505 Abstract: During a modal test, the structure must be supported in some manner, in order to test it. If a model of the structure has been developed and is to be reconciled with the test data, then the support conditions must either be included in the model or accounted for. For example, they could be ignored in a simulated free test, if they do not affect the structure significantly. Frequently, a precise determination of the actual support conditions is not performed and there is uncertainly in the conditions, particularly in the damping that these condition attach to the structure. This study examines the effects of support conditions on the measured modal parameters, but more significantly, examines how uncertainties in these support conditions propagate into uncertainties in the both the measured modal frequency and damping.

192 Click here to view scanned manuscript ICSV5 Paper Abstract Theoretical and Experimental Study of a Generalized Pseudo-Forces Method for Source Characterization Authors: M.H.A. Janssens, TNO Institute for Applied Physics TU-Delft, ( The Netherlands) C.M. Langeveld, TNO Institute for Applied Physics TU-Delft, ( The Netherlands) Jan W. Verheij, TNO Institute for Applied Physics TU-Delft, ( The Netherlands) Volume 3, page 1547, paper no. 380 Abstract: The ’pseudo-forces method’ can characterize the strength of compact structure-borne sound sources. It allows for multi-dimensional behaviour of the source, whilst the measurement effort remains limited. In previous work the validity and practicability of the method was confirmed. The indirect nature of this method, however, introduces some (arbitrary) choices in substitution force location and in the transfer matrix analysis. This complicates the comparison of different experiments. In the current work an effort is made to introduce modal information of the free source, which then allows for a unique interpretation of the results and comparison of experiments using different force positions. At the same time the measurement effort needed for the characterization is kept limited. The validity and practicability of this new technique is tested by experiments on a compact source. This expansion of the method broadens the application range of the method and facilitates the translation of the results of a characterization experiment to the low noise design practice.

193 Click here to view scanned manuscript ICSV5 Paper Abstract Experimental Spatial Matrix Identification Method (Pre- sentation Of Current Theory And Fundamental Verifi- cation) Authors: Masaaki Okuma, Tokyo Institute of Technology, ( Japan) Tatsuya Oho, Tokyo Institute of Technology, ( Japan) Volume 3, page 1555, paper no. 320 Abstract: In this paper, the authors present a new experimental spatial matrix identification method that they have been developing. The method is to identify a set of the mass, damping and stiffness matrices that can represent the dynamic characteristics of an objective structure from experimental FRFs. The theory of the method is explained at first. Then, the result of an identification of a basic frame structure, which is made of L-shaped cross-sectional steel components, under the free-free boundary condition is presented. Both bending vibration modes and torsional vibration modes are located in the frequency range of the identification. The dynamic characterisitics of the specimen under a different boundary condition are estimated from the previously identified set of spatial matrices, and compared with experimental results to verify the practical validity and usefulness of the method.

194 Click here to view scanned manuscript ICSV5 Paper Abstract Nonlinear Bending - Torsion Modal Interation Under Parametric Excitation Authors: Raouf A Ibrahim, Wayne State University, ( U.S.A.) M. Hijawi, Wayne State University, ( U.S.A.) Volume 3, page 1563, paper no. 296 Abstract: The purpose of this study is to understand the main differences between deterministic and random response characteristics of a cantilever beam in the neighborhood of combination parametric resonance. The beam orientation with respect to the excitation is made in such a way that the two modes are only coupled through parametric excitation and nonlinear inertia forces. This means that both generalized and normal coordinates are the same. For sinusoidal parametric excitation the response will be determined by using the method of multiple scales, and also measured experimentally, in the neighborhood of the combination parametricresonance ω ω , where is the excitation frequency and ω and = µ ± φ µ ωφ are the bending and torsion first mode natural frequencies, respectively, For the random excitation case the response will be predicted usingΩ Monte Carlo simulationΩ and measurement experimentally. The center frequency of the band limited excitation is adjusted to be close to the sum of the bending and torsion mode frequencies.Under deterministic excitation, the dependence of the response amplitude on the excitation level reveals three distinct regions over which linear behavior, or jump phenomena, or energy transfer can take place. Under random excitation, the system may experience a single response, two possible responses or nonstationary responses depending on the excitation level. The response may also be Gaussian or non-Gaussian depending on the excitation level as well. The power spectra exhibit nonlinear interaction between the torsion and bending modes. Experimentally, it is possible to obtain two different responses for the same excitation level by providing some perturbation to the system.

195 Click here to view scanned manuscript ICSV5 Paper Abstract Updating of Non-Conservative Structure Via Inverse Meth- ods with Parameter Subset Selection Authors: Ladislav Starek Daniel J. Inman, Virginia Polytechnic Institute & State University, ( U.S.A.) Milos Musil Volume 3, page 1571, paper no. 272 Abstract: As technological demands push the performance of mechanical structures and machines, more accurate models are required. A problem of increasing importance in mechanical industries is that of producing analytical models which agree with experimental data. Several incompatibilities exist between analytical models and experimentally obtained data. For instance consider the case of finite element analysis (FEA) modelling compared with experimental modal analysis (EMA) data. This case accounts for the majority of activity in vibration modelling used in industry. In this situation the analytical model is characterised by a large number of degrees of freedom, ad hoc damping mechanism and real eigenvectors. The FEM model produces a mass, damping and stiffness matrix which is numerically solved for modal data consisting of natural frequencies, mode shapes and damping ratios. Common practice in industry is to compare this analytically generated modal data with natural frequencies, mode shapes and damping ratios obtained from EMA, The EMA data is characterised by a small number of natural frequencies, incomplete and complex mode shapes and non proportional damping. It is very common in practice for this experimentally obtained modal data to be in disagreement with the analytically derived modal data. The point of view taken is that the analytical model is in error and must be refined or corrected based on experimental data. The paper will deal with updating procedures: - for complete modal and spectral data - incomplete modal and spectral data with complete mode shapes, incomplete modal and spectral data with incomplete mode shapes. Relations for computing design parameters m, b, k from coefficient matrices M, B, K will be given too. Examples will illustrate the theory.

196 Click here to view scanned manuscript ICSV5 Paper Abstract Mode Studies in Musical Instruments Authors: Uwe J. Hansen, Indiana State University, ( U.S.A.) Volume 3, page 1581, paper no. 367 Abstract: All pitched musical instruments rely on resonances in some form for frequency selection and amplification. In most percussion instruments, string instruments and string keyboard instruments a membrane, the instrument body or a sound board is largely responsible for radiation from the instrument. The normal modes of these structures thus have a significant influence on the sound heard by an audience. Among the techniques used to study such normal modes are near field mapping, holographic interferometry, electronic speckle interferometry, computer animated modal analysis and theoretical finite element methods. These techniques will be discussed and illustrated with examples on Handbells, Guitars, Piano Sound Boards and Caribbean Steel Pans.

197 Click here to view scanned manuscript ICSV5 Paper Abstract The Bell - Where Do We Stand Today? Authors: Hervey Bagot, Bagot Bellfoundries, ( Australia) Volume 3, page 1593, paper no. 441 Abstract: The Western bell has a 1000-year history of development as a musical in-strument. The technical improvements in that time have been a mixture of serendipity and science. An historical overview is given in this presentation, and some current problems and research mentioned. About the year 1000 case bronze bells for use in belltowers began a development from the cylindrical shape borrowed from the East. From then to the present day seven important stages can be seen: (1) movement to a new (flared) shape which would give an identifiable musical note by about year 1200; (2) appreciation of the design laws for bells in a musical scale (without resort to mechanical tuning by 1500; (3) understanding the vibrational complexities of the bells, leading to the possibility of harmonic tuning before 1700; (4) description (without understanding) of the modal content of the bell by 1950; (5) revelation of the physical significance of the vibrational modes by 1980; (6) building on the past to design and modify bells, using the mathematical and computational tools now available - from 1980; (7) improving understanding of correct voicing of bells to good effect – also in our day.

198 Click here to view scanned manuscript ICSV5 Paper Abstract Mode Coupling in Tone Sections of a Tenor Steel Pan Authors: Uwe J. Hansen, Indiana State University, ( U.S.A.) Thomas D Rossing, Northern Illinois University, ( U.S.A.) Volume 3, page 1601, paper no. 368 Abstract: Since the SV IV review report on modal analysis studies in steel pans a relatively complete survey of normal modes of a tenor steel pan has been conducted using electronic speckle interferometry. Like holographic interferometry, this technique relies on the time average of comparisons of quasistationary images in the extremal positions of normal mode motion. Computer image processing techniques enable contrast enhancement and close to real time interference pattern observation. A number of interference patterns associated with particular note section normal modes will be shown to illustrate mode patterns, linear coupling and amplitude dependent nonlinear coupling between note sections.

199 Click here to view scanned manuscript ICSV5 Paper Abstract Binaural Recordings and Their Application in the Sub- jective Assessment of Music Rooms and Concert Halls Authors: Riduan Osman, University of Sydney, ( Australia) Volume 3, page 1609, paper no. 528 Abstract: The application of binaural recordings for the comparisons and assessments of the acoustic quality of music rooms and concert halls are discussed. Correctly made binaural recordings can provide easy and precise subjective comparisons and ranking of the acoustic quality of music rooms and concert halls without enduring the disadvantages of relying on the subjects’ acoustic memory. A review of the types of dummy heads, microphone locations, the resulting binaural recordings that can achieved and equalisation required are carried out. The various methods of binaural recording reproduction, using headphones and loudspeakers, for presentation to the listening subjects are discussed and methods of subjective assessments of binaural recordings made in music rooms and concert hall are recommended.

200 Click here to view scanned manuscript ICSV5 Paper Abstract Use of an Auditory Model to Explain the Mechanism of Pitch Discrimination Authors: Suhashini Shankar, University of Technology, Sydney, ( Australia) Suzanne Hogg, University of Technology, Sydney, ( Australia) Volume 3, page 1617, paper no. 472 Abstract: The number and nature of the mechanisms of pitch discrimination in the human ear is not clearly understood. To deepen our understanding of the mechanism involved in perceiving pitch, we have used the auditory model of Meddis and Hewitt (1991). We optimised the parameters and measured the jnd of the model for sinusoidal stimulus. Comparison of our experimental ﬁndings on the mechanism of pitch discrimination, reported earlier, and the performance of the model indicates the single mechanism operating in discriminating pitch.

201 Click here to view scanned manuscript ICSV5 Paper Abstract The Evolution of Partials in Polyphonic Piano Sounds Authors: Lucile Rossi, University of Corsica, ( France) G. Girolami, University of Corsica, ( France) Volume 3, page 1625, paper no. 410 Abstract: The aim of this paper is to present a study of the evolution of partials in polyphonic piano sounds. The identification of polyphonic sounds usually takes place in the frequency domain and works on a small number of partials, but a common problem in most of the identification methods is octave errors. In this paper, the authors consider the identification of polyphonic piano sound signals, that is, several notes played simultaneously from the same keyboard instrument. The evolution in time and frequency of the partials and the distribution of their energy are interesting to investigate in order to use them to identify the notes. For example, the amplitude of the partials could be used to distinguish the case of overlapping repeated notes. Thus the case of a note (N1) played twO times with a short delay between the notes [N1+short delay+N1] is difficult to separate from the case [N1 long+short delay+N2], when note N2 is played during N1s decay. In order to treat these and similar difficult situations, this paper presents a study of the evolution of the partials of different piano notes, which can be used when deriving general identification methods for polyphonic piano signals.

202 Click here to view scanned manuscript ICSV5 Paper Abstract Damping of Bells using Experimental and Numerical Methods Authors: M.H. van Houten, Eindhoven University of Technology, ( The Netherlands) A.J.G. Schoofs, Eindhoven University of Technology, ( The Netherlands) D.H. van Campen, Eindhoven University of Technology, ( The Netherlands) Volume 3, page 1633, paper no. 230 Abstract: The decay rates of the different partials of a vibrating bell are an important characteristic of the bell’s sound spectrum. These decay rates are caused by material damping of the bell structure and acoustic damping due to the surrounding air. Designing new bells, bell founders would like to know the damping of the different partials before they cast a bell since casting a new bell is expensive and time consuming. However, the damping can only be determined accurately experimentally after a bell is cast. Numerical methods (FEM/BEM) can give an estimation of the damping values. To gain a better understanding of the damping behavior of bells, modal measurements were carried out on four different bells to obtain the eigenfrequencies and the material and acoustic damping values of the partials. The results were compared with the results from fast numerical analyses methods utilizing axisymmetric Fourier elements in circumferential direction for both the structural and acoustic analyses. Some characteristic features of the damping values of bells are obtained and the comparison of experimental and numerical results shows that the damping values for most of the seven lowest partials can be predicted fast within 30% of the measured values.

203 Click here to view scanned manuscript ICSV5 Paper Abstract Tuning Marimbas Using Numerical Optimization Authors: Katherine A. Legge, La Trobe University, ( Australia) J. Petrolito, La Trobe University, ( Australia) Volume 3, page 1641, paper no. 126 Abstract: The transverse modes generated when a uniform beam is struck between its two supports are not harmonic. In order to tune the beam so that at least the lowest of these modes are harmonically reIated, parabolic arches are cut on the underside of the beams. The actual dimensions of the undercut are an empirical design determined by tradition, and relate the subtleties of the sound produced with those favoured by the human ear. The current paper takes a very general approach to the problem. Finite element analysis is used to determine the optimal undercut required to tune the beam. However no assumption is made regarding the shape of the cut beyond ensuring that material is not added and that the structure remains a single beam. An optimisation approach is then used to calculate the profile of the beam to satisfy the prescribed frequencies. The calculated profile depends on the optimisation criterion specified. The paper will present a variety of profiles for which the optimization criteria vary from ease of modelling to ease of construction. The results often do not resemble the traditional cut.

204 Click here to view scanned manuscript ICSV5 Paper Abstract Optimization of Acoustical Shields Authors: Nikolay I. Ivanov, Baltic State Technical University, ( Russia) Alexander V. Omelchenko, Baltic State Technical University, ( Russia) Michael M. Samoylov, Baltic State Technical University, ( Russia) Vladimir N. Uskov, Baltic State Technical University, ( Russia) Natalia V. Zuyzlikova, Baltic State Technical University, ( Russia) Volume 3, page 1651, paper no. 469 Abstract: Excessive noise is still one of the harmful reality of our surrounding and consequently it is still in the focus of investigations for many specialists. Often it is not possible to reduce noise in the source as well as by active way and therefore it becomes necessary to use passive noise control means. This paper is devoted to investigation of acoustical shields which might be used at work places situated as inside buildings as at open places and on machines and to a possibility of optimization of shield parameters. A method for calculation of acoustical shields eﬀectiveness and the procedure of analytical optimization are described in the paper. It is suggested that there are two most important actions should be done in order to reduce noise which are, ﬁrst of all, providing the required noise reduction levels, and, the second, making this with the lowest expenses. It was derived that in that case, cost of a shield will depend on its material and square. The algorithm and software for interactive optimization, in other words, selection of the parameters of a shield providing required noise reduction with minimal cost, is obtained. Examples of numerical simulation are also presented.

205 Click here to view scanned manuscript ICSV5 Paper Abstract Finite Element Analysis of an Industrial Reactive Si- lencer Authors: Ben Cazzolato, University of Adelaide, ( Australia) Carl Q. Howard, University of Adelaide, ( Australia) Colin H. Hansen, The University of Adelaide, ( Australia) Volume 3, page 1659, paper no. 350 Abstract: Classical analytical models used for prediction of the performance of reactive silencers are limited to conditions where the dimensions of the duct and resonators are small compared to the wavelength of the sound. Finite Element Analysis does not suﬀer from such limitations and has therefore been used to analyse the design of a reactive silencer for the exhaust stack of a 980MW power station. To assist in the design process, resonators of various dimensions were analysed using FEA which has led to the derivation of expressions for the resonance frequencies of slot-type rhomboid shaped resonators as a function of the geometry. An important design issue is the inﬂuence that adjacent resonators have on the overall performance of the system. It was found that when resonators of similar resonance frequency are in close proximity, they can interact and lead to a decrease in the overall performance compared to that of a single resonator.

206 Click here to view scanned manuscript ICSV5 Paper Abstract High Frequency Ray Acoustics Models for Duct Silencers Authors: Alan Cummings Volume 3, page 1669, paper no. 27 Abstract: Hybrid modal/ray acoustics models for high frequency multimode sound propagation through finite- length dissipative duct silencers are being investigated and in this paper, the very simplest of these - involving no mean fluid flow, two dimensional sound propagation, a locally reacting duct liner and no area change in the silencer - is described. A mode matching scheme is also outlined. Numerical predictions of silencer attenuation from the hybrid model and the mode matching model are compared to experimental data taken from a two-dimensional silencer apparatus, and favourable agreement is noted.

207 Click here to view scanned manuscript ICSV5 Paper Abstract A New Noise Reduced Construction for Exhaust of Pow- erful Internal Combustion Engines Authors: Pavel V. Vorobjev, Baltic State Technical University, ( Russia) Lyudmila Ph. Drozdova, Baltic State Technical University, ( Russia) Michael M. Samoylov, Baltic State Technical University, ( Russia) Volume 3, page 1677, paper no. 468 Abstract: External acoustical field of a vehicles is characterized by plenty of components which are generated by different sources. These sources are noise of engine and its units, noise of transmission, noise of elements of a vehicle body, noise of intake and exhaust systems, etc. But, as follows from practice, noise of internal combustion engine (ICE) exhaust gases represents the main part of external acoustical field of a vehicle. Exhaust noise reduction is one of the main and the most complicated problems. Traditional solution of this problem is elaboration of effective exhaust noise muffler. Such mufflers, as a rule, should be of 0.5-1.5 m in length to provide desirable effectiveness for each 100 horse power (hp.) of ICE. Moreover traditional exhaust mufflers usually cause 40-80 mm of mercury column (mm m.c. ) of pressure losses. Thus, to reduce noise of exhaust gases in vehicle with more than 500 hp. ICE it is required a muffler of traditional construction which should be not less than 250-300 liters of volume, what brings problems of its placement at a vehicle, taking into account strong requirements to vehicle overall dimensions and weight. Therefore the vehicles which have the restrictions concerning their dimensions and weight often are produced without any muffler. This fact cause high acoustical overloads in the environment and, as a consequence, confine the application of such machines in national economy. Therefore authors pro- pound a new noise reduced construction to be placed at ICE exhaust of such vehicle. Developed noise reduced construction allows to avoid specific disadvantages of traditionally used mufflers mentioned above. Worked out noise reduced construction consists of a set of metal nets of different cross sections, it has small overall dimensions and do not generate additional ICE exhaust pressure losses. This construction was installed at a heavy vehicle with 870 hp. engine with dimensions of exhaust cross section of 1x0.3 m. Tests showed that installation of developed -construction gives ICE exhaust gases pressure loss of not more than 10 mm m.c. while acoustical effectiveness of the construction consists 4-12 dB in the frequency range of 100-8000 Hz.

208 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract The Attenuation of Noise Entering Buildings Using Quar- ter-Wave Resonators: Results from a Full Scale Proto- type Authors: C.D. Field, University of Sydney, ( Australia) F.R Fricke, University of Sydney, ( Australia) Volume 3, page 1683, paper no. 388 Abstract: This paper continues ongoing research into the use of quarter-wave resonators for the attenuation of noise entering buildings. Previous work involving scale model experiments demonstrated the eﬀective- ness of a multi-cavity resonator system, achieving signiﬁcant attenuation in the third octave bands to which the resonators were tuned (Field and Fricke 1995a, 1995b, 1995c, 1996). Results for experiments with a full scale prototype are now presented, demonstrating the feasibility of such a device for the attenuation of noise entering buildings.

209 Click here to view scanned manuscript ICSV5 Paper Abstract The Design Technique for Reducing the Intake Noise of a Vehicle Authors: Jae Eung Oh, Hanyang University, ( Korea) Kwang Hee Han, Hanyang University, ( Korea) Volume 3, page 1691, paper no. 168 Abstract: The intake noise of a vehicle is analyzed and reduced by using the transfer matrix method as well as the FE analysis code, NIT/SYSNOISE. A speaker excitation system is also proposed, which can analyze the acoustic characteristics of the intake system. It is easy to analyze the intake noise in the laboratory environment, and can be used at an early design stage of the intake system development. And this study proposes the improvement to reduce the level of the intake noise. It is to select the optimum position of a resonator and veriﬁed by NIT/SYSNOISE, FE analysis commercial software and testing the prototype and a proposed speaker excitation system.

210 Click here to view scanned manuscript ICSV5 Paper Abstract Characteristic Boundary Conditions and its Application to Resonance Tube Authors: Seung Chul Kwak, LG Electronics Inc, ( Korea) Ho Seon Rew, LG Electronics Inc, ( Korea) Duck Joo Lee, Korea Advanced Institute of Science and Technology, ( Korea) Volume 3, page 1699, paper no. 118 Abstract: To investigate the pressure pulsation in a resonance tube, a computer program based on the unsteady compressible Euler equations has been developed. The convective terms are constructed using a Roe*s approximate Riemann solver and for high accuracy MUSCL is employed. To limit oscillations near shocks , Koren*s diﬀerentiable limiter is adopted and an explicit two-step Runge-Kutta method is used for time integration. Various characteristic boundary conditions suggested by Thompson, Watson-Myers and Hwang are tested and discussed to understand their physical meanings. Through the above tests , appropriate boundary conditions are selected and applied to simulate the pressure pulsation in the resonance tube. The calculation results are compared with the experiment by Merkli and Thomann. The computed amplitude and the period of pressure pulsation are in good agreement with experiment. It is believed that the practical engineering problems in acoustics can be directly simulated using Euler or Navier-Stokes equations with appropriate boundary conditions

211 Click here to view scanned manuscript ICSV5 Paper Abstract Analysis of Extended-tube Three-pass Perforated Ele- ment Muffler by Means of Transfer Matrices Authors: M.L. Munjal, Indian Institute of Science, ( India) Volume 3, page 1707, paper no. 155 Abstract: A majority of the present-day automobile exhaust systems make use of three-pass mufflers that are characterized by low back pressure and good acoustic performance because of interaction of waves in the three pass tubes with those in the annulus. A frequency-domain one-dimensional transfer matrix model is presented here for an extended-tube three-pass perforated element muffler. Transmission loss values computed therefrom have been shown to reduce to those of the flush-tube configuration in the limit. Finally, results of parametric studies are reported in order to help muffler designers in synthesizing an efficient muffler configuration within a given overall length of the chamber.

212 Click here to view scanned manuscript ICSV5 Paper Abstract Non Destructive Evaluation of Polymers: Some New De- velopments Authors: G. Busse, Universitaet Stuttgart, ( Germany) Volume 4, page 1717, paper no. 503 Abstract: Non destructive evaluation (NDE) of metals is well establish since many decades, techniques based on X-ays, ultrasonics, and eddy currents are familiar to all people involved in quality control. Polymers initially intended to be a cheap replacement for metal have found their way into applications where their high specific strength is Important. As many of these applications are safety-relevant, one is highly interested In NDE of polymer materials, However, as the physical properties of these materials differ significantly from metals, it is obvious that some methods can be applied to polymers and not to metals, and vice versa. This paper deals with the potential of new methods and shows which method provides which kind of information, its advantages and drawbacks. Remote detection of delaminations, impact damage, fibre orientations, and curing processes will be highlighted for glass fibre (GFRP) and carbon fibre reinforced polymer materials (CFRP). The methods to be presented include modulated heat transport, microwaves, ultrasonics and vibrometry.

213 Click here to view scanned manuscript ICSV5 Paper Abstract Non-Destructive Estimation of the Position of a Crack in a Concrete Block Authors: Masato Abe, Iwate University, ( Japan) Kenji Sasaki, Iwate University, ( Japan) Volume 4, page 1725, paper no. 312 Abstract: This paper describes a method to estimate, using several sensors, the position of a crack in a concrete block, most of which is buried in the ground. An array of sensors is attached on the surface of the concrete block, and a vibration pulse is forced using a small hammer. Since the forced vibration reflects at the position of a crack, the position will be easily estimated by picking up the reflection wave with an array of sensor using a beamforming technique if only the reflections from the crack can be detected. However, there were many reflections from the boundaries such as side walls and the bottom of the concrete block, and the surface wave, whose magnitude is much greater than that of the necessary reflection wave from the crack. Therefore, conventional beam forming technique does not offer a good result. By the proposed method, not only the effect of the surface wave but also that of the reflection waves from the side walls are decreased, and the necessary reflections (primary and secondary waves) from a crack are extracted. The position of the crack is estimated using the extracted waves by a beamforming technique. We made three concrete blocks with different types of cracks and the positions of the crack were estimated well with the proposed method.

214 Click here to view scanned manuscript ICSV5 Paper Abstract Enhanced Parameter Identification for Damage Detec- tion in Aerospace Structures Using "Twin" Structures Concept Authors: Pavel M. Trivailo, Royal Melbourne Institute of Technology, ( Australia) L.A. Plotnikova, Royal Melbourne Institute of Technology, ( Australia) L.A. Wood, Royal Melbourne Institute of Technology, ( Australia) Volume 4, page 1733, paper no. 270 Abstract: For safety and economic reasons, it is important for many aerospace, maritime, mechanical and civil engineering structures to have reliable and efficient methods enabling damage identification and their health monitoring. The research investigates a promising new approach to damage detection and structural integrity assessment for aerospace, mechanical and civil engineering structures, which, in contrast to the existing techniques, enables the engineer to step outside the oclosed spaceoe of limited data available using current conventional approaches and to develop a detection strategy which provides fresh new data which, in principle, is simple to generate. The new method is based on existing frequency sensitivity techniques, but it is radically enhanced by the inclusion of data from "twin" structures, a novel concept in this context. Numerical investigations of the proposed method have yielded exceptionally encouraging results, and demonstrated the potential advantages of simplicity (hence lower costs), improved reliability and wider applicability when compared with current techniques. The feasibility of the method is demonstrated using a wide range of structural systems as examples: spring-mass systems; 2D and 3D complex truss structures; beam and frame models. Multiple damage sites have been successfully identified and quantified. The method has been shown to perform well. This technology can be especially efficient for large elastic truss and frame space structures.

215 Click here to view scanned manuscript ICSV5 Paper Abstract Ultrasonic Loss Angle Imaging with Speckle Interfer- ometry Authors: A. Salerno, Universitaet Stuttgart, ( Germany) S. Danesi, Universitaet Stuttgart, ( Germany) D. Wu, Universitaet Stuttgart, ( Germany) S. Ritter, Universitaet Stuttgart, ( Germany) G. Busse, Universitaet Stuttgart, ( Germany) Volume 4, page 1741, paper no. 510 Abstract: Early detection of defects is relevant for maintenance of components. This detection can be based on the way how the propagation of electromagnetic or acoustic waves are modified by the defect (indirect methods). From such results one derive the mechanical aspect of the defect. The influence of defects on the mechanical behaviour can be observed more directly by interferometric mean. Electronic speckle pattern interferometry (ESPI) displays the deformation pattern induced under load, e.g. thermal expansion under absorbed illumination. The presence of a defect modifies the overall deformation pattern, so one needs to compare patterns. If one could heat defects selectively, defects would reveal themselves by their Iocalized thermal expansion. Defects are characterized e.g. by stress concentration, lack of adhesion or cracks: all these influences enhance the local mechanical hysteresis. Therefore elastic waves are predominantly attenuated in such areas and mechanical energy is converted into heat with a consequent thermal expansion. To detect these deformations ESPl-measurements were performed after or while being exposed to ultrasonic excitation. Fringes (= levels of equal deformation) are observed around defects in various kind of materials, e.g. wood and carbon fiber reinforced material. This dark field method (which is similar to ultrasonic lockin thermography) should be suited to detect defects in a sensitive way independently of complicated whoie body-deformation.

216 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Cure Monitoring of Thin Adhesive Layers Authors: D. Geisse, Universitaet Stuttgart, ( Germany) K. Nixdorf, Universitaet Stuttgart, ( Germany) G. Busse, Universitaet Stuttgart, ( Germany) Volume 4, page 1747, paper no. 502 Abstract: Anew method is described that allows to monitor the curing process ofthin adhesive laminates in bonded metal joints. The method responds in a sensitive way todifferences in the properties ofthe adhesive polymer. The experimental setup consists of two ultrasonic transducers coupled to a metal bar specimen and supplied bya network analyzer. The resonance spectrum of the joint metal bar is interpreted in terms of additional twin resonance frequencies which arise in the curing process of the adhesive polymer. The curing function of the effective Youngs modulus and the spectral energy is used as a tool to calculate quality values to characterise slight differences between several adhesive polymers. It has been shown, that already the beginning of the curing process (first 20 minutes) provides sufficient information to recognize differences between the adhesive polymers. However, it is not possible to find such sensitive differences in curing at the final state. The capacity of the specimen is simultaneously measured to evaluate differences in the thickness of the glueline which influences the calculation of the effective Youngs modulus and the spectral energy, We find similarities in the elastic and the dielectric properties of the adhesive during the curing.

217 Click here to view scanned manuscript ICSV5 Paper Abstract Remote Vibrometry for Characterisation of Materials and Processes Authors: Ch. Doettinger, Universitaet Stuttgart, ( Germany) J. Stanullo, Universitaet Stuttgart, ( Germany) Leonid M. Lyamshev, General Physics Institute, Russian Academy of Sciences, ( Russia) G. Busse, Universitaet Stuttgart, ( Germany) Volume 4, page 1755, paper no. 501 Abstract: Vibrometry is basically an old technique allowing for defect detection in an empirical way. The use of piezosensors combined with fast data processing have made this technique even more efficient in terms of quantification and of frequency range. However, mechanical excitation of vibration together with are not always applicable: Samples may be wet or sticky, small to attach even a small sensor to them. In any case, piezoelectric detection hot or cold, or just too every attached sensor affects the dynamic behaviour (stiffness, mass, losses) of the inspected sample. The only rigorous solution to this problem is remote generation and remote detection of vibration. We report results of experiments performed with tunable continuous monofrequency excitation which was performed either acoustically (loudspeaker) or opti- cally by an intensity modulated laser beam. In this case the absorption of periodically deposited energy results in periodical thermal expansion which drives the mechanical excitation. Detection was performed with an interferometric laser vibrometer coupled to a Iockin amplifier. The resolution achieved in these measurements was up to 108.This kind of remote mechanical spectroscopy allowed for the characterisation of processes, e.g. drying of paint on polymers and wood, diffusion of humidity into these materials, and sintering of ceramics.

218 Click here to view scanned manuscript ICSV5 Paper Abstract Non-Destructive Testing of Composites Using Long Waves Authors: Suzanne Thwaites, CSIRO National Measurement Laboratory, ( Australia) Norman H. Clark, CSIRO National Measurement Laboratory, ( Australia) Volume 4, page 1761, paper no. 224 Abstract: A new technique for detecting faults in composite panels has been developed. It Is based on measurements of the local phase velocity of flexural waves in the frequency range 2-30 kHz. Since a broadband continuous excitationis used the method includes source configuratlons and software procedures designed to eliminate the effect of the reverberant field. An X-Y scanning version of the instrument has been built employing non-contact methods of excitation and detection and a handheld field version based on a notebook computer has also been constructed. The method has been used on multi-ply carbon fibre panels with various lay-ups to determine elements of the stiffness matrix and lay-up errors. Delarnina- tions and core damage in Nomex honeycomb/carbon fibre skin sandwich panels of varying thicknesses have also been detected via scattering of the flexural waves off the defects, This has been confirmed by calculations involving a simple scattering model.

219 Click here to view scanned manuscript ICSV5 Paper Abstract Various Methods for Nonlinear Noise and Vibration Sig- nal Processing Authors: W S Gan, Acoustical Services Pte Ltd, ( Singapore) Volume 4, page 1771, paper no. 419 Abstract: Nonlinear Vibration Signals are more well-defined and established that nonlinear noise signals which most works are dealing with electronic noise and the unwanted noise in signals. In this paper, we will consider nonlinear industrial and machinery noise. In particular non-Gaussian noise and chaotic signals and nonlinear vibration signals. First we consider chaotic signals. Here two types of fractal functions are used to represent them: the Weierstrass function and the radial basis function. These functions have to be subjected to computation of their fractal dimension. The Hausdorff definition of fractal dimension is used. Next the technique of higher order statistics is used to process nonlinear noise and vibration signals. The bispectrum is used which is a nonlinear generalisation of the spectral approach to linear time-series analysis. Here we review the method of estimation of bispectrum and study possible applications to non-Gaussian signals, such as chaos. We find that the estimated bispectrum could be used to distinguish between nonlinear deterministic stable systems and nonlinear deterministic chaotic systems. We also consider the properties of one nonlinear model, called bilinear model and study their application to nonlinear noise and vibration signals processing.

220 Click here to view scanned manuscript ICSV5 Paper Abstract Non-Linear Response of Acoustically Excited Panels Authors: A.J. Clark, VIPAC Engineers and Scientists Ltd, ( Australia) L.J. Schmid, VIPAC Engineers and Scientists Ltd, ( Australia) David C. Rennison, VIPAC Engineers and Scientists Ltd, ( Australia) Volume 4, page 1779, paper no. 496 Abstract: As part of the introduction of the J version of thc C-130 Hercules Aircraft it was decided to redesign the aluminium centre and outer wing flaps in composite in order to improve their sonic fatigue durability. Inherent in the process was the need to predict the response of the composite flaps to the acoustic environment: the response was found to be highly non-linear due primarily to the combined action of bending and membrane effects. The paper presents the numerical and analytical methods used to predict vibration levels and provides a comparison with measured responses. It is shown that effects can greatly reduce the maximum response and to ignore them results in highly overestimated strain levels with an associated reduction of associated fatigue life.

221 Click here to view scanned manuscript ICSV5 Paper Abstract Resonant Oscillations Governed by the Boussinesq Equa- tion With Damping Authors: Shamil U. Galiyev, University of Auckland, ( New Zealand) Volume 4, page 1785, paper no. 428 Abstract: Nonlinear, dispersive and viscous terms in the Boussinesq type equation, written for displacement u, are considered as second order values. Media ﬁxed at x=0 (u=0) and excited at x =L (u= lcos wt) are studied. Periodical solutions of the Boussinesq equation are sought by the perturbation method. As a ﬁrst approximation u = f(r) f(s), where f(r) and f(s) are right- and left-hand side traveling waves. Far from a resonance u is a smooth standing wave. Nonsmooth traveling waves appear in the solutions within a frequency band around some resonant frequencies. The solutions display on the one hand generation and interaction of kink-, solitary-and cnoidal- type waves and on the other hand weak nonlinear (quadratic) interaction left- and right-hand side traveling waves. The solutions describe well the resonant sloshing of water [ 1], and nonlinear waves in porous [2], bubbly [3,4] and granular [5] media.

222 Click here to view scanned manuscript ICSV5 Paper Abstract Wave Localization in Hydroelastic Systems Authors: A.K. Abramian, Institute for Problems in Mechanical Engineering, ( Russia) Volume 4, page 1797, paper no. 426 Abstract: The aim of this paper is to describe some new physical effects which (as it has been shown in preliminary investigations) could appear in the interaction between elastic solid of a complicated form and flows of fluid. These basic effects can be described as follows: a) a possibility of existence of localized in space time periodical modes (quasimodes) (in linear models); b) a weak delocalization of these modes ( as a result of resonances in non-linear models); c) a possibilityy of existence of coherent chaotic and quasiperiodic interaction of these modes; In connection with c), we developed the theory of control of these coherent structures. By adjusting the elastic system parameters one can control the properties of localized modes and their time behaviour. The existence of localized modes leads to sharp gradients of additional vibration fluid pressure which acts on the elastic solid (construction), In turn, it could lead to the significant radiation of the construction. The other aim is to know where maxima of this pressure are localized, in order to reinforce the construction. A mathematical analysis shows that there are possible effects a,b and c for potentials V(i) of a singular form. We are going to use different methods to resolve problems. First we will find localized modes and quasimodes for linear equation. The second step is an investigation of the dynamics in nonlinear models. It allows to consider the points b,c and it can be done by two ways: by traditional perturbation theory and by methods of infinite-dimensional KAM theory. As for point c, for dissipative, authors developed mathematically rigorous analytic theory for dissipative systems where the existence of coherent chaotic structures consisting of localized modes has been proved and also it has shown that one can control the inertial form (and thus attractor of system). Developed approaches can be applied also to conservative systems. It should solve problem c and create an algorithm control of coherent structures and their time behaviour in systems. We suppose that one can obtain all type of hamiltonian chaos and that one can control the chaos form adjusting the system parameters.

223 Click here to view scanned manuscript ICSV5 Paper Abstract Aeroelastic Response of a Three Degree of Freedom Wing-Aileron System with Structural Non-Linearity Authors: S.A. Safi, University of New South Wales, ( Australia) D.W. Kelly, University of New South Wales, ( Australia) R. Mohajeri, Sydney University, ( Australia) Volume 4, page 1807, paper no. 399 Abstract: This paper investigates the aeroelastic response of a wing-aileron system subject to incompressible flow. A three degree of freedom wing-aileron model is derived and free-play non-linearity is introduced in the aileron control circuit stiffness. The resulting equations of motion for the system are integrated numerically to give the time history of the wing-aileron motion. It is found that the aileron demonstrate a sustained oscillation well below the linear flutter speed. The effects of the amount of free-play on the aeroelastic response of the system is examined. The amplitude of the sustained oscillation is strongly dependent on the amount of free-play in the aileron stiffness and could provide a catastrophic feedback accelerating the wear which leads to free-play.

224 Click here to view scanned manuscript ICSV5 Paper Abstract Nonlinear Radiation of a Piston Vibrating with a High Amplitude Authors: Valery G. Andreev, Moscow State University, ( Russia) N.B. Brandt, Moscow State University, ( Russia) O.V. Rudenko, Moscow State University, ( Russia) Volume 4, page 1815, paper no. 334 Abstract: Nonlinear wave physics deals basically with effects connected with evolution of disturbances of finite amplitude. A slow distortion of time-spatial and spectral characteristics is observed with wave propagation. But nonlinear effects may be already pronounced at small wave distances from a radiator and they can have a significant influence on the process of radiation of itself. In this paper a radiation of a flat piston vibrating with high amplitude is studied theoretically. At a first step a solution for a piston motion driven by external force is determined. It is shown that a piston subjected to the harmonic force of large amplitude can radiate not only the fundamental frequency but high order harmonics as well. A form of particle vibration near a piston face is disturbed. A nonlinear reaction to radiation is arisen also .

225 Click here to view scanned manuscript ICSV5 Paper Abstract Nonstationary Vibrations in a Catenary-Vertical Hoist- ing Cable System Authors: Stefan Kaczmarczyk, University of Natal, ( South Africa) Volume 4, page 1821, paper no. 99 Abstract: Longitudinal and lateral oscillations in a catenary-vertical hoisting cable system are investigated. The main sources of external excitation in the system are taken into consideration, namely a load due to the winding cycle acceleration/deceleration profile, and a periodic excitation due to the coiling mechanism applied at the winder drum surface. Due to the time-varying length of the vertical cable the natural frequencies and mode shapes of the system vary slowly with time. The system is therefore nonstationary, and its response is qualitatively different from the response of the corresponding stationary parameter system. A mathematical model describing the lateral response of the catenary, and the coupled longitudinal response of the vertical rope, is derived. The non-linear partial-differential equations of motion are discretised by writing the deflections in terms of the linear, free-vibration modes. A non-linear set of ordinary-differential equations with slowly varying coefficients results. The dynamic response of a model example is simulated numerically. The simulation predicts strong modal interactions during a passage through the primary and internal resonances of the system.

226 Click here to view scanned manuscript ICSV5 Paper Abstract Linear Modeling of the Dynamics of an Electrodynamic Piston Compressor Authors: Gyu-Sang Choe, LG Electronics Inc., ( Korea) Kwang-Joon Kim, Korea Advanced Institute of Science and Technology, ( Korea) Volume 4, page 1829, paper no. 20 Abstract: The force acting on the reciprocating piston during a compression cycle shows typically non-linear dynamic behavior in electrodynamic piston compressors. In order to increase the efficiency in design, in this paper, the compression cycle is modeled as a linear spring and a hysteretic damper by 4 different methods. Hysteretic damping coefficient is obtained in all of the 4 methods based on the dissipation energy equivalency corresponding to the area of pressure-volume diagram. Regarding the stiffness, the simplest method is to use the slope of two extreme points in the diagram. Another simple method is to derive the stiffness coefficient by applying piecewise equivalency of the potential energy. The other two methods are to apply describing function approach to the compression cycle alone and a single degree of freedom system comprising the reciprocating compressor cycle. Characteristics of the 4 linearized dynamic models are compared with the full nonlinear model, which are obtained by numerical integration for various parameters.

227 Click here to view scanned manuscript ICSV5 Paper Abstract Time-Domain Computation of Acoustics in Confinements Authors: K.Y. Fung, The Hong Kong Polytechnic University, ( Hong Kong) Volume 4, page 1839, paper no. 299 Abstract: Long-time stable time-domain numerical solution of wave propagation in a bounded domain even with one spatial dimension has been a formidable challenge despite the recent advances in algorithmic development and numerical analysis, The key issue is the treatment of end conditions for a finite domain where waves are allowed to rebound from the ends and return indefinitely with cumulative error due to the inconsistencies and mismatches between the inner scheme and the end scheme. The paper delin- eates the importance of formulation in characteristic variables, as opposed to the analytically equivalent primitive variables, demonstrates the cumulative error, and presents a long-time stable implicit scheme for computation of wave propagation with a distribution of wave sources, forced and unforced boundary conditions, including the recently introduced time-domain impedance boundary for bounded domains, Examples of duct and room acoustics, resonance, active noise cancellation and control will be given.

228 Click here to view scanned manuscript ICSV5 Paper Abstract Transient Wave Envelope Elements for Unbounded Prob- lems Authors: R.J. Astley, University of Canterbury, ( New Zealand) Volume 4, page 1847, paper no. 294 Abstract: The application of wave-envelope element numerical scheme to steady and transient unbounded wave problems is described. The formulation is characterised by the use of conjugated weighting functions in the frequency domain. This yields frequency-independent mass, stiffness and damping matrices and leads to a direct formulation inthe time-domain in which a discrete system of ordinary differential equations can be solved to give transient nodal values of acoustical pressure. The transient equations are local in time and can be integrated by standard single or multi-step methods. There are advantages to formulating the proposed elements in spheroidal rather than conventional spherical polar coordinates. Specifically, the size of the conventional finite element mesh which is required in the vicinity of slender or flat radiating objects can be reduced without compromising the completeness of the trial solution in the outer region. A mapped spheroidal formulation is proposed and computed test solutions are presented. An indirect transient solver is also proposed for the solution of the transient discrete equations. This does not require the storage of non-zero or fill terms and reduces by a large factor the matrix storage and overall CPU requirements for large three - dimensional transient problems.

229 Click here to view scanned manuscript ICSV5 Paper Abstract A Linear Method for Local Structural Modification Authors: Tao Li, Victoria University of Technology, ( Australia) Jimin He, Victoria University of Technology, ( Australia) Volume 4, page 1855, paper no. 568 Abstract: Structural modification is a technique to modify dynamic characteristics of a structure by changing its mass, stiffness and damping properties (also known as spatial properties). The most important dynamic characteristics of a structure are its natural frequencies since they dictate the vibration resonances. This paper describes a method for structural modification based on solutions for linear simultaneous equations. The method can be used to determine multiple mass or stiffness modifications of an undamped structural system in order to relocate a resonance or resonances. It analyses the relationship between the spatial property changes and the natural frequency and mode shape changes. The method provides a more generalised solution for mass and stiffness modifications than some earlier analytical work reported in the literature. The main advantage of this method is that it does not rely on a complete eigenvalue solution of the original system to provide exact solution. However, some drawbacks also exist that hinders wide application of this method in structural modification. These drawbacks will be discussed. Examples of implementation of this method will be presented in the paper.

230 Click here to view scanned manuscript ICSV5 Paper Abstract Mathematical and Computer Modelling of Transitional Processes in Transmissions Incorporating High Torque Harmonic Drives Authors: Vladis Kosse, Monash University, ( Australia) Joseph Mathew, Monash University, ( Australia) Volume 4, page 1863, paper no. 556 Abstract: Harmonic drives were invented in the mid-60s and are currently used in transmissions where large speed reduction ratios are required. Over the last decade several models of harmonic drives for heavy machinery have been developed with an output torque ut to 3000 kNm. It is of utmost importance, at the design stage, to obtain reliable data regarding the behaviour of harmonic drives during transition processes and to estimate its parameters (natural frequencies, magniﬁcation factor, torque variation in diﬀerent parts of the drive). This enables the minimisation of stresses, reduction in overall dimensions and weight of the transmission, and increase in reliability. Equations of motion for these transmissions can be derived using the energy method or by considering the dynamic equilibrium of each link. For analysis of transition processes it is important to account for damping, which is normally considered viscous. This approach is suitable for the analysis of transition processes in conventional transmissions. Attempts to employ this method for the analysis of harmonic drives yields confusing results due to the presence of the stationary link. To overcome this discrepancy, the hypothesis of a moving wall was introduced, and equations of motion for power transmissions incorporating harmonic drives were developed. As a numerical example, a transmission for a walking excavator incorporating a harmonic drive was considered. Peculiarities of computer modelling of such transmissions are also discussed in this paper.

231 Click here to view scanned manuscript ICSV5 Paper Abstract Numerical Computation of Exhaust Noise Through Per- forated Diffuser Using Optimized High-Order Compact Schemes Authors: Jae Wook Kim, Korea Advanced Institute of Science and Technology, ( Korea) Duck Joo Lee, Korea Advanced Institute of Science and Technology, ( Korea) Volume 4, page 1871, paper no. 512 Abstract: Exhaust noise from an electrical power plant is generated owing to high pressure inside the boiler when the gas is suddenly exhausted through a safety valve. To reduce the noise, an expansion chamber with a perforated diffuser is used. Noise generation, propagation and radiation from the exhaust gas system are numerically simulated to investigate the noise generation mechanism and to design the efficient perforated diffuser. The high-order compact schemes which were optimized in the wavenumber domain for high-resolution characteristics are used in this numerical simulation. The OHOC schemes are non- dissipative and much less dispersive than the other low-order standard schemes, and well adapted to computational aeroacoustic (CAA) problems. The OHOC schemes are coupled with the artificial dissipation terms and the fourth-order low dissipation and dispersion Runge-Kutta (LDDRK) time-marching method for solving nonlinear unsteady Euler equations accurately. The characteristics-based boundary conditions are implemented as physical boundary conditions for the OHOC schemes. It is shown that the application of these schemes to simulation of the exhaust gas noise reduction system presents time accurate results with partially oscillating supersonic flows near the perforated diffuser and the reduced acoustic pressure fields through the expansion chamber.

232 Click here to view scanned manuscript ICSV5 Paper Abstract A Wave Based Prediction Technique for Vibro-Acoustic Systems With Cylindrical Shell Components Authors: Wim Desmet, Katholieke Universiteit Leuven, ( Belgium) P. Sas, Katholieke Universiteit Leuven, ( Belgium) D. Vandepitte, Katholieke Universiteit Leuven, ( Belgium) Volume 4, page 1879, paper no. 445 Abstract: In a coupled vibro-acoustic analysis, the structural finite element model and acoustic finite or boundary element model must be solved simultaneously. This results in a very large, non-symmetrical coupled model, which requires a computationally expensive solving procedure. To reduce the size of a coupled model, a wave based modelling technique has been developed. Instead of dividing the structural and acoustic domain into small elements and solving the dynamic equations within each element using simple approximating shape functions, the entire structural and acoustic domain are described by wave functions, which are exact solutions of the structural and acoustic homogeneous wave equation. To these wave functions, particular solutions of the inhomogeneous wave equations are added, so that the governing dynamic equations are exactly satisfied. The contributions of the wave functions to the coupled vibro-acoustic response are determined by applying the boundary conditions in a weighted residual formulation. In this paper, the method is applied to the two-dimensional cases of an acoustic cavity, of which the whole boundary surface consists of a force excited cylindrical shell structure, as well as a cavity, of which only a part of the boundary surface consists of a force excited cylindrical shell section.

233 Click here to view scanned manuscript ICSV5 Paper Abstract Simulation of Friction in Oscillating Mechanisms Authors: D.W. Lee, The University of Auckland, ( New Zealand) D.C. Hesterman, The University of Auckland, ( New Zealand) R.W. Jones, The University of Auckland, ( New Zealand) Volume 4, page 1891, paper no. 418 Abstract: Friction is present in all mechanical systems that incorporate sliding contacts, but is often ignored when developing models to study system behaviour. This is largely because of the difficulties that arise in the numerical simulation of friction models, the equations of motion for which are discontinuous and implicit. The problem is exacerbated when considering oscillatory mechanisms, where multiple velocity zero crossings, and thus friction discontinuities, occur. However the inclusion of friction effects in the models of these systems can be very important when the models are used to quantitatively (rather than qualitatively) represent the system; for example, for the design and testing of system controllers, and for system parameter estimation. This paper begins with a brief summary of the types of friction models currently used and their relative advantages and disadvantages. The difficulties of solving the models using numerical simulation are also discussed. A new method is then introduced, using the example of a simple oscillating mechanism, which has the potential to reduce computing time and to avoid certain other problems encountered with friction simulation.

234 Click here to view scanned manuscript ICSV5 Paper Abstract An Efficient Numerical Procedure for Approximating Acoustic Diffuse Fields Authors: Jean-Pierre Coyette, LMS Numerical Technologies, ( Belgium) Christophe Lecomte, LMS Numerical Technologies, ( Belgium) Karl Meerbergen, LMS Numerical Technologies, ( Belgium) Volume 4, page 1899, paper no. 301 Abstract: Vibro-acoustic testing procedures frequently involve the consideration of a diffuse acoustic excitation (as obtained for instance in a reverberant chamber). Such an excitation can be modeled as a stationary random process. The related spatial correlation functions for pressure and pressure gradients are examined. Handling of such a random acoustic excitation in a coupled (elasto-acoustic) context is studied. An efficient decomposition procedure is proposed in order to recast strongly correlated acoustic excitations into a set of a uncorrelated pseudo-load cases. Numerical applications are presented in order to demonstrate the efficiency of the proposed method.

235 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Dynamical Behaviour of Variators with a Half Ball as a Non-Holonomic System Authors: Miodrag Zlokolica, University of Novi Sad, ( Yugoslavia) Volume 4, page 1907, paper no. 256 Abstract: Diﬀerent kinds of mechanical variators are used as a part of complex machine system. Variators, as transmission system , with a changeable transmission ration, are involved in a lot of complex machines. They are used for changing speed in agricultural machines, industries of cable, carpet and paper industries, mining machines, account machines, etc. Seeing this large use of mechanical variators in industry, the aim of this paper is to describe a dynamical behavior of the general example of the variators of speed as non-holonomic system. In this paper a frontal variator of speed with two discs, half ball and regulator will be analyzed. The non-holonomic connection is in points of physical contact between the discs and half ball. To this system is added mechanical regulator for regulation of variable transmission relation between input and output elements. A damper is added for stabilizing movement. Diﬀerential equations of moving will be solved by using Appell’s equations and by resolving the numerical method. In this way, we are getting an answer to a dynamical and kinematical behavior of mechanical systems under the give us the answer to a working stability a system being observed. Keywords: dynamic, kinematic, non-holonomic system, variator

236 Click here to view scanned manuscript ICSV5 Paper Abstract Frequency Analysis of Composite Beams using a Higher- Order Beam Element Authors: Guangyu Shi, National University of Singapore, ( Singapore) K.Y. Lam, National University of Singapore, ( Singapore) T.E. Tay, National University of Singapore, ( Singapore) Volume 4, page 1915, paper no. 213 Abstract: The objectives of this paper are two fold, one is to present a simple and accurate third-order composite beam element, and the other is to use this new element for the frequency analysis of composite beams. In the analysis of composite beams and plates, a higher-order shear deformation theory can lead to finite elements having the same number of nodal variables but giving solutions with different accuracy. By studying the interpolation order of the element bending strain, this paper presents a simple but accurate third-order composite beam element, which possesses a linear bending strain as opposed to the constant bending strain in existing higher-order composite beam elements. The variational consistent mass matrices are derived from Hamiltons Principle. The present new element is used to solve some frequency analysis of composite beams. The numerical examples show that the transverse shear strains play a very important role in the dynamic behaviour of composite beams. The numerical examples also illustrate that the present composite beam element is more accurate than the higher-order beam elements which are based on the same higher-order theory and having the same number of nodal variables but using a different bending strain expression.

237 Click here to view scanned manuscript ICSV5 Paper Abstract Vibratory Conveyance of Granular Materials Authors: Masato Saeki, Niigata Institute of Technology, ( Japan) E. Takano, Niigata University, ( Japan) Volume 4, page 1923, paper no. 140 Abstract: The flow of granular materials on vibratory conveyors- was studied analytically. Vibratory conveyors have proved useful for widely differing duties from feeding small and delicate components on automatic assembly lines to the transportation of large quantities of raw materials. There is a considerable descriptive data of vibratory conveyors, but for simplicity of analysis much previous theoretical analysis only predicts the motion of a particIe on a vibrating plate. For optimum operating conditions, the behavior of granular materials during vibration must be known. In the present work the distinct element method proposed by Cundall was adapted for a dynamic analysis of vibratory conveyance of granular materials. Granular materials are first assumed as ellipse models by considering shape anisotropy. Then the contact forces are modeled by mechanical units such as springs, dashpots and fiction sliders. It is shown that the mean velocity of transport of granular materials depends on the frequency and amplitude of the vibratory input as well as various physical parameters. The flow patterns obtained by this method appear realistic.,

238 Click here to view scanned manuscript ICSV5 Paper Abstract An Elliptic Perturbation Method for Certain Strongly Non-linear Rotors Authors: Livija Cveticanin, Faculty of Technical Sciences, Trg D. Obradovica, ( Yugoslavia) Volume 4, page 1931, paper no. 28 Abstract: An elliptic perturbation method is developed for calculating solutions of strongly nonlinear systems of theformz+cz+cz=ef(z,z,cc), where z is the complex deﬂection function. The Jacobian elliptic functions are employed instead of the usual circular functions. The suggested procedure can give also a second approximate solution. The method is applied for the equation which describes cyclic motion. The analytically obtained results are compared with numerical ones. They show a good agreement.

239 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Some Principle Points of Noise Legislation in Slovenia Authors: Ferdinand Dezelak, Institute of Occupational Safety of the Republic of Slovenia, ( Slovenia) Volume 4, page 1941, paper no. 44 Abstract: For the last two years Slovenia has been intensively working on new noise legislation. Two acts on community noise have already been introduced and a new occupational noise legislation is now in preparation, in which the author is taking an active part. The prefered noise descriptors in both legislations are the rating levels. In this way both the impulsive and spectral characteristics of noise are taken into account. Noise limits are set for diﬀerent regions, depending on the activities to be protected, the time of day when the noise occurs and the type of noise source. In the ﬁeld of occupational noise the old legislation of 1971 is still used. The new proposed noise occupational legislation is mainly based on EEC 86/188 directives. However, some additional limitations are introduced, which are presented in this article in more details.

240 Click here to view scanned manuscript ICSV5 Paper Abstract Interest of Predictive Simulation for Noise Level Assess- ment at the Work Place Authors: Claude Michel, Caisse Regionale d’Assurance Maladie, ( France) Michel Delfosse, Caisse Regionale d’Assurance Maladie, ( France) Volume 4, page 1951, paper no. 421 Abstract: Designers of industrial buildings do not always know which activity they are dedicated to. Very often, they know neither the machine types nor their acoustic features. This misreading can lead to work situations where employees are exposed to high noise levels (over 85 dBa) due to amplification effect of the building. Noise abatements can be obtained by acoustic corrections which are then more difficult to implement and can be expensive. Even when the above-mentioned parameters are known, they are not often used by designers for noise level assessment but rather for indoor circulation facility and fire damage prevention. Noise level in an industrial room depends on a large number of parameters: - The room geometry (flat room, elongated, L-shaped ...) - The wall absorption properties (absorbent, reverberant) - The fittings (machines, storage, furniture ...) - The sources of noise (machines, fans, vehicles...) It is interesting to be able to predict noise levels in a given industrial room in order to adapt the acoustic treatment in conjunction with a better fitting distribution. A numerical simulation software "RAYSCAD+" designed by National Insitute for Research and Safety in occupational health has been developped in order to give a computer-based tool to people in charge of prevention of occupational risks. This paper is intended to presents some results of numerical simulations from actual situations in different industrial activities and to point out the advantages of such a method to reduce exposures to noise and hearing damage.

241 Click here to view scanned manuscript ICSV5 Paper Abstract Noise at Work - Principles of Risk Assessment Authors: Danuta Augustynska, Central Institut for Labour Protection, ( Poland) Dariusz Pleban, Central Institute for Labour Protection, ( Poland) Dariusz Puto, Central Institute for Labour Protection, ( Poland) Volume 4, page 1959, paper no. 322 Abstract: This paper presents the process of risk assessment resulting from exposure to noise. The process involves: (a) identiﬁcation of noise hazards (noise exposure), (b) risk estimation by determining the likelihood of the occurrence of negative consequences of noise exposure (auditory and non-auditory eﬀects of noise) and the degree of their severity, (c) risk reduction. Admissible values of noise determine the highest acceptable risk level.

242 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract The Diﬃculties Associated with Determining Industrial Hearing Loss Authors: David Eager, University of Technology, Sydney, ( Australia) Volume 4, page 1967, paper no. 48 Abstract: This paper reviews some of the diﬃculties associated with determining industrial hearing loss. The recently introduced legislation in the State of NSW, Australia now makes it illegal for employers to expose their employees to a noise levels that exceeds an 8-hour noise level equivalent of 85 dB(A) or a peak noise level more than 140 dB(lin). How will the Courts now handle employees that were exposed prior to this Legislation? When should employers have taken reasonable precautions to protect their employees from excessive exposure? How and to what extent should these precautions have been taken? Was there a phasing in period and if so what was it? This paper discusses these and other questions associated with the determination of industrial hearing loss.

243 Click here to view scanned manuscript ICSV5 Paper Abstract Direct and Inverse Scattering of Penetrable and Non- penetrable Obstacles by Shape Deformation Authors: D.N. Ghosh Roy, SFA Inc., ( U.S.A.) Luise S. Couchman, Naval Research Laboratory, ( U.S.A.) Jeremy Warner, SFA Inc., ( U.S.A.) Volume 4, page 1977, paper no. 529 Abstract: The results of direct and inverse scattering of plane acoustic waves from impenetrable and penetrable objects are reported here. It is assumed that the scatterer boundary is a superposition of an arbitrary deformation on an underlying simple geometry. The direct problem is solved via the Pade extrapolation of the boundary variations. This results in solving only certain algebraic recursion relations and requires neither Green’s function nor integral representations. The inverse problem of recovering the obstacle’s shape and material parameters from the far-field scattering data is solved by Gauss-Newton minimization. The calculation of the scattered field and its Jacobian involves no more than solving a series of Helmholtz scattering problems in the same domain, namely, exterior to the simple shape instead of the iteratively updated deformed surfaces leading thereby to substantial computational simplifications. Finally, several two-dimensional obstacles of various shapes are inverted for their boundaries as well as their material parameters of mass density and wavenumber.

244 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Wave Scattering From an Air Filled Shell in a Layer of Liquid Authors: Alex Zinoviev, The University of Adelaide, ( Australia) Volume 4, page 1985, paper no. 435 Abstract: A new numerical modelling method for sound wave scattering by elastic objects in an acoustic waveguide is proposed. The method is applied to the case of sound propagation and scattering in a plane 2-dimensional layer of liquid 80 metres deep containing a cylindrical air filled shell of finite wall thickness and an outer shell radius of 8 metres. The incident wave is considered to be the lowest order propagating mode of the waveguide. The reflection coefficient is calculated in the frequency range between 5 and 300 Hz for several values of wall thickness and distance between the shell and the waveguide bottom. Pictorial output shows that the amount of acoustic energy reflected strongly depends upon all variables. Maxima and minima in the reflection coefficient associated with cut-on frequencies of the waveguide modes and structural resonances of the shell are identified. The calculations show that the conventional definition of target strength is inappropriate.

245 Click here to view scanned manuscript ICSV5 Paper Abstract Diffraction of Bending-Gravitation Waves on Crack in Ice Field Authors: Dmitri Azalinov, Institute for Problems in Mechanical Engineering, ( Russia) Volume 4, page 1995, paper no. 427 Abstract: We consider the following problem: There is a reservoir with a constant depth, covered by ice field. The depth is small in comparison with a wave length, The water is considered as an ideal liquid. The ice field is considered as a thin isotropic plate of a constant thickness. There are 2 half-infinite ice plates on the water. From the right to the left runs a plane traveling wave. As a result one obtained: 1) Dependence of transmission and reflection coefficients of the patch width of open water in ice, water depth and ice thickness, wave frequency; 2) Dispersion curves of wave velocities in different mediums (ice, water and ice on the water); 3) Energy flows through the reservoir profile, ice profile and profile of the system ice- water. The reflection and transmission coefficients depend periodically of the patch width; the distance between maximal values of reflection is equal to half-length of the gravitation wave on the water surface.

246 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Reflection From Vibrating Surface Authors: Noboru Watanabe, Waseda University, ( Japan) Yoshio Yamasaki, Waseda University, ( Japan) Volume 4, page 2003, paper no. 369 Abstract: It is taken for granted that the walls of a room are rigid and stable when we evaluate the acoustic quality. But in real conditions, walls which are excited by low-frequency sound are sometimes vibrating and the high-frequency reflection sound from them is phase modulated; i.e. when the wall is moving inward, the pitch of the reflection sound will rise and vice versa. This modulation is a nonlinear phenomenon known as cross modulation. In highly reverberant space, there are many reflections which are reflected by the variable part of the room several times, and the amount of modulation is thought to be greater than single reflection sound. This distortion has been thought to be hazardous to the acoustic quality of an auditorium. The authors have examined the mathematical basics of this phenomenon and made a computer simulation program. The authors show that the amount of the modulation (i.e., the distortion ratio) is greater in small and highly reverberant space than in large and non-reverberant space.

247 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic and Elastic Wave Scattering from a Rigid or Soft Cylinder Authors: Huinam Rhee, Korea Power Engineering Company, ( Korea) Youngjin Park, Korea Advanced Institute of Science and Technology, ( Korea) Volume 4, page 2011, paper no. 202 Abstract: Elastic wave scattering from an acoustically rigid or soft cylinder is studied and compared with the acoustic wave scattering. The behavior of phases as well as magnitudes of partial waves and their total summation of scattered waves are numerically analyzed and discussed. The different phenomena between the acoustic and elastic wave scatterings are discussed. The effect of mode conversion, which occurs between longitudinal and transversal waves, on the magnitudes and phases of partial waves in elastic wave scattering is identified. Some parametric calculations are performed to study different behaviors of monopole and dipole modes between the acoustic and elastic wave scattering. Also, in this paper, summed partial waves for the elastic wave scattering are discussed and compared with those for the acoustic wave scattering, with two different scattering angles.

248 Click here to view scanned manuscript ICSV5 Paper Abstract Shock Propagation in the Presence of Time-Dependent Perturbations Authors: D.G. Crighton Volume 4, page 2021, paper no. 565 Abstract: This talk will report work, part of a joint investigation with G. I. Barenblatt, on shock wave propagation when small-amplitude time-dependent fluctuations are created behind the shock. The analysis is carried out in the framework of Burgers’ equation, and we seek a self-consistent theory in a two-parameter plane (perturbation amplitude, Reynolds number) showing how the perturbations are convected towards the shock, and how they significantly distort the shock profile while being absorbed by the shock. A closed equation is found, within a self-consistent framework, for the mean shock profile, and this is solved by singular perturbation techniques to show that in certain regions of parameter space it is possible for small perturbations to cause a great broadening of the shock width, and a splitting of the shock itself into three regions. Two of these are conventional Taylor shocks, in which convection and thermoviscous diffusion balance; and in the region between them there is a much less rapid transition, deep within the shock, controlled by the fluctuations themselves.

249 Click here to view scanned manuscript ICSV5 Paper Abstract Weak Shock Reflection Authors: John K. Hunter, University of California at Davis, ( U.S.A.) Moysey Brio, University of Arizona, ( U.S.A.) Volume 4, page 2023, paper no. 563 Abstract: The two-dimensional Burgers equation, or unsteady transonic small disturbance equation, is the simplest model equation that describes shock wave propagation in several space dimensions. It provides a quantitative, asymptotic description of the reflection, diffraction, and focusing of weak shock waves in gas dynamics and other physical applications. We will present a number of numerical solutions of the two-dimensional Burgers equation which illustrate these phenomena. In particular, high resolution numerical solutions of the equation for irregular weak shock reflection provide evidence of a small supersonic bubble behind the triple point. Based on these numerical results, we will present a theoretically consistent structure of irregular weak shock wave reflection in which there is a centered expansion fan at the triple point and in which a nonuniform supersonic wave behind the triple point is generated by the reflection of incoming characteristics off an embedded sonic line.

250 Click here to view scanned manuscript ICSV5 Paper Abstract Hysteresis Phenomena in Shock Wave Reflections in Steady Flows Authors: Gabi Ben-Dor, Ben-Gurion University of the Negev, ( Israel) Volume 4, page 2031, paper no. 561 Abstract: The state-of-the-art regarding the hysteresis phenomenon in the regular-to-Mach reflection transition in steady flows as it has been established in the past decade is summarized.

251 Click here to view scanned manuscript ICSV5 Paper Abstract The Propagation of Weaks Shocks in Non-Uniform Flows Authors: N. Kevlahan, LMD-CNRS, ( France) Volume 4, page 2039, paper no. 544 Abstract: A new theory of the propagation of weak shocks into non-uniform, two-dimensional flows is introduced. The theory is based on a description of shock propagation in terms of a manifold equation together with compatibility conditions for shock strength and its normal derivatives behind the shock. This approach was developed by Ravindran and Prasad (1993) for shocks of arbitrary strength propagating into a medium at rest and is extended here to non-uniform media and restricted to moderately weak shocks. The theory is tested against known analytical solutions for cylindrical and plane shocks, and against a full direct numerical simulation (DNS) of a shock propagating into a sinusoidal shear flow. The test against DNS shows that the present theory accurately predicts the evolution of a moderately weak shock front, including the formation of shock-shocks due to shock focusing. The theory is then applied to the focusing of an initially parabolic shock, and to the propagation of an initially straight shock into a variety of simple flows (sinusoidal shear, vortex array, point-vortex array) exhibiting some fundamental properties of turbulent flows. A number of relations are deduced for the variation of shock quantities with initial shock strength MS0 and the Mach number of the flow ahead of the shock MU (e.g. separation of shock-shocks and maximum shock strength at a focus). It is found that shock-shocks are likely to form in turbulent flows with M /M1 > 0.14 0.25, where M is the average Mach number of the turbu- t N − t lence and M1N is the Mach number of the shock in a flow at rest. The shock moves up to 1.5% faster in a two-dimensional vortex array than in uniform flow.

252 Click here to view scanned manuscript ICSV5 Paper Abstract Application of Harmonic Wavelets to Time-Frequency Mapping Authors: David E. Newland Volume 4, page 2043, paper no. 260 Abstract: Harmonic wavelets have simple formulations in the frequency domain and they have proved a good basis for the time-frequency mapping of transient signals. Moreover their computational algorithm allows bandwidth to be chosen arbitrarily so that they offer a variable Q transform, where Q is the ratio of centre frequency to bandwidth. In contrast, the short-time Fourier transform and the Wigner-Ville frequency decomposition method are constant bandwidth transforms, so that Q increases as frequency rises. Although properties of wavelet orthogonality may be used to permit easy retrieval of the input signal, to achieve a high-definition time-frequency map more data is required than that obtained from a single decomposition of the input signal. This is achieved by repeating the frequency decomposition for different, overlapping bandwidths in order to increase the number of points that can be plotted. Because bandwidth can be chosen arbitrarily, a frequency zoom feature can be incorporated into the harmonic wavelet transform algorithm. Also, because harmonic wavelets are complex, with real and imaginary parts, phase variations can be studied. Local changes in the spectral composition of a signal can be recognised, using either wavelet amplitude or phase as the discriminator. Examples of frequency zoom and of segmentation by amplitude and phase are given below. They demonstrate that the complex harmonic wavelet transform offers a computationally-efficient method of signal decomposition. Its principal advantage over the STFT is its variable Q property which becomes important when large amounts of data have to be processed.

253 Click here to view scanned manuscript ICSV5 Paper Abstract Stochastic Signal Information Processing for Acoustic Environment — Use of Wide Sense Digital Filter Authors: Mitsuo Ohta, Kinki University, ( Japan) Akira Ikuta, Hiroshima Women’s University, ( Japan) Volume 4, page 2055, paper no. 88 Abstract: The acoustic phenomenon in the actual living sound environmental system involves a variety of compound problems- Not only the natural, social but also the psychological factors make them further complicated and diversified. The frequency range of fluctuating sound pressure with no D.C. component is so wide that it originally can have a variety of fluctuation patterns with non-stationary and non-Gaussian properties. This presentation gives a basic and essential idea of our works on the stochastic signal information processing for acoustic environment, that is based not only on the lower order linear correlation but also on various types of the higher order nonlinear correlations. The importance of employing these higher order nonlinear correlations is discussed through the concrete establishment of wide sense digital filters. These digital filters are fundamentally based on the hierarchical expansion expression of Bayes theorem by using the orthogonal polynomials. The proposed digital filters can estimate any kinds of statistics of arbitrary functional type of a state variable including the lower order statistics connected with the material-side countermeasures (from a bottom-up way viewpoint) and the higher order statistics connected with the human-side evaluation indices (from a top-down way viewpoint). The validity amd the effectiveness of these filters are experimentally confirmed by applying them to the real acoustic environmental problems.

254 Click here to view scanned manuscript ICSV5 Paper Abstract Analyzing Time-varying and Transient Vibration Prop- erties in Technological Systems Authors: Alexandros Soumelidis, Hungarian Academy of Science, ( Hungary) Jozsef Bokor, Hungarian Academy of Science, ( Hungary) Istvan Nagy, Hungarian Academy of Science, ( Hungary) Volume 4, page 2071, paper no. 507 Abstract: Nowadays the joint time-frequency analysis and wavelet techniques have stepped out from the academic research sites and spread out to several industrial applications. The static nature of the conventional spectral techniques used in the analysis of vibrating structures means considerable limitation in certain type of systems and problems arisen on them. Fast changes in the vibrating structures and the presence of transient effects need advanced methods for a compromise-free analysis. The startup or shutdown processes of large rotational machines are typical examples. Continuous monitoring and failure detection of the startup process of large rotating machines (e.g. turbine - turbo generator machine group in conventional or nuclear power plants) is a significant means to avoid serious damages or accidents, hence to save costs of operation and maintenance. The application of wavelets (1) in analyzing the transient vibration process by preserving the harmonic behavior of vibrations in the joint time-frequency methods, e.g. the short-time Fourier transform, the Gabor transform, the Wigner-Ville transform, and their generalizations and completions (2). A new, novel approach with wavelets stems from the approximation properties of these type constructs. The approximations of functions (i.e. signals) belonging L2, Linf, H2, Hinf, as well as the unit disc form nowadays a rapidly evolving field with applications in the identification and detection (3,4). This paper is devoted to investigation how can a priori information (derived from the physical and technological knowledge) be used in wavelet approximations with the purpose of efficient detection specific phenomena in the vibration signals. The appropriate selection of the mother wavelet is crucial in this action, which - sorry to say - cannot be done with full freedom; a significant argument is computability , i.e. the existence of realizable algorithm. The example used to represent methods is based upon real records of startup processes on turbo-generator machine groups of the Nuclear Power Plant Paks (Hungary).

255 Click here to view scanned manuscript ICSV5 Paper Abstract Speech Signal Enhancement Based on a Sinusoidal Model Authors: Michiko Kazama, Acoustic Consultant, ( Japan) Takahiro Ohnishi, Kogakuin University, ( Japan) Mikio Tohyama, Kogakuin University, ( Japan) Volume 4, page 2079, paper no. 374 Abstract: This article describes a method for reducing the noise of noisy speech signals based on a sinusoidal wave model (T. Quatieri, and R. Mcaulay IEEE ASSP-34,(6) 1986 pp1449-1464). The authors reconﬁrm that intelligible speech signals can be synthesized, even using only a few (say 5) sinusoidal waves, and propose a spectrum peak-picking method for noise reduction. The sinusoidal components necessary for speech signal representation are extracted from noisy speech using the short-time Fourier transform (STFT) and the noise-reduced speech signals are synthesized. This method increases the signal to noise ratio (S/N) of recovered speech signals, but the tonal quality is not completely acceptable. The authors also investigate the estimation of speech signals under noisy conditions using a harmonic sinusoidal model. They propose using a multi-windowed STFT (MW- STFT) to estimate the fundamental frequency of a speech and its harmonics sieving. Speech quality and S/N enhancement using MW-STFT based on the harmonic sinusoidal model are also demonstrated.

256 Click here to view scanned manuscript ICSV5 Paper Abstract Mutual Correlation Characteristics Between Sound Level and Electric Field Intensity Fluctuation in Connection With Electromagnetic Environmental Problem of VDT Games Authors: Hitoshi Ogawa, Hiroshima National College of Maritime Technology, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2087, paper no. 329 Abstract: In this paper, some generalized regression analysis method considering not only linear correlation but also higher order nonlinear correlation information is especially proposed in order to find mutual relationship minutely between sound and electromagnetic waves leaked from an electronic information equipment, Concretely, a hierarchical extended regression analysis method reflecting various type correlation information is theoretically derived by introducing an expression of multi-variate probability distribution in an orthonormal expansion series form. The effectiveness of the proposed theory is experimentally confirmed too by applying it to the observed data leaked from VDT in the actual working environment,

257 Click here to view scanned manuscript ICSV5 Paper Abstract A Prediction Method for the Stochastic Response of Complicated Soundwall Systems on an Intensity Scale Without Introducing any Artificial Error Criterion Authors: Naomitsu Takaki, Hiroshima-Denki Institute of Technology, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2095, paper no. 179 Abstract: In the actual situation of measuring an environmental noise, it is very often that only the resultant phenomenon fluctuation contaminated by an additional noise of arbitrary distribution type can be observed. Therefore, for the purpose of predicting the output response probability of acoustic system with an arbitrary stochastic input in the presence of the additional noise, it is necessary to find some new stochastic signal processing method reflecting the effect of the above additional noise fluctuation. In this paper, first, a relationship between the system output excited by a specific stochastic input of reference type and an arbitrary random input without the additional noise for an arbitrary acoustic systems is introduced in the form on an intensity scale. Next, a relationship between the system output excited by an arbitrary stochastic input in the absence and that in the presence of the additional noise is also introduced in the form on an intensity scale. Then, based on these relationships, a new prediction method of the system output for the arbitrary acoustic systems with the additional noise is proposed especially by use of the observed data excited by the specific stochastic input of reference type with the additional noise. Finally, the effectiveness of the proposed method is confirmed experimentally too by applying it to the actual type sound wall systems.

258 Click here to view scanned manuscript ICSV5 Paper Abstract An Evaluation Method of the Complicated Acoustic Sys- tem Based on the Neural Networks Reflecting the Sta- tistical Structures Authors: Noboru Nakasako, Kinki University, ( Japan) Yasuo Mitani, Fukuyama University, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2103, paper no. 149 Abstract: An actual sound environment often shows complicated fluctuation patterns apart from a usual Gaussian type. Various evaluation procedures for the sound environment were methodologically proposed, owing to the variety of phenomena and the complexity of human response to them. It is very difficult to evaluate precisely the proper characteristics of complicated systems only from a physical viewpoint based on the structural mechanism. In such situation, a regression analysis function is usually employed between the input and the output fluctuations especially under the assumption of Gaussian property for the input- output fluctuations and/or the usual least squares error criterion. Furthermore, the extended regression analysis method which we previously reported was necessarily reduced in a complicated mathematical form, though it could utilize the lower and higher order correlations on the basis of Bayes’ theorem. This paper describes a regression analysis matched to the prediction of the output response probability for complicated sound environmental systems by introducing a hierarchical neural network with statistical structure. Then, based on the estimated result, the output probability can be easily predicted for the same system with arbitrary input signal. Finally, the effectiveness of the present method is experimentally confirmed by applying it to the actually observed data.

259 Click here to view scanned manuscript ICSV5 Paper Abstract A Precise Estimation Method Matched to Digital Level Measurement for the Probability Distribution of Sound, Light and Electromagnetic Fluctuations Leaked From VDT Authors: Yasuo Mitani, Fukuyama University, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2111, paper no. 148 Abstract: In an actual measurement of random fluctuations, e.g., sound, light and electromagnetic wave fluctuations, the measured data are very often processed in a level-quantized form at discrete time intervals. This is because various statistical evaluations and extraction of the lower and/or higher order statistical information (e.g., mean, variance, median, higher order moments, 90% range, etc., sometimes a quasi- peak value) become easier by use of a digital computer. In this paper, a unified explicit expression for the probability function with level-quantized random variables for an arbitrary random fluctuation is theoretically derived in the general form of a statistical orthogonal expansion series. Next, based on this general theory, a new procedure for estimating the precise level distribution on the basis of information on the moment statistics calculated especially from roughly quantized level data is proposed. Finally, the effectiveness of the proposed theoretical method is experimentally confirmed by applying it to the actual data measured in front of VDT under the working situation.

260 Click here to view scanned manuscript ICSV5 Paper Abstract A Dynamic Estimation Method of Low-frequency Objec- tive Sound in the Outdoor Measurement Contaminated by Wind Noise Authors: Yoshiaki Takakuwa, Hiroshima-Denki Institute of Technology, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Masafumi Nishimura, Hiroshima - Denki Institute of Technology, ( Japan) Hideo Minamihara, Okayama University of Science, ( Japan) Volume 4, page 2119, paper no. 146 Abstract: This paper describes a new method estimating an objective low-frequency acoustic sound contaminated with wind noise in the outdoor measurement. It is a dynamic estimation technique employing a reference band pressure level (BPL) of a particular frequency range of the observation as the basis of the wind noise estimation. First, a conditional probability distribution function (c.d.f) of the wind noise on knowing the reference BPL is shown. Next, a dynamic state estimation technique based on Bayes’ filter is proposed by using the consecutively renewed parameters of c.d.f. of the wind noise as a trial. This method is fairly different from previously proposed state estimation method based on the use of the information on the wind speed observed in the vicinity of the microphone. Because the proposed method becomes comparatively complicated for the practical use, more simplified stochastic estimation methods of the objective sound are also proposed. Finally, the effectiveness of the proposed method is experimentally discussed by employing these simplified methods in this study, especially from the practical view point.

261 Click here to view scanned manuscript ICSV5 Paper Abstract An Estimation Method of Original Stochastic Informa- tion in Non-Gaussian Random Signals With Amplitude Limitations Authors: Hideo Minamihara, Okayama University of Science, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Naomitsu Takaki, Hiroshima-Denki Institute of Technology, ( Japan) Masafumi Nishimura, Hiroshima - Denki Institute of Technology, ( Japan) Volume 4, page 2127, paper no. 145 Abstract: In this paper, an estimation method of the original stochastic information in random noise signals of which the amplitude fluctuation is limited by upper and/or lover levels is proposed for the generalized case of non-Gaussiam random signals. First, an explicit expression of the probability density function for the random signal with amplitude limitations is introduced by using a combination of the well known statistical Hermite orthonormal expansion form and the Diracs delta function. The original stochastic information is closely related to all of expansion coefficients in the probability density expression, and accordingly can be evaluated through the coefficients. That is, by use of this expression, the first, second, ..., nth order moments can be expressed by using the expansion coefficients, the definite integration values of the standard Gaussian distribution and the levels of amplitude limitations. Thus, the expansion coefficients directly connected with the original case with no amplitude limitations can be evaluated by comparing experimental values of the statistical momenta based on the limited observed data with the theoretically calculated moments. The stochastic information for the case with no effect of the amplitude limitation can be estimated through the expansion coefficients. Finally, the effectiveness of the proposed method is confirmed experimentally by means of the digital simulation technique, and by applying it to actual noise data.

262 Click here to view scanned manuscript ICSV5 Paper Abstract A Stochastic Evaluation Method on the Level Crossing of Wave Form for the Road Traffic Noise Authors: Shoji Kodani, Industrial Research Institute, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2135, paper no. 109 Abstract: In this paper, after introducing a fundamental theory for the acuity of arbitrary fluctuating random waves, and some new trials of evaluating statistically and hierarchically the random noise and vibration wave forms of arbitrary non-Gaussian type distribution are proposed, especially by employing the multivariate joint probability density function of series expansion type. First, the counting number that two wave curves contact each other in lower and/or higher order differential forms is estimated and explicit expression of probability distribution on the instantaneous amplitude, velocity and successive higher order differential type physical quantities of the actual random waves can be concretely derived. Especially for the stationary random wave of arbitrary distribution type, a trial toward the statistical evaluation on the locations of level crossing is considered in more detail as a special case, in close connection with the above differential type physical state variables. Finally, the effectiveness of the proposed method has been experimentally confirmed by applying it to complicated fluctuation wave forms of the actual road traffic noise wave.

263 Click here to view scanned manuscript ICSV5 Paper Abstract Static and Dynamic Signal Detection Methods for Road Traffic Noise Environment Based on Fuzzy Observa- tion. Authors: Akira Ikuta, Hiroshima Women’s University, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2143, paper no. 89 Abstract: In the actual sound environment, a specific signal shows various types of probability distribution forms apart from a standard Gaussian distribution due to the diversified causes of fluctuation. Furthermore, the actually observed data often contain some fuzziness due to the existence of confidence limitation in measuring instruments, permissible error in experimental data and a level quantized error in digital observation. In this study, a new estimation theory for a specific signal, based on the observed data containing the fuzziness and the effects of non-Gaussian property is proposed from the static and dynamic viewpoints. More specifically, by applying fuzzy probability to a probability expression with an infinite expansion series form, a static method to estimate the probability density function of the specific signal based on the fuzzy observation data is first proposed. Next, a dynamical method of estimating only a specific signal state embedded in the additional noise (ie background noise) with random fluctuation of non-Gaussian type is theoretically derived especially in a flexible form applicable to these fuzzy observation data. Finally, the varidity and the effectiveness of the proposed method are confirmed experimentally by applying it to the actual road traffic noise data.

264 Click here to view scanned manuscript ICSV5 Paper Abstract Output Probability of an Environmental Vibratory Sys- tem with a Non-linear Feedback Element Authors: Seijiro Hiromitsu, Hiroshima Shudo University, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2151, paper no. 82 Abstract: A statistical treatment for the output probability is proposed by introducing a statistical Lagrange series expansion method, where a general random process of arbitrary distribution type is passed through a time-variant linear environmental vibratory system with an arbitrary non-linear feedback element. A typical example is seen in an environmental vibratory system described by Duffing’s non-linear differential equation. In order to find the effect of non-linear feedback element reflecting an environmental criterion, the explicit expression of the output probability distribution is derived in the general form of non-orthogonal expansion series, reflecting the effects of the forward linear element of the system into the first term. In view of the arbitrariness of the input characteristics, non-linear elements and fluctuation forms of system parameters, the validity of theoretical expression is experimentally confirmed by the method of digital simulation.

265 Click here to view scanned manuscript ICSV5 Paper Abstract A Probabilistic Evaluation Method for Various Type Sound Insulation Systems Based on Kullback’s Information Cri- terion and Mixed Type Non-stationary System Model. Authors: Yoshifumi Fujita, Onomichi Junior College, ( Japan) Mitsuo Ohta, Kinki University, ( Japan) Volume 4, page 2159, paper no. 52 Abstract: In general, it is difficult to find some large scale model only from a bottom up way viewpoint for complicated sound insultion systems like non-parallel double wall or sound-bridge type double wall. Further- more, in the actual environment, the input fluctuates non-stationarily and the output is observed under contamination of the background noise. In this paper, for the above complicated systems with nonstationary random input, a new evaluation method is proposed by newly introducing a multiplicative- additive system model on an intensiy scale. Owing to non-Gaussian property of input, output signals and background noise, the usual identification method such as least-squares error method is not appropriate. So, a new identification method based on Kullback’s information criterion is proposed to deal with the non-Gaussian property. Next, the method predicting the response output probability distribution for arbitrary random input without contamination of the background noise is proposed. Here, according to original non-negative property of intensity quantity, a statistical type Laguerre series expansion is first employed as the output probability distribution form. Its expansion coefficients can be predicted by employing the above identified model. Finally, the proposed method is experimentally confirmed too by applying it to the actual sound insulation systems.

266 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Signal Processing Using Multi-Windowed STFT and Harmonics Sieving Authors: Takahiro Ohnishi, Kogakuin University, ( Japan) Michiko Kazama, Acoustic Consultant, ( Japan) Mikio Tohyama, Kogakuin University, ( Japan) Volume 4, page 2167, paper no. 532 Abstract: This article describes signal estimation and detection using Multi-Windowed Short-Time Fourier Trans- forms (MWSTFT) and harmonics sieving. The MWSTFT proposed here analyzes a signal by using multi- rectangular windows, each of which has a diﬀerent window length. The MWSTFT achieves high frequency- resolution for a short-time windowed compound signal, and the harmonics sieving estimates fundamental frequencies and their harmonics. The harmonics sieving function based on MWSTFT is powerful particularly for fundamental frequency tracking of a non-stationary signal under noisy condition. Com- parison between MWSTFT and conventional STFT methods are mentioned.

267 Click here to view scanned manuscript ICSV5 Paper Abstract Blind Dereverberation Using an Iterative Short-Time Cep- strum Subtraction Method Authors: Jean S. van Eeghem, Kogakuin University, ( Japan) T. Koike, NTT Advanced Technology, ( Japan) Mikio Tohyama, Kogakuin University, ( Japan) Volume 4, page 2175, paper no. 376 Abstract: When the cepstrum domain contributions of a desired dry-speech signal and an unknown transfer function (TF) are divided between a low-time and a high-time region, blind dereverberation is shown to be achievable (A.V. Oppenheim, R.W. Schafer. Digital signal processing, 1975). However for a general room transfer function, the contribution to the complex cepstrum will be spread over the entire cepstrum region. The authors present a blind dereverberation method that is applicable for general types of TF’s. This method is based on the fact that the contribution of the TF is fixed, i.e. compared to that of the speech, for neighboring frames. Processing the reverberant signal for short-time frames allows a recursive scheme to remove the equal TF cepstrum contributions from consecutive frames. The presented method is found to be robust for changes in the TF. Although short-time frames are processed, the effects of amply longer TF’s can successfully be separated form the reverberant speech. However additional processing is required, due to noise occurrence related to short-time frame processing. When extended to semi-online processing the identification of the TF is also possible.

268 Click here to view scanned manuscript ICSV5 Paper Abstract Analysis and Visualization of Room Acoustic Chaos Authors: Yoh-ichi Fujisaka, Kogakuin University, ( Japan) Mikio Tohyama, Kogakuin University, ( Japan) Akira Sugimura, Konan University, ( Japan) Volume 4, page 2181, paper no. 375 Abstract: In a 2-dimensional wave field under irreguiar shaped boundary conditions, the orbit of a sound ray has an instable chaotic motion. For wave theory, the spacing distribution of the neighboring eigenvalues is not degenerated due to the repulsion effects but follows a Wigner distribution in irregular systems. We analyze chaotic characteristics of irregular systems by both wave theory and ray theory. In wave theory, we investigate the higher eigenmodes in an irregular system by using the Finite Element Method (FEM). In ray theory, we visualize chaotic properties of the ray propagation trajectories in a chaotic wave field. As a result, it has been clarifiedthat the trajectory of the billiard problem with a stadium boundary condition has the same sensitivities to the initial conditions as does the mapping process on a logistic map does. We also discuss the transfer function between a sound source and a receiving point in the chaotic field.

269 Click here to view scanned manuscript ICSV5 Paper Abstract Towards More Effective Prediction Of On-Road Wind Noise Characteristics From Wind-Tunnel Tests Authors: Peter O’Shea, Royal Melbourne Institute of Technology, ( Australia) Simon Watkins, Royal Melbourne Institute of Technology, ( Australia) Christian Peric, Royal Melbourne Institute of Technology, ( Australia) Bruce Sloss, Royal Melbourne Institute of Technology, ( Australia) Volume 4, page 2189, paper no. 340 Abstract: The airflow around a moving car results in wind noise which is partially transmitted into the cabin. With the trend towards quieter cars, this wind-generated noise can dominate other noise sources. Standard methods of developing car geometries (often with the aim of minimising wind noise) are based on tests in smooth-flow wind tunnels, rather than by road trials. However, it has been noted that wind noise sounds different in the two test environments. This paper sets out to characterise these acoustical differences. Higher-order spectral statistics and wavelet analysis have been utilised and significant variations were found. Ultimately, it is hoped that such analyses can be used to compare wind noise predicted from smooth flow wind-tunnel data (utilising a knowledge of the turbulent velocity fluctuations in the atmosphere) with data measured under turbulent on-road conditions.

270 Click here to view scanned manuscript ICSV5 Paper Abstract Spectral Estimation Errors When Using FFT Analysers Authors: Thomas Lago, University of Karlskrona/Ronneby, ( Sweden) Ingvar Claesson, University of Karlskrona/Ronneby, ( Sweden) Volume 4, page 2197, paper no. 297 Abstract: An FFT analyzer is often used for spectral estimation. In theory, either a pure sinusoid or white random noise is used. In these two cases it is easy to make an estimate that is correct by using power spectra or power spectral density scaling respectively. In real life, however, signals are likely to be composed of more than one class of signals. This is especially common in the sound and vibration area. Without an a-priori information about the signal, large errors, often several hundred percent are likely. This paper addresses these estimation problems, and covers some of the theoretical background. Easy to use "rules of thumb" are given, that make it possible to verify when a correct estimation has been found. Examples are given using both authentic and synthetic. This type of problem is normally not handled in the text books, and therefore there is a need for raising this issue, especially from a practical point of view, since many engineers are not aware of the problem. From a strict theoretical point of view the problem does not exist, but in reality, if the problem is not dealt with, the consequences can be devastating.

271 Click here to view scanned manuscript ICSV5 Paper Abstract A Qualitative Dynamics-Based Discrete Holographics Method for Vibration Signal Analysis Authors: Fengfeng Xi, Integrated Manufacturing Technologies Institute, ( Canada) Volume 4, page 2205, paper no. 245 Abstract: Presented in this paper is a graphic method called discrete holographic method which can effectively reveal distinct features from the plethora of vibration data. The method is developed based on the theory of qualitative dynamics, subject of which is to extract in a qualitative sense the characteristics of the underlying dynamics that governs the behavior of a dynamical system. The proposed discrete holographics is constructed in the three-dimensional space by three sets of vibration data called visible vectors, sampled by time delays. It is shown that the number of visible vectors sufficient for vibration signal analysis is three, which is proposed to construct the discrete holographics. The proposed method is used to analyze various types of vibration signals including transient signals, modulated signals, repet- itive signals, etc. The results show that this method can effectively extract the characteristics of different types of vibration signals.

272 Click here to view scanned manuscript ICSV5 Paper Abstract Methods for Computing the Passive Wideband Cross Ambiguity Function Authors: Kam W. Lo, Defence Science and Technology Organisation, ( Australia) Brian G. Ferguson, Defence Science and Technology Organisation, ( Australia) Volume 4, page 2213, paper no. 131 Abstract: For a fast moving acoustic source in proximity to a pair of widely spaced sensors, the conventional cross correlation method results in poor time delay estimates because the signal received by each sensor experiences a different degree of time scaling. The correct procedure for time delay estimation in this case is to match the time scales of the two received signals, prior to cross correlating them. In practice, the relative time scale between the two signals is not known a priori and hence it must be estimated jointly with the time delay. This can be done by evaluating the passive wideband cross-ambiguity function. Four different methods are described for computing this function. The most efficient method is applied to synthetic acoustic data which simulate the outputs of three widely spaced microphones during the low altitude transit of a jet aircraft. The resulting time delay estimates are used to calculate the angular trajectory of the aircraft during the transit.

273 Click here to view scanned manuscript ICSV5 Paper Abstract A Proof of the Variance Formula for the Total Crossing Time of a Continuous Random Sound Signal With Re- spect to a Fixed Level Authors: Alois Heiss, Bavarian Ministry of Environmental Protection, ( Germany) Volume 4, page 2221, paper no. 80 Abstract: For a quality controlled application of the percentile sound evaluation index LX , its accuracy, limited by the stochastic level fluctuations, should be quantified. This is achievable by determining first the variance of the partition of the signal ampli-tude with respect to a fixed level, the expectation value of Lx . Then the percen-tiles spread itself is accessible through the cumulative level distribution. As is still to be done, this paper presents a comprehensible proof of the partition variance formula, which is of fundamental importance for the evaluation of the Lx - confidence limits. Given a number of crossings within a given measurement time interval the probability that a definite total of the single continuous over-shoots, i. e. crossing up time intervals occurs, depends as on the stochastic systems crossings up as on its crossings down, and further on the probability density function (p. d. f.) of the crossing number. Above an easily practicable mi-nimum crossing number the p. d. f. of the total crossing time, and so of the parti-tion itself, can be presented explicitly and straightforward in microstatistic terms applying the Central Limit Theorem of Statistics. Then step by step integration of the variance definition equation leads to the already known and applied final result.

274 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Intensity and its Measurement Authors: Finn Jacobsen, Technical University of Denmark,, ( Denmark) Volume 4, page 2231, paper no. 458 Abstract: The sound intensity method is one of the most significant developments of the past twenty years in the technology of noise control enginnering. The method is now generally recognised as a ’mature technology’, which is reflected in the fact that several international and national standards for sound power determination using sound intensity and for instruments for such measurements have been issued in the past few years. The paper summarises the basic theory and gives an overview of the state of the art with particular emphasis on recent developments in the field. It describes and discusses the sources of error in measurement of sound intensity and the resulting limitations imposed on various applications of such measurements. Finally, some unresolved problems are mentioned, and the possibility of improving the instrumentation is discussed.

275 Click here to view scanned manuscript ICSV5 Paper Abstract A Critical Revision of ISO Standard 9614-1: Determi- nation of Sound Power Levels of Noise Sources Using Sound Intensity Authors: Monica Carfagni, Universita di Firenze, ( Italy) Marco Pierini, Universita di Firenze, ( Italy) Volume 4, page 2247, paper no. 339 Abstract: Experimental testing was performed to investigate the validity of ISO Standard 9614-1 for determining the sound power of noise sources using sound intensity at discrete points. Among the conditions varied during testing were environmental geometry, source position, background noise, and measurement surface. On the basis of this investigation and extensive industrial testing, a critical revision of the standard has been written with the intent to eliminate the ambiguity and repetitiveness encountered in the original version.

276 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Intensity Vector Fields in Relation to Different Reference Signals Authors: Orjan Johansson, Lulea University of Technology, ( Sweden) Volume 4, page 2255, paper no. 96 Abstract: 3D-intensity measurements may be used for source localisation. There is, however, a complex relation between the near field intensity estimate and the sound pressure in the far field. Another complica- tion is that the intensity field near a complex structure may be a combination of direct radiation and interference from coherent secondary sources. This is of particular interest when measuring in narrow bands because almost no frequency smearing effect occurs. In this paper, the multivariate technique partial least squares (PLS) regression, is applied for evaluating and interpreting intensity measurements in narrow bands in relation to different reference signals, such as sound pressure in the far field. The PLS method allows correlation in both the frequency and spatial domains. The method is tested and validated experimentally, by studies of a complex but controlled source model with partially correlated sources, in anechoic condition. It is concluded that a decomposition of the intensity vector field in so called principal components enhances the identification of inherent noise sources. The possibility of modelling the intensity vector field in relation to different reference signals reveals a better understanding of the relationship between the partly coherent near field and a specific position in the far field.

277 Click here to view scanned manuscript ICSV5 Paper Abstract A Method to Correct the 3D Active and Reactive Sound Intensity Vectors Using a Rotating 1D Probe in an Un- steady Acoustic Field Authors: Christophe Picard, Laboratoire d’Etudes Aerodynamiques, ( France) J.C. Patrat, LEA, ( France) A. Duran, LEA, ( France) H.S. Na, KHRC, ( Korea) J.C. Rebillat, LEA, ( France) Volume 4, page 2263, paper no. 499 Abstract: A well-known unidirectional probe to which a rotating motion is imparted can measure the three components of the sound intensity vector. Such a sequential measurement procedure produces some scattering and bias errors when the acoustic field is unsteady. During the measurement period, the magnitude of the physical phenomenon is supposed to vary but not its geometric properties. This leads to a simple calculation of these errors and an optimal estimation of the sound power level of the source which is used to correct the active and the reactive sound intensity vectors. For a random steady field, the same method of correction reduces the scattering of the measurements. Theoretical and experimental studies under laboratory conditions verify the effect of the correction even in a reactive field. We also show that in the case of noise emission by a short-duration supersonic jet, the same scattering reduction thus allows a more accurate localization of the intensity vectors.

278 Click here to view scanned manuscript ICSV5 Paper Abstract On the use of the Sound Intensity Method for Detecting Noise Sources near the Reflecting Planes Authors: Sung-Chon Kang, Korea Advanced Institute of Science and Technology, ( Korea) Jeong-Guon Ih, Korea Advanced Institute of Science and Technology, ( Korea) Volume 4, page 2271, paper no. 86 Abstract: The problems in the identification and localization of noise sources using the sound intensity method are dealt with for the reactive field. For these purposes, a three-dimensional model structure resembling the engine room of the passenger car is considered. The model contains complicated noise sources distributed within the small space, which includes the narrow, connected, reflecting planes constructed with rigid boxes. In addition, a small clearance exists between the structure and the reflecting bottom. The sources are actually hanging in the space over this rigid bottom. For this model, the near field acoustic intensity is calculated scanning over the upper plane opposite to the bottom by using the acoustic boundary element method. The effects of relative source phases, frequencies, and locations are investigated. It is observed that the application of sound intensity method without proper care in this situation can yield the detection of fake sources. Therefore, the sound intensity scanning over the engine room upper, with its hood open, may indicate the false positions or components as noise sources. The field reactivity has to be checked and the care should be attended in this type of measurement using the sound intensity methods.

279 Click here to view scanned manuscript ICSV5 Paper Abstract Energy Flow and S.E.A. At Low Modal Overlap Authors: Brian R. Mace, The University of Auckland, ( New Zealand) Volume 4, page 2279, paper no. 415 Abstract: This paper concerns energy flow and statistical energy analysis (SEA) models of structural vibrations when modal overlap is small. In this circumstance the accuracy of SEA predictions is often poor. Partic- ular reference is made to equipartition of energy (i.e., uniform energy density or modal energy throughout a system). It is seen, from both wave and modal analyses, that equipartition of energy does not occur in mechanical systems. Some wave analyses are reviewed. A global modal analysis is performed for the case of low modal overlap. Examples are discussed, and, in particular, results for a system comprising three coupled plates are presented. Energy density differences between different subsystems in a system are seen to exist when the modal overlap is low. This arises, in wave terms, when transmission coefficients differ from unity and, in modal terms, from the localisation of global modes within the susbsytems. Both these tend to contain energy in the driven subsystem. Effects tend to decrease for subsystems that are well coupled and irregular and if the system has many subsystems, many of which are excited.

280 Click here to view scanned manuscript ICSV5 Paper Abstract Predictive Statistical Energy Analysis and Equally Spaced Point Connections Authors: Ken H. Heron Volume 4, page 2287, paper no. 318 Abstract: Using the wave approach, the theoretical prediction of Statistical Energy Analysis plate-to-plate coupling loss factors is based on calculating the random incidence transmission coefficient matrix associated with the equivalent infinite line junction. The 4x4 semi-infinite line wave dynamic stiffness of each plate is used to calculate the transmission coefficient for a particular angle of incidence; these angle transmission coefficients are then numerically integrated to obtain the required random incidence transmission coefficient. Many line connections in real engineering structures are in fact a series of equally spaced point connections. The spacing of these points is often neither large nor small in comparison to structural wavelengths. Furthermore each connection point may itself exhibit dynamic behaviour such as when point isolators are employed. This paper presents a theoretical solution to this problem based on the Fourier decomposition of the connection line into a series of true line connections each with a different trace wavenumber. The cross transfer matrix of a single point connection is then incorporated into the theory to model its dynamic behaviour. Experimental results are then compared with this theory using a two-plate assembly with an I-sectioned connecting beam and with various numbers and types of point connectors.

281 Click here to view scanned manuscript ICSV5 Paper Abstract Statistical Energy Analysis of a High Speed Elevator Cab and Frame Authors: Charles D. Coﬀen, United Technologies Research Center, ( U.S.A.) Larry Hardin, United Technologies Research Center, ( U.S.A.) Tricia Derwinski, Otis Elevator Company, ( U.S.A.) Volume 4, page 2295, paper no. 457 Abstract: An analytic prediction model was developed to identify the dominant paths of broadband (100 - 5000 Hz) acoustic energy transmission into an elevator cab enclosure. Statistical Energy Analysis (SEA) was used as the method, including analytical SEA, test based SEA, and panel transmission loss experiments. The model was validated statically with vibration and acoustic measurements made in Otis’ Ride Quality Evaluation Facility, and operationally with measurements made in Otis’ Bristol Research Tower. The validated AutoSEA model has provided a new means of identifying and quantifying the dominant noise sources and paths for vibro-acoustic energy ﬂow through the elevator cab. This analysis has also demonstrated potential as a design tool for evaluating cab enclosure noise reduction concepts.

282 Click here to view scanned manuscript ICSV5 Paper Abstract New Procedure of Vibration Analysis Using Statistical Energy Analysis: Case of Box-Like Structure Authors: Minoru Kamata, University of Tokyo, ( Japan) Toru Yamazaki, University of Tokyo, ( Japan) Kazuaki Kurosawa, University of Tokyo, ( Japan) Shinichi Ohno, University of Tokyo, ( Japan) Volume 4, page 2305, paper no. 422 Abstract: This paper describes a new procedure which eases the SEA model construction (estimation of loss factors) and enables the prediction of vibration energy distribution in subsystems. In the construction of SEA model, the power flow between subsystems are directly measured using the structural intensity measurement. Compared with the power injection method which is popular for determining factors, this approach is easier because only one subsystem in the objective system is required for excitation. The SEA model gives the prediction of energy levels of subsystems, but the distribution of energy inside of a subsystem is unknown. Then, in order to predict the distribution, we use the finite element analysis in which an objective subsystem is modeled. This paper shows how the boundary and the excitation conditions in FEM are determined. These approach is tested to predict the vibration energy and the energy distribution of a box-like structure both numerically and experimentally. As a result, the SEA model constructed by the structural intensity measurement is good for energy prediction, and the finite element model of ever-y subsystem gives us the proper prediction of energy distribution.

283 Click here to view scanned manuscript ICSV5 Paper Abstract Energy Flow Models From Finite Elements: An Applica- tion to Three Coupled Plates Authors: P.J. Shorter, The University of Auckland, ( New Zealand) Brian R. Mace, The University of Auckland, ( New Zealand) Volume 4, page 2313, paper no. 414 Abstract: This paper is concerned with the prediction of the distribution of vibrational energy throughout a structure. The paper illustrates how the results from a finite element model can be rephrased in terms of subsystem powers and energies using component mode synthesis. Equations are derived for the response, and frequency averages are obtained from them analytically. The technique is then illustrated by considering a system comprising three coupled plates, each plate being coupled along two of its edges. Ensemble and frequency averaged numerical results are compared with SEA predictions. It is seen that SEA predictions can be in error, this being attributable to coherence effects which arise because the system is strongly coupled, and the effects of averaging over narrow frequency bands.

284 Click here to view scanned manuscript ICSV5 Paper Abstract The Limitation in the Sea Prediction of Power Trans- mission and Energy Distribution Authors: Ruisen Ming, The University of Western Australia, ( Australia) Jie Pan, The University of Western Australia, ( Australia) Volume 4, page 2321, paper no. 372 Abstract: This paper presents a numerical study of SEA prediction accuracy in a coupled plate system. It was shown that the parameters controlling the prediction accuracy are the geometric mean of modal overlap factor M and number of coupled modes N in the frequency band of analysis. In the low frequency bands where few coupled modes are present, both prediction error and standard deviation of numerical results are large. The "travelling wave" model and SEA may not be appropriate. In the medium frequency bands where N is neither large nor small, the "travelling wave" model and SEA are applicable but their prediction errors are not negligible. The prediction error and standard deviation generally decrease as M increases. However, M cannot be used as a sole parameter for judging the prediction accuracy. For same M but different dissipation loss factors, the prediction errors could be different. The increase of modal number can reduce fluctuation and standard deviation, but cannot reduce the prediction error. The increase of dissipation loss factors can reduce not only fluctuation and standard deviation but also the prediction error. In the high frequency bands where both M and N are large, the standard deviation becomes small and the prediction error is negligible.

285 Click here to view scanned manuscript ICSV5 Paper Abstract Method to Determine Structure-Borne Noise Level From Machinery In Sea Application Authors: Sang R. Kim, KIMM, ( Korea) Jae S. Kim, KIMM, ( Korea) Hyun S. Kim, KIMM, ( Korea) Hyun J. Kang, KIMM, ( Korea) Volume 4, page 2329, paper no. 315 Abstract: It is well known that Statistical Energy Analysis (SEA) is one of very attractive analytical methods to solve shipboard noise problems. With reasonable successes, many applications of SEA to shipboard noise prediction have been reported. However when one wishes to obtain theoretical preductions by using SEA in practical systems, he will find difficulty in modeling of source systems, that is, foundations where to place main engine, generator, compressor, and so on. Also, he will find that it is hard to determine the amount of power flow from machinery to structures. In this paper, SEA of a simple foundation model was carried out using three kinds of the estimated amount of power flow from source; a averaged square-velocity level, mobility method, and actually measured power. The comparison of these results is presented. That comparison shows a method to get structure-borne noise power from the combination of machinery and foundation. This preduction method gave a good result for a air-compressor mounted on a model foundation. The method is expected to give a reasonable power output in practical problems.

286 Click here to view scanned manuscript ICSV5 Paper Abstract Combined FEA/SEA Vibration Analysis Authors: Anders M. Wilson, Chalmers University of Technology, ( Sweden) Volume 4, page 2337, paper no. 239 Abstract: The Finite Element Method (FEM) is frequently and mostly successfully used to model low frequency vibration behavior in built up structures. Although this tool has proven successful in many areas, it has been found to have severe limitations for noise and high ferquency vibration prediction. The Statistical Energy Analysis (SEA) technique has become increasingly interesting and important for high frequency vibration and noise prediction. Up till now, the techniques mentioned above have mostly been used separately. Since FEM and SEA have their compoutational strengths in different frequency ranges, an analytical means of combining these two methods and taking advantage of each method’s strengths is sought for in the current project. The procedure used to combine SEA and FEM, is separate modeling of the different regions of the structure according to modal density and structural configuration, and then applying an energy based optimization to fullfill local and global restraint equations. To allow large FEM models in the analysis and to extend the frequency range for the part analyzed by FEM, dynamic substructuring is incorporated in the analysis.

287 Click here to view scanned manuscript ICSV5 Paper Abstract Uncertainty of Vibroacoustic Behaviour of Industrially Identical Structures - A New Challenge for Structural Acoustic People Authors: Jean-Louis Guyader, INSA de Lyon, ( France) E. Parizet, Renault D.R., ( France) Volume 5, page 2347, paper no. 534 Abstract: Some experiments on populations of industrially identical structures have shown a large variation of their vibroacoustic behaviour. They indicates that small structural defects can lead to strong differences on vibration and acoustic radiation properties. This problem is presently important for automotive industry, because it leads to a non negligible percentage of cars that have a non perfect acoustic. The phenomenon was also theoretically shown on populations of coupled plates having small defects in their junction angle ; and was called hypersensitivity. The explanation of such behaviour is a very strong change in the coupling of flexural and in plane motions, when the angle of connection vary. However, the phenomenon only exist of quasi flat junctions. An experiment made on real body parts of a car will be presented to demonstrate that small geometric imperfections due to the process of assembling substructures, produce the hypersensitivity phenomenon. The experiment was based on mobility measurements. We started with simple parts then coupled together in order to build a polpulation of complex structures. We will show in the presentation, at what level of the process of conecting substructures the hypersensitivity appears. A last part of the presentation, will be devoted to a theoretical approach of non perfectly described structures. We will present how the uncertainty on the equation of motion, characterized through a residual energy, is related to the uncertainty on localization of resonance frequencies.

288 Click here to view scanned manuscript ICSV5 Paper Abstract Machine Bases as Structure-Borne Sound Sources Authors: Barry M. Gibbs Volume 5, page 2359, paper no. 385 Abstract: The structure-borne sound power delivered by a vibrating machine into a supporting or connected structure is determined by both the machines activity and the dynamic characteristics at the contacts. It is a relatively simple matter to measure activity in the form of velocity at the contacts of the free source under normal operating conditions. The structural dynamics are not so easy to predict or measure and the full mobility matrix method of prediction is data and time consuming. However, visual inspection of the measured nobilities of machine bases can give engineering insights on how best to treat machines as multi-point and multi-component sources. Mobility data from a measurement survey of a range of machinery bases is described and results compared in order to conﬁrm the generality of the point and transfer mobilities. The role of moments also is discussed and although it is demonstrated that it is much less likely that generalisations can result, the special but common case of building services machinery on concrete plantroom ﬂoors is shown to allow some simplifying assumptions.

289 Click here to view scanned manuscript ICSV5 Paper Abstract Smart Sensors for Measuring the Acoustic Power Mode of a Planar Structure Authors: Yoshihiro Kikushima, Mechanical Engineering Laboratory, ( Japan) Nobuo Tanaka, Mechanical Engineering Laboratory, ( Japan) Volume 5, page 2375, paper no. 390 Abstract: This paper considers the design of distributed parameter modal sensors called smart sensors, with a particular emphasis on filtering the combination of appropriately weighted vibration modes providing a specific performance index in control strategy. First, by considering a practicability of the distributed parameter smart sensors using PVDF film sensors, one-dimensional smart sensor is presented. It is found that the approach done by the one-dimensional sensors holds only the necessary condition for sensing the transformed mode. This problem is overcome by introducing multiple one-dimensional smart sensors. Moreover, the design procedure for the multiple one-dimensional smart sensors for measuring the transformed mode is established. Then, an experiment is conducted, demonstrating the validity of the smart sensors. Finally, using the smart sensors, the minimization of the total acoustic power radiated from a vibrating plate is carried out.

290 Click here to view scanned manuscript ICSV5 Paper Abstract A Study of the Transmission of Noise and Vibration in an Aluminium Motor Vessel Authors: Yan K. Tso, Defence Science and Technology Organisation, ( Australia) Ross G. Juniper, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2383, paper no. 386 Abstract: This paper describes an investigation of the noise problem in an aluminium motor vessel. The problem was due to the high noise level in the work deck area which exceeded operational health and safety (OH&S) requirements by 9 dB at cruising speed. It was identiﬁed in this paper that the deck noise was due to contributions from three sources. These sources were: (i) the radiated noise due to vibration of the deck structure, (ii) the noise transmitted from the engine room to the deck and (iii) the noise transmitted from the exhaust vent to the deck. Various control measures for reducing the deck noise are discussed and preliminary results on deck noise measurements of the modiﬁed vessel are presented

291 Click here to view scanned manuscript ICSV5 Paper Abstract Structural Sensing of Sound Transmission into a Cavity for Active Structural-Acoustic Control Authors: Ben Cazzolato, University of Adelaide, ( Australia) Colin H. Hansen, The University of Adelaide, ( Australia) Volume 5, page 2391, paper no. 349 Abstract: The problem of actively minimising the transmission of harmonic sound through a curved panel into a contiguous cavity using structural sensors is investigated both numerically and experimentally. It is well known that a control system that simply aims to minimise the structural vibration does not necessarily lead to a reduction in sound transmission. However, by considering the dynamics of the coupled system, it is possible to derive an orthonormal set of structural "radiation modes" which are orthogonal with respect to their contribution to the acoustic potential energy of the internal coupled acoustic space. Minimisation of the amplitudes of these "radiation modes" is guaranteed to result in a reduction of the interior potential energy, in contrast to minimising the normal structural modes. Sensing of the orthogonal sets of "radiation modes" is accomplished by using "smart sensors" made from either shaped PVDF ﬁlm or a linear combination of accelerometers, adjusted to sense a particular radiation mode.

292 Click here to view scanned manuscript ICSV5 Paper Abstract Axisymmetric Transfer Functions along a Fluid Filled Elastic Tube Authors: Roger J. Pinnington Volume 5, page 2403, paper no. 190 Abstract: The equations of motion of a fluid-filled tube moving with axisymmetric motion are described. This leads to a dispersion plot describing the frequency dependence of four wavenumbers. One wave is predominantly controlled by the fluid and wall stretching, the others by wall motion. Homogeneous rubber tubes were found to soften with increasing pressure while braided rubber tubes stiffened significantly with increasing pressure.

293 Click here to view scanned manuscript ICSV5 Paper Abstract Approximating Eigensolutions Of Distributed Structures Using Adjustable Base Functions Authors: Jie Pan, The University of Western Australia, ( Australia) Volume 5, page 2411, paper no. 184 Abstract: The prediction of resonance frequencies and mode shapes of distributed structures requires high convergence rate and accuracy. When approximated methods, such as the Rayleigh-Ritz method, are used, these requirements are largely dependent upon the base functions used to express the mode shape functions. This paper shows that while base functions selected to satisfy all the boundary conditions of the structure, their linear independency may be reduced. This will results in ill conditioned mass matrix in the generalised eigenequations (large matrix condition number) and prediction error. On the other hand, the base functions with good linear independent property may not satisfy part of the boundary conditions. This paper propose the use of adjustable base functions to allow the selection of the base functions capable of satisfying the all boundary conditions and keeping the condition number of the mass matrices suﬃciently small. As a result, the two requirements can be simultaneously satisﬁed.

294 Click here to view scanned manuscript ICSV5 Paper Abstract Radiation From Partially Excited Plates Authors: R.A. Novak, Ingemansson Technology AB, ( Sweden) Volume 5, page 2419, paper no. 164 Abstract: A residential building with high sound insulation was recently built in Stockholm, This building was designed to have a sound insulation between the apartments, both horizontally and vertically, that was substantially higher then normal buildings in Sweden. Since the building costs are high this new building should at the same time not be more expensive to build. In order to achieve this a special type of supporting structure was used. In connection to this project some theoretical and experimental studies were made, One of these studies concerned the sound insulation of light-weight double walls, which were used between the apartments, and another concerned the radiation factorof finite plates. In this paper,an evaluation of the influence of the plate size on the radiation factor and the sound reduction index is presented. The radiation factor is obtained from the Fourier transform of the plate velocity over the excited area of the plate and it is presented for both rectangular and square plates of different sizes.

295 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Radiation from Structures: the Frequency Av- eraged Quadratic Pressure Prediction Authors: Jean-Louis Guyader, INSA de Lyon, ( France) Thierry Loyau, INRS, ( France) Volume 5, page 2429, paper no. 71 Abstract: The prediction of noise radiated from machinery is a very difficult problem because of the complexity of the vibration fields producing noise. The classical Green’s function formulation solve the problem using pure tone signals wich necessitate a very good knowledge of vibrations, including modulus and phase, this is quite impossible in machinery due to structural complexity. The necessity of finding appropriate methods to predict radiation from machinery is then obvious. Our idea is to predict the acoustical behaviour using a quantity not so sensitive as the pure tone pressure radiated. As in S.E.A. we will introduce frequency band average quatratic quantity, in order to get a method that reduces the information necessary for calculations and also the computing time. The theory for a simply supported baffled plate was previously presented in [1], [2]. The main assumption was dicussed and prediction compared with classical calculations and experimental data. The present paper extend the method to the case of the hood of a machinery internally excited. Comparaison of theoretical and experimental data on a circular saw will be shown in order to see the limitation of the method when applied to non plane structures.

296 Click here to view scanned manuscript ICSV5 Paper Abstract The High-Frequency Vibration and Sound Radiation of a Homogeneous Plate With Internal Losses Authors: V.U. Kirpichnikov, Krylov Shipbuilding Research Institute, ( Russia) A.A. Juravleva, Krylov Shipbuilding Research Institute, ( Russia) Lyudmila Ph. Drozdova, Baltic State Technical University, ( Russia) Volume 5, page 2437, paper no. 461 Abstract: The high-frequency forced vibrations of a homogeneous plate that contacts with acoustic media are investigated. The roots values of the dispersion equation of the plate bending vibration with account for the shear and rotary inertia of it cross section and for internal losses were analyzed. It is showed the frequency range where this equation has not a single but three pairs of real roots appears just when losses are equal to zero. The waves caused by the plate - media cooperation dont disappear but transmit along the plate with decreasing that is proportional to the loss value when the internal losses are counted. A physical meaning of wave transforming at some frequency ranges when the fast decreasing waves transform to the nonuniform waves is explained. The process of the acoustic pressure forming near the plate by elastic waves is investigated at the case when the pressure is a sum of the steepest path integral and the line integral around the dispersion equation poles that are at the physical Riman sheet. The four areas of the main inﬂuence of a continuos spectra and a discrete wave spectra are established.

297 Click here to view scanned manuscript ICSV5 Paper Abstract Sound Radiation of Plate Excited by a Force of an Arbi- trary Angle Direction Authors: V.U. Kirpichnikov, Krylov Shipbuilding Research Institute, ( Russia) V.V. Savenko, Krylov Shipbuilding Research Institute, ( Russia) Lyudmila Ph. Drozdova, Baltic State Technical University, ( Russia) Volume 5, page 2443, paper no. 460 Abstract: An analytical solution of sound radiation of an infinite homogeneous plate is derived. The plate is in contact with acoustic media by a single surface and is excited by a point force directed at arbitrary angle to it plane. An physical analysis of roots of a dispersion 14-ordered equation of jointed bending and longitudinal-shear plate vibrations is executed. It is estimated that correlation of this type vibrations is caused by an asymmetric reaction of media. A physical meaning of the six components of the farfield sound pressure is presented. The dependencies of this components levels from angles of a force inclination and of a direction to a view point are analyzed for a case of a metal plate vibrations that is contacted with water surface. The differences of the components levels of sound pressure at frequencies that are lower and above the coincidence frequency are showed.

298 Click here to view scanned manuscript ICSV5 Paper Abstract Source Descriptors for Structure-Borne Sound Sources Authors: A T Moorhouse J.M. Mondot, Centre d’Entreprise et d’Innovation, ( France) Barry M. Gibbs Volume 5, page 2449, paper no. 389 Abstract: A source descriptor for structure-borne sound sources is presented which is similar to airborne sound power. It has units of power and is valid for multiple point contact and for moment as well as force excitation. The power delivered when the source is installed is a fraction of this source descriptor and is determined by the degree of mobility matching between source and receiver. Results are presented for a domestic central heating pump and centrifugal fans on various receiver structures.

299 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Analysis of Rotor Bearing Pedestal Systems Authors: N.S. Feng, University of New South Wales, ( Australia) E.J. Hahn, The University of New South Wales, ( Australia) Volume 5, page 2457, paper no. 336 Abstract: In analysing the vibration behaviour of turbomachinery, a problem exists in modelling foundation- pedestal support systems whose natural frequencies are within or close to the operating speed range. Often, a finite element model of the foundation-pedestal support is unavailable and it is impractical to determine its modal properties experimentally. As a first approximation, one could regard the foundation as rigid and replace the pedestals by equivalent supports having mass and stiffness properties which correctly reflect the system unbalance response over the operating range. This paper outlines a method for identifying such pedestal properties for general rotating machinery using measurements of the motion of the pedestals and of the rotor. The proposed technique assumes a knowledge of the stiffness and damping properties of the support bearings (which may be hydrodynamic) but does not require a knowledge of the rotor, nor of the unbalance excitation; but merely that it be sufficient to provide measurable motion data. Numerical experiments show that excellent identification of pedestals is feasible even with the two digit measurement accuracies attainable with field instrumentation, suggesting applicability to practical turbomachinery where there is significant vibration at the pedestals though relatively insignificant vibration in the foundation itself.

300 Click here to view scanned manuscript ICSV5 Paper Abstract Low and Mid-frequency FRF Modelling of Engine Sub- frame and Car Body Interaction for Vibratory and Acous- tical Response Evaluation Authors: Katrien Wyckaert, LMS International, ( Belgium) G. Toniato, CRF, ( Italy) K.Q. Xu, KU Leuven, ( Belgium) Volume 5, page 2465, paper no. 244 Abstract: Thispaper describes the process of obtaining vibratory and acoustical response predictions within the car body, due to engine excitation. The approach that is followed is to model the high modal density vibratory and acoustical behaviour of the car body by a set of measured frequency response functions, while the engine carrying crossmember is represented by a ﬁnite element model. The coupling interaction of the crossmember with the car body is calculated based on FRF based substructuring techniques. The modeling process further includes experimentally derived engine excitation forces. Coupling predictions of crossmember and car body are carried out and design changes evaluated.

301 Click here to view scanned manuscript ICSV5 Paper Abstract Estimation of Surface Mobility of an Infinite Plate for a Square Contact Area by the Finite Element Method Authors: Yuejun Li, Australian Defence Force Academy, ( Australia) Hugh M. Williamson, Australian Defence Force Academy, ( Australia) Jue Dai, Australian Defence Force Academy, ( Australia) Christopher J. Norwood, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2477, paper no. 128 Abstract: Finite element techniques were investigated for determination of surface mobility of an infinite plate excited over a square contact area by a uniform force distribution using the effective point mobility concept. Ordinary point and transfer nobilities were obtained using harmonic response analysis in FEM. Then surface nobilities were calculated for different sizes of square contact area, based upon these ordinary mobilities. The comparison between the numerical FEM results and theoretical prediction shows that the surface mobility obtained by both methods generaIly decreases with increasing area of the square and that both results have dips at intervals in Helmholtz number which are approximate multiples of pi.

302 Click here to view scanned manuscript ICSV5 Paper Abstract Surface Mobility for a Rectangular Contact Region Un- der a Uniform Velocity Distribution Authors: Jue Dai, Australian Defence Force Academy, ( Australia) Hugh M. Williamson, Australian Defence Force Academy, ( Australia) Yuejun Li, Australian Defence Force Academy, ( Australia) Volume 5, page 2493, paper no. 31 Abstract: In the study of structure-borne sound and vibration isolation, mobility is used to reflect the characteristics of power transmission of a supporting structure. When the contact area between an exciting machine and its supporting structure is larger than the governing wave length, surface mobility is applied. Surface mobility is influenced by many factors such as the pattern and frequency of excitation and the dimensions and shape of the contact area. By means of analyses of these factors, the effects of power transmision through the contact area can be obtained under different conditions. In this paper, the effective point mobility and surface mobility over rectangular contact areas, for the assumption of a uniform conphase velocity distribution, are studied. An infinite homogeneous thin plate is chosen as a supporting structure. The resulting force distribution and effective point mobility within the contact area are calculated. Using effective point mobility, surface mobility is also calculated. By this method, not only is the total power transmission calculated from an excitor to the thin platelike support, but also the detailed pattern of power transmission within the contact areas can be predicted.

303 Click here to view scanned manuscript ICSV5 Paper Abstract Variational Formulation by Integral Equations for the Resolution of Vibro-acoustic Problems in a Visco-thermal Fluid Authors: C. Karra, UPRESA CNRS, ( France) Mabrouk Ben Tahar, Universite de Technologie de Compiegne, ( France) Volume 5, page 2501, paper no. 6 Abstract: A total variational formulation of vibro-acoustic interaction between vibrating membrane and a visco- thermal fluid layer was investigated. This formulation combines a new variational formulation by integral equations of the fluid, which taking into account of acoustic and entropic waves coupling, with a classical variational formulation of the membrane. This formulation has been implemented numerically for the problems with revolution geometry. The obtained numerical results are compared to analytical ones developed for three models : perfect fluid model, visco- thermal fluid model which coupling acoustic and entropic waves (developed in this work) and visco-thermal fluid model which coupling acoustic, entropic and shear waves. These comparisons showed the validity of our formulation proposed in this work and the importance of the effects of entropic and shear waves on the damping of modes of coupling fluid- structure system and the decrease of their natural frequencies in the case of the micro-cavities.

304 Click here to view scanned manuscript ICSV5 Paper Abstract Crack Detection in Beams Using Structural Intensity Authors: Christopher J. Norwood, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2511, paper no. 163 Abstract: Vibration analysis techniques have been used for crack detection for many years. Recently much of the emphasis in this area has been on the use of shifts in natural frequency as an indicator of damage. The vibration response of a structure is determined by the mass and stiffness distribution throughout the structure. In a similar manner the structural intensity or power flow in the structure is determined by the mass, stiffness and damping distributions. This paper examines the effect of a crack on the flexural power flow in a beam. Expressions for the transmission and reflection of flexural waves incident on a crack are derived. A fracture hinge representation of the crack is used and the analysis shows that at the crack there is a discontinuity in the reactive intensity. The size of the discontinuity is dependant upon the crack size and the wave number. Experimental measurements of the power flow in a simulated infinite beam with a crack are made using the wave decomposition method. These results confirm the existence of the discontinuity in the reactive intensity at the crack. The use of wave number measurements as a crack indicator was also tested experimentally and found to be superior to intensity.

305 Click here to view scanned manuscript ICSV5 Paper Abstract Bias Errors in Measurement of Vibratory Power and Im- plication for Active Control of Structural Vibration Authors: Mogens Ohlrich, Technical University of Denmark, ( Denmark) E. Henriksen, Technical University of Denmark, ( Denmark) S. Laugesen, Technical University of Denmark, ( Denmark) Volume 5, page 2519, paper no. 150 Abstract: Uncertainties in power measurements performed with piezoelectric accelerometers and force transducers are investigated. It is shown that the inherent structural damping of the transducers is responsible for a bias phase error, which typically is in the order of one degree. Fortunately, such bias errors can be largely compensated for by an absolute calibration of the transducers and inverse ﬁltering that results in very small residual errors. Experimental results of this study indicate that these uncertainties will be in the order of one percent with respect to amplitude and two tenth of a degree for the phase. This implies that input power at a single point can be measured to within one dB in practical structures which possesses some damping. The uncertainty is increased, however, when sums of measured power contributions from more sources are to be minimised, as is the case in active control of vibratory power transmission into structures. This is demonstrated by computer simulations using a theoretical model of a beam structure which is driven by one primary source and two control sources. These simulations reveal the inﬂuence of residual errors on power measurements, and the limitations imposed in active control of structural vibration based upon a strategy of power minimisation.

306 Click here to view scanned manuscript ICSV5 Paper Abstract Conservation of Energy and Model Convergence Using Experimental Spatial Power Flow Authors: Jonathan D. Blotter, Idaho State University, ( U.S.A.) Gary A. Fleming, NASA Langley Research Center, ( U.S.A.) Robert L. West, Virginia Polytechnic Institute & State University, ( U.S.A.) Volume 5, page 2527, paper no. 7 Abstract: Experimental Spatial Power Flow (ESPF) is a non-intrusive spatially continuous laser based technique for extracting the power flow from vibrating strucutres. The ESPF approach retains the spatial representation of the power flow, obtained from analytical models, and represents the actual boundary conditions by using experimental data obtained from a scanning laser Doppler vibrometer. In this paper, ESPF results are compared to the power injected into a simply supported plate which is excited by two shakers placed diagonally across the plate. The two shakers are phased such that one acts as a power source and the other a power sink. The power injected and absorbed by the two shakers is computed from impedance head measurements. Model order convergence capabilities of the power flow computed using the ESPF techniuqe are also demonstrated.

307 Click here to view scanned manuscript ICSV5 Paper Abstract Evaluation of the Effect of Damping Treatment Using Approximated Vibration Mode Shapes Authors: Hisami Ohishi, Kogakuin University, ( Japan) Shinichi Ohno, University of Tokyo, ( Japan) Volume 5, page 2535, paper no. 453 Abstract: Levels of structural vibration reduced by damping treatment can be evaluated by consumption of vibration energy derived from distributions of structural intensity and strain energy. However, it is difficult to estimate accurately structural intensity and strain energy in the structure with damping treatment. In this paper, therefore, we propose a method to estimate more accurately structural intensity and strain energy using the mode shapes which are approximated by superposition of the natural mode shapes of the structure without damping treatment. First, structural intensity and strain energy of the equivalent system of a beam with damping treatment and a damper are calculated by this method, and its accuracy is examined. Then, the effect of damping treatment are discussed based on the distributions of the structural intensity and the strain energy. Finally, validity of this method is examined.

308 Click here to view scanned manuscript ICSV5 Paper Abstract Practical Approach of Structural Intensity Measurement Applied for Box-Like Structure Authors: Toru Yamazaki, University of Tokyo, ( Japan) Minoru Kamata, University of Tokyo, ( Japan) Shinichi Ohno, University of Tokyo, ( Japan) Volume 5, page 2543, paper no. 423 Abstract: The main purpose of structural intensity measurement is the estimation of power propagating through structures and the detection of excitation position. To accomplish these purposes, the intensity flow is measured at many points on structures by a method based on the finite difference approximation which requires five accelerometers (5-transducer array method). And in the detection of excitation position, the wave decomposition method which reveals the effect of evanescence wave field is employed. More- over, to estimate the propagating power, the mean power flow is also calculated using the individual wave amplitudes which are obtained from the wave decomposition method. In this report, our approach described above is investigated using a box-like structure. As a result, the propagating power can be determined by the 5-transducer array method or by the calculation of mean power flow within practical error level. And the approach is also applied to analyse the power flow on vehicle body panels. The results indicate that the approach is effective to know the power flow and to estimate the propagating power, and we can say our approach enables us to analyse the power flow in a certain extent precision.

309 Click here to view scanned manuscript ICSV5 Paper Abstract How Can We Improve Ways To Describe Future Noise Impacts To Decision Makers And The Community? The Lessons From Sydney Airport Authors: David Southgate, Department of Transport and Regional Development, ( Australia) P. Pieruschka, Department of Transport and Regional Development, ( Australia) Volume 5, page 2553, paper no. 442 Abstract: Following the opening of the new third runway’ at Sydney Airport in November 1994 there was a public outcry over the way future noise impacts had been explained during the Environmental Impact State- ment (EIS) process for the project. There was a widespread view that the award winning EIS had been grossly misleading. Using the third runway EIS as an example, this paper examines the weaknesses of the conventional approach to describing noise through cumulative noise indices. Complex averaging’ noise indices can not generally be understood by the layperson and do not provide information in a useful form. Instead the public is seeking information that is more readily digestible. To meet this demand information is being provided on ﬂight paths, the number of noise events per hour, the maximum noise level of each event and the amount of time per day when areas will receive respite’ from noise. Information on daily and seasonal variations in noise exposure is also being provided. This paper shows new approaches to describing aircraft noise exposure that have been trialed in recent formal reports and discusses their potential.

310 Click here to view scanned manuscript ICSV5 Paper Abstract The Noise Impacts Associated with a Major Road In- frastructure Project in a Developing Nation Authors: Stephen Samuels, University of New South Wales, ( Australia) Weeradej Cheewapattananuwong, Department of Highways, ( Thailand) Volume 5, page 2563, paper no. 370 Abstract: Road traffic noise has been an issue of significance within the developed world for many years now. More recently it has been of increasing importance in the developing nations. This is particularly so in the South East Asian region where surging economic growth and development has resulted in considerable expansions to the road transport infrastructure networks. Bangkok, the capital of Thailand, provides a good example of this situation. The city is located on the Easter bank of the Caho Phraya River, with the sister city of Thon Buri situated on the river’s Western bank. Cross river traffic is high and increases dramatically during peak hours. Baromrajchonne Rd is a major arterial road in central Bangkok which is significantly affected by this cross river traffic and therefore a project is under way (at Thai Royal initiation) to upgrade Baromrajchonne Rd by adding several kilometres of elevated section. During construction, traffic congestion has been extreme and this has led to increased traffic noise levels. The paper focuses on this particular traffic noise issue and uses Baromrajchonne Rd as a case study example. Having explored the issue in some detail, the paper culminates with a series of amelioration strategy proposals.

311 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract A Preliminary Traffic Noise Investigation in an Acous- tically Upgraded Dwelling Authors: Tony Circelli, South Australian Environmental Protection Authority, ( Australia) Cecilia Bukutu, South Australian Environmental Protection Authority, ( Australia) Volume 5, page 2569, paper no. 558 Abstract: A preliminary study was carried out to investigate the acoustical effectiveness of residential multiple occupancy dwellings located on North East Road, Adelaide which were designed to reduce the adverse impact of traffic noise. Noise measurements were taken both at night and day. Indoor and outdoor LAeq, LA10, LA90, LA01 and LAmax were obtained simultaneously every 15 minutes over a six day period. The investigation determined both the mean outdoor and internal noise and the resulting mean outdoor to indoor noise attenuation for each noise descriptor. The internal noise levels were compared with selected traffic noise criteria. It was found that the resulting amenity within the acoustically upgraded dwelling was superior to conventional construction dwellings. Resulting internal noise levels generally satisfied the Shire of Hornsby Building Code criterion. However OECD criteria based on the LAeq and the LAmax noise level were exceeded.

312 Click here to view scanned manuscript ICSV5 Paper Abstract Aircraft Noise in Sydney - Community Reaction in Ar- eas Between 15 and 30km North of the Airport Authors: Ernestine M.A. Gross, Macquarie Graduate School of Management, ( Australia) Ah Boon Sim, University of New South Wales, ( Australia) Volume 5, page 2581, paper no. 539 Abstract: The Australian Noise Exposure Forecast (ANEF) system was applied in Sydney in the decision making process which led to the construction of the ’third runway’. After the opening of this runway in November 1994, a predominantly north-south parallel runway mode of operation was adopted. The Environmental Impact Statement for the third runway and the associated Draft Noise Management Plan (DNMP) predicted, on the basis of the ANEF system, and data contained in Hede and Bullen (1982), that the number of ’at least moderately affected’ or ’seriously affected’ residents will be zero in the local government area of Ku-ring-gai. This local government area of approximately 106,000 residents is located at least 15 and as much as 30 kilometres north of Sydney airport and is primarily exposed to aircraft landing from the north. This paper reports on the major findings of a questionnaire survey, carried out in September 1995, involving a sample of 5000 randomly selected voters of Ku-ring-gai and using a questionnaire which is essentially identical to that used by Hede and Bullen (1982). The results show that the DNMP underestimated the number of aircraft noise affected people by at least 13 per cent on the basis of the local government area of Ku-ring-gai alone.

313 Click here to view scanned manuscript ICSV5 Paper Abstract Effects of Traffic Noise Within the Madrid Region Authors: Manuel Recuero, Universidad Politecnica de Madrid, ( Spain) C. Gil, Universidad Politecnica de Madrid, ( Spain) J. Grundman, Universidad Politecnica de Madrid, ( Spain) Volume 5, page 2593, paper no. 531 Abstract: In this work the results of a 20-question survey about the acoustic environment made on the population of 17 towns are presented. Up to 7141 questionnaires were distributed, where 3272 were conducted in population centers with more than 100000 inhabitants, 2695 in towns below 100000 and above 50000 inhabitants and 1174 in towns with less than 50000 inhabitants. The aim of this statistical work is to estimate the citizens’ opinion about noise sources in their municipalities, the annoyance that these sources produce, where and when the effect seems stronger and how the noise affects residential areas. There were also questions concerning the opinion about protection against noise in dwellings and the presumed effects of environmental noise. Finally, it was intended to know how important the residents think the environmental noise problem is, how deep is their knowledge about their rights and the law and what do they think about possible measures to improve the situation.

314 Click here to view scanned manuscript ICSV5 Paper Abstract Heavy Vehicle Noise Reduction Strategy Authors: Peter Karantonis, Renzo Tonin & Associates Pty Ltd, ( Australia) Najah Ishac, Renzo Tonin & Associates Pty Ltd, ( Australia) Renzo Tonin, Renzo Tonin & Associates Pty Ltd, ( Australia) Volume 5, page 2601, paper no. 511 Abstract: Concern has been shown over the misuse of engine compression brakes in urban areas. This Is of particular Interest when heavy vehicles have defective, missing or non-approved mufflers fitted. While operators of heavy vehicles fitted with such auxiliary brakes state that they are used for safety reasons, previous studies suggest the use of supplementary brakes is purely to lower costs (ie reduce brake lining wear). The overall primary objectives of the research conducted by Renzo Tonin & Associates Pty Ltd were to: evaluate the relationship between brake lining temperatures and compare temperatures to manufacturer safety limits; evaluate the relationship between service brake wear and engine compression brake usage; address the anecdotal evidence concerning adverse fuel consumption associated with standard versus after-market mufflers; Investigate engine compression brake noise levels associated with standard versus after-market mufflers.

315 Click here to view scanned manuscript ICSV5 Paper Abstract Modeling of Urban Traffic Noise Authors: Momir Prascevic, University of Nis, ( Yugoslavia) Dragan S. Cvetkovic, University of Nis, ( Yugoslavia) A.S. Deljanin, JP PTT, ( Yugoslavia) V.O. Stojanovic, Advanced Technical School, ( Yugoslavia) Volume 5, page 2609, paper no. 485 Abstract: The traffic noise, as main source in urban areas, makes up part of general environment problem which inflicts serious damage to the health of human beings and lowers their labor productivity. With little or no noise abatement legislation and by disregarding eventual noise control measures in sound source themselves and in urban environments, the traffic noise in cities may grow up alarmingly due to continued development of transportation infrastructure, to higher unit capacities and speeds of motor vehicles. Therefore, the control of traffic noise has become a matter of major concern for communities trying to maintain a satisfactory environment in which to live and work. In order to modeling traffic noise and selecting corresponding noise controi measures it is necessary to know functional relationships between noise emission and certain numbers of traffic parameters. The noise levels can be predicted by a mathematical model while designing planning and developments schemes for new transportation routes and re-development of existing ones or when the flow and composition of traffic are changed, in this paper, the results of modeling road traffic noise level by trending of the experimental data collected by systematic noise measurement at 11 measurement points in urban areas of Nis will be shown,

316 Click here to view scanned manuscript ICSV5 Paper Abstract A Proposed Compression Brake Noise Test Procedure Authors: Thomas E. Reinhart, Cummins Engine Company, ( U.S.A.) Thomas J. Wahl, Cummins Engine Company, ( U.S.A.) Volume 5, page 2615, paper no. 404 Abstract: Compression brakes are typically installed on heavy trucks, and operated when the truck is going down- hill, although drivers sometimes use them on level ground. The noise generated by compression brakes can be a source of excessive traﬃc noise. A test procedure is required in order to understand compression brake noise, develop improvements, and form the basis for regulation of brake noise. The challenge in developing a brake noise test procedure is to design a test which is simple and repeatable, while accurately simulating the noise generated under normal operating conditions. The test method proposed here is based on the standard ISO 362 acceleration driveby test. In the new procedure, an unladen truck enters the test track at high idle (maximum achievable engine speed), and decelerates past the microphones with the compression brake on. Extensive test results demonstrate that a relatively low speed test with an unladen truck provides a valid simulation for the brake noise of a fully laden truck going down a hill. The repeatability of the proposed test is also demonstrated, along with the sensitivity of the results to changes in test parameters.

317 Click here to view scanned manuscript ICSV5 Paper Abstract Effectiveness of Insulation Program for Houses Around Sydney Airport Authors: Marion Burgess, Australian Defence Force Academy, ( Australia) Volume 5, page 2623, paper no. 397 Abstract: The Residential Insulation Scheme is an important part of the Sydney Airport Noise Amelioration Project. This scheme is based on the application of treatments from a Menu based on the external aircraft noise. Following implementation in over 400 houses the acoustic data obtained from measurements in a sample of 61 houses before and after treatment have been analysed. The aim of the analysis was to assess the effectiveness of the insulation scheme and in particular to ascertain if improvements or changes were necessary. For the majority of the sample, the aircraft noise attenuation achieved for the bedrooms was as would be expected. The reasons for lower than expected attenuation were identified for the others. Two important finding from the study were that kitchens and living rooms are likely to achieve lower attenuation than bedrooms and that attention to detail in the inspection process is essential. It was also found that while the use of the Menu appears to be an effective and fair means for choosing the appropriate measures, there is some scope for simplification.

318 Click here to view scanned manuscript ICSV5 Paper Abstract Modelling In-Vehicle Engine Noise (Listen to the Noise Paths) Authors: Patrick Van de Ponseele, LMS International, ( Belgium) S. Campino, Universite de Technologie de Compiegne, ( France) Filip Deblauwe, LMS International, ( Belgium) Geert Lowet, LMS International, ( Belgium) Volume 5, page 2629, paper no. 387 Abstract: Too often car manufacturers are confronted with noises inside the passenger compartment. The solution to such a problem has quite often been one from try and see. However, in the last five years new tools, such as transfer path analysis, have been developed. These tools have been a great help in understanding the contribution of the different components, such as engine, exhaust etc., to the total interior noise. The new techniques also provide the capability of modifying the path of the different components and estimate anew spectrum of the interior noise of the car. However in all these new powerful and useful tools there is still one missing link. It is very hard to judge the impact of the modifications on the sound perception solely based on a spectrum. One can only judge the modifications to its full extend when one can listen to the modification. This paper describes how transfer path analysis has been integrated and the modification of low engine orders in a sound quality package to provide the possibility to evaluate the modifications from a sound quality standpoint. The main challenge for this problem is to only modify the components in the original signal that are influenced by the transfer path analysis without losing the other components that guarantee the background color of the sound.

319 Click here to view scanned manuscript ICSV5 Paper Abstract Numerical Study on the Radiation of Intake Noise from Internal Combustion Engine by Using Essentially Non- Oscillatory Schemes Authors: Yong Seok Kim, Korea Advanced Institute of Science and Technology, ( Korea) Duck Joo Lee, Korea Advanced Institute of Science and Technology, ( Korea) Volume 5, page 2635, paper no. 332 Abstract: Traditionally, intake noise from internal combustion engine has not received nearly as much attention as exhaust noise. But nowadays, intake noise is a major contributing factor to automotive passenger compartment noise levels. In this study, compressible Navier-Stokes eqns are employed numerically for the intake stroke of axisymmetric model having a single cylinder and a single intake valve. The main objective of this paper is to identify the mechanism of generation, propagation and radiation of the intake noise. The main noise source for the intake stroke was found to be the pressure surge which is generated after intake valve closing. The pressure surge which has the nonlinear acoustic behavior propagates and radiates with small attenuation. To simulate the periodic motion of the piston and valve, unsteady deforming mesh algorithm is employed and Thompson’s non-reflecting boundary condition is applied to the radiation field. In order to resolve the small amplitude waves and the radiation field, essentially

320 Click here to view scanned manuscript ICSV5 Paper Abstract Characteristics of Compression Brake Noise Authors: Thomas E. Reinhart, Cummins Engine Company, ( U.S.A.) Thomas J. Wahl, Cummins Engine Company, ( U.S.A.) Volume 5, page 2643, paper no. 201 Abstract: This study examines compression brake noise levels in heavy-duty diesel trucks, using test procedures based on the ISO and EPA driveby acceleration noise tests. The data shows that compression brake noise levels are very high if worn out or open stack exhaust systems are used. Compression brake noise is also audible with OEM exhaust systems and, in at least one case, potentially objectionable. This study also describes the time and frequency domain characteristics of compression brake noise. Brake noise is dominated by strong pressure impulses which repeat at one of the first three harmonics of engine firing frequency. The subjective quality of brake noise is primarily determined by medium and high frequency noise which is produced by the periodic pulses. No useful correlation between brake performance parameters and noise levels is found. Two methods for reducing brake noise are investigated: improved mufflers and the use of an exhaust brake with the compression brake. Both techniques demonstrate a potential for reducing compression brake noise, but an improved muffler is far more cost effective.

321 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Generated by Underground Railway Trains Authors: Hugh E.M. Hunt Jonathan E. May Volume 5, page 2653, paper no. 525 Abstract: The control of vibration generated by railways in tunnels is complicated by the dynamic interaction between tunnel and track. Conventional methods (floating slab track, ballast mats, under-sleeper pads) do not perform as well as might be expected and it is the purpose of this paper to explore the sources of error. The major factors which must be taken into account pertain to the three-dimensional vibration modes of the tunnel and their interaction with the track and with the surrounding soil. These factors are usually omitted under existing design methodologies and supposed improvements in track design are often not effective. The model used to quantify tunnel effects is based on exact solutions to the 3- dimensional wave equation as applied to a tunnel of infinite length. For a typical tunnel there are many resonance frequencies to be found in the range from 5 to 100Hz, most significant for railway vibration calculations.

322 Click here to view scanned manuscript ICSV5 Paper Abstract Optimization of Noise and Vibration Protection Approaches in Movable Compressors Authors: Lyudmila Ph. Drozdova, Baltic State Technical University, ( Russia) Nikolay I. Ivanov, Baltic State Technical University, ( Russia) Alexander V. Omelchenko, Baltic State Technical University, ( Russia) Vyacheslav V. Potekhin, Baltic State Technical University, ( Russia) Volume 5, page 2661, paper no. 465 Abstract: The reduction of noise of movable compressors (MC) is a problem of great importance in Russia. Today most leading foreign compressor-manufacturing firms produce MC in sound-proofed varieties. Differ- ent methods can be used for the noise and vibration reduction of compressors depending on their types, such as: installation of sounf-proofed enclosures, mufflers, sound buffles, sound-absorbing and vibration-damping constructions, etc. Each approach when used separately or together with the others can provide a reduction in the noise to the noise limit. Therefore the designer always faces the problem of choosing the optimum approach. In this paper authors solved the problem of optimization of the noise and vibration protection approaches by choosing the noise reduction procedures using the cost and efficiency criteria for a given noise limit at a specified point.

323 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Isolation Performance of Floating Slab Track Used in Underground Railways Authors: James A. Forrest Volume 5, page 2665, paper no. 526 Abstract: Floating slab track is a popular approach used to try to reduce vibration transmitted from underground railways into the surrounding soil and thence into nearby buildings. The rails are fixed to a concrete slab foundation which is supported on a resilient mounting, so isolating the track from the tunnel invert. However, the effectiveness of the vibration attenuation does not compare well with the simple mass- spring models typically used in the design of these tracks. This paper uses models of infinite length to investigate the performance of floating slab track in more detail. A track model constructed from an infinite series of repeating units is presented, each unit being two beams (for the rail and the slab) separated by elastic layers (for the resilient elements used in the track construction). An improved model consisting of an infinite slab beam mounted inside a tunnel of infinite length in soil of infinite extent is also presented.

324 Click here to view scanned manuscript ICSV5 Paper Abstract Models for an Elevator Hoistway Vertical Dynamic Sys- tem Authors: Yue Qi Zhou, Nippon Otis Elevator Company, ( Japan) Volume 5, page 2673, paper no. 398 Abstract: Many proposals have been made in recent years for building skyscrapers with heights in excess of 300 meters. For elevators in high buildings, the torque ripples generated by the traction motors can cause the cars to oscillate vertically due to the existence of the long ropes from which the elevator car hangs. In this study, a simpliﬁed 8-degrees-of-freedom model, which assumes the ropes to be spring and dashpot elements by neglecting the rope mass, is created for an elevator hoistway vertical dynamic system. The solutions are obtained by solving the 8 linear diﬀerential equations using MATLAB. In addition, an FEA model using computer code of ANSYS is also created for studying the dynamic behaviors of the long ropes. The results from those two models are compared and discussed, which gives the conclusion that it is necessary to use the FEA model for the analysis of elevator hoistway vertical dynamic system for high buildings.

325 Click here to view scanned manuscript ICSV5 Paper Abstract Prediction of Ground Vibration Induced by High-Speed Train Operation Authors: Hirokazu Takemiya, Okayama University, ( Japan) Kazuya Goda, Toyo Construction Co. Ltd., ( Japan) Volume 5, page 2681, paper no. 354 Abstract: Connecting cities by high speed trains is pursued in view of the increasing mass transportation of people and cargo. Speeding up of the train operation on track may produce some unexpected environmental problems like vibrations to propagate toward the neighborhood, disturbing people and giving trouble to sensitive machines along the track. The prediction and the countermeasure of vibrations by such moving source is of essential interest. In this paper, theoretical approach is first made for the induced wave propagation by a moving oscillatory load on layered soil, The three-dimensional analysis is conducted by taking Fourier transform of the governing equation with respect to time and space coordinates along the moving direction and the perpendicular to it. The solution satisfying the given boundary condition is obtained in the transformed domain. Since the concerned phenomenon does not require the causality, the back transformation from frequency-wave number to time-space coordinates along the moving direction is carried out analytically. The back transformation in the remaining coordinates is resorted to the discrete wave number method with application of the FFT algorithm. In order to disclose the fundamentals in wave field in the layered soil in the above situation, the dispersion curve e is obtained and interpreted, focusing on the Airy phase for predicting the dominant wave propagation. The embankment track on layered soil is then analyzed. The Green function for a layered soil is developed for certain distributed load in order to avoid the involvement of the singularity otherwise, The interaction of the embankment and the underlain soil is treated by the hybrid method by BEM and FEM. The field measurements are conducted on ground vibrations along the Shinkansen track and in nearby locations. This enables us to do an inverse analysis for predicting the train induced vibrations near the track. Results from the present study are summarized as follows: 1. The speed of the train operation is important when it approaches the Rayleigh wave of the soil. The transient vibration due to the train passage generates not only the Doppler effect but also the layer vibration, 2. The dynamic characteristics of the embankment and the interaction between the embankment and the underlain soil are important for the vibration assessment in train operation. 3. The inverse analysis was executed for the vibration prediction near the Shinkan-sen track to determine the parameters involved appropriately,

326 Click here to view scanned manuscript ICSV5 Paper Abstract Random Vibration of Engine-Mounting System with Motion- Limiting Stops Authors: Masaharu Aisaka, ISUZU Motors Limited, ( Japan) Isao Yokomichi, Kitakyushu College of Technology, ( Japan) Yoshiaki Araki, Kyushu Institute of Technology, ( Japan) Takeshi Inoh, ISUZU Motors Limited, ( Japan) Volume 5, page 2689, paper no. 267 Abstract: This paper presents some results of a theoretical study of random impact vibrations of the engine- mounting system of heavy-duty trucks. The dynamic model of a vehicle is reduced to five degree-of- freedom system equipped with stoppers to limit the engine-body movement when traveling on rough roads. The impact force is reduced to the linear restoring and damping forces using by statistically equivalent coefficients of stiffness and damping. The responses of the system to road surface undula- tions are determined from the moment equation. These theoretical results are confirmed by the digital simulation.

327 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Variability and Sonar Authors: Adrian D. Jones, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2701, paper no. 392 Abstract: The performance of sonar systems, particularly in shallow ocean areas typical of a continental shelf, is complicated and limited by the variability of the acoustic signals which are received. Here, signals vary over time, with spatial location and with frequency, often in ways that are poorly understood. The present state of knowledge of this acoustic variability is reviewed, and some recent developments which have de-mystified some aspects of the phenomena are described. As is shown, average descriptions of the variation of signals with frequency, position and time may be determined, based on the properties of the acoustic signal field. It is shown how these descriptions suggest that the performance of sonar systems may be optimised. It is also shown how these descriptions lead to the specification of parameters for system performance and effectiveness modelling.

328 Click here to view scanned manuscript ICSV5 Paper Abstract Prediction of Line-Spectrum Noise Induced by Under- water Vehicle Contra-Rotating Propellers Authors: Xiqing Zhu, China Ship Scientific Research Center, ( China) Wusheng Wu, China Ship Scientific Research Center, ( China) Volume 5, page 2721, paper no. 255 Abstract: Line-Spectrum noise of counter-rotation propellers has constructed the main part of the radiated noise of underwater vehicles. The line-spectrum noise of the counter-rotation propellers is due to the interaction between fore or aft propeller and wake of the vehicle, and the interaction between fore and aft propeller, Based on a combination of the lifting surface theory and acoustic thecniques, the prediction method of line-spectrum noise is presented in this paper, Theoretical calculation method, characteristics and numerical prediction of the line-spectrum noise are detailed in this paper. The effect of different wake and different distance between fore and aft propeller on the propeller noise is also studied by numerical method, The agreement of predicted results compared with existing experimental data is quite satisfactory. Therefore, the methods are to have important values for performance prediction of the vehicles, inspection of the noise sources and acoustic design of counter-rotation propellers ,etc,

329 Click here to view scanned manuscript ICSV5 Paper Abstract Optimal Pulse Shaping in Reverberation - Limited Envi- ronments Authors: Henry Lew, Defence Science and Technology Organisation, ( Australia) R.F. Barrett, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2729, paper no. 475 Abstract: In active sensing systems, such as radar and sonar, the transmitted waveform has an important inﬂu- ence on target detection (especially in reverberation limited environments), parameter estimation and the resolution capability of the system. A method of generating waveforms which maximizes the output signal-to-noise (ambient plus interference) ratio of a replica correlator receiver is given. These waveforms are optimal only for a particular realization of the noise. A large set of such waveforms can be generated by Monte Carlo simulation. From this set, the robust optimum waveform, i.e., the one least sensitive to diﬀerent noise realizations, can be determined.

330 Click here to view scanned manuscript ICSV5 Paper Abstract Trapped Modes In Elastic Constructionbs Lying in the bottom of a Channel of Non-Compressible Weight Liq- uid Authors: Dmitri Indeitsev, Institute for Problems in Mechanical Engineering, ( Russia) V. Alekseev, Institute for Problems in Mechanical Engineering, ( Russia) Yu Mochalova, Institute for Problems in Mechanical Engineering, ( Russia) Volume 5, page 2739, paper no. 447 Abstract: The phenomenon of trapped modes (standing waves) near the underwa-ter constructions has been studied. The influence of construction dynamic on the process of trapped modes formation has been studied. It has been also shown that existence and a number of resonance frequencies essentially depend on elastic construction and channel parameters. The influence of liq-uid nonhomogenity on the initiation of trapped modes has been investigated separately. It is shown that only for specific gradient of liquid density the phenomenon of trapped modes can exist.

331 Click here to view scanned manuscript ICSV5 Paper Abstract Transmission Loss: Comparisons Between Experimen- tal Data and Normal Mode Predictions Based on a Seafloor Lithology Database Authors: Ashley Ian Larsson, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2747, paper no. 353 Abstract: The prediction of underwater acoustics is important to show the capabilities of a theoretical sonar system and improving sonar systems. Unfortunately under water acoustics is complicated and awkward to model - especially the sea floor acoustics. Often many assumptions are made in order to model the acoustics of the sea floor. Most under water models are covered under four categories, which are Nor- mal mode theory, Ray theory, Parabolic equation and Fast field transform methods, but all require input of ocean floor acoustic properties. Those properties themselves are often poorly known and need to be estimated from geological data. There are several models which link seafloor geological parameters to acoustic properties - for example Hamilton(l) and Biot(2). For the Australian region the AUSEABED database Jenkins (3) provides data on the Iithology and other geophysical properties of the seafloor, from which acoustic parameters may be estimated Jenkins(4), Using this resource and a Normal mode model, transmission loss was calculated and compared with in

332 Click here to view scanned manuscript ICSV5 Paper Abstract Initial Shallow Water Bottom Loss Measurements in the Timor Sea Authors: Graham D Furnell, Defence Science and Technology Organisation, ( Australia) Graham J. Day, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2755, paper no. 338 Abstract: The acoustical features of the shallow water environment can have a harsh effect on the performance of sonar systems. By no means the least important of these features are low grazing angle values of bottom reflection loss, which can largely determine transmission loss encountered. This paper presents the initial results of measurements of low grazing angle bottom loss conducted in the shallow waters of the Timor Seato the north of Australia. The measurements were performed over the frequency band 0.5-4 kHz via a technique which exploits the interference field created by the interaction between direct path and bottom reflected sound.

333 Click here to view scanned manuscript ICSV5 Paper Abstract The Effectiveness of Sparse Random Arrays For Under- water Acoustic Imaging Authors: David G. Blair, Defence Science and Technology Organisation, ( Australia) Jim Thompson, Defence Science and Technology Organisation, ( Australia) Stuart Anstee, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2765, paper no. 333 Abstract: It is intended to produce an underwater acoustic imaging system with three-dimensional images of resolution around 1 mm at 1 m range. For this purpose, sparse random arrays have considerable cost and feasibility advantages over filled arrays. There is no degradation of beamwidth, while the average dis- tant sidelobe level (ADSL) can be reduced to a level expected to be satisfactory for imaging surfaces such as sea mines, although unsatisfactory for imaging continua such as human tissue. We have simulated the imaging of point targets by random arrays of elements. The simulation uses exact path lengths in the near field. Good range resolution is obtained through either a short toneburst or a cross-correlated chirped signal. It is confirmed that, as the array is made more sparse, the ADSL rises. For broadband signals, the ADSL is found to be markedly lower than the monofrequency value. The use of partially random arrays, constructed out of identical subarrays for ease of manufacture but oriented randomly, leads to an appreciable degradation in ADSL. For example, a system of 100 square subarrays with four subarray orientations resulted in an ADSL penalty of 5 dB.

334 Click here to view scanned manuscript ICSV5 Paper Abstract Acoustic Seabed Models Obtained by Inverting Explo- sive Shallow Water Transmission Loss Data Authors: Marshall V. Hall, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2773, paper no. 328 Abstract: Acoustic transmission losses (TL) measured at 16 Hz along a track in shallow water have been inverted to obtain seabed acoustic properties. The data are represented by an analytic function of range with two free parameters. The seabed is modelled as an equivalent uniform half-space. A uniform space has 5 unknowns: sound and shear speeds, sound and shear absorption coefficients, and density. The number of unknowns is reduced to three by using regression equations to relate density and shear absorption to sound-speed. By holding shear-speed fixed for subsets of the process, the number of unknowns is reduced to two (sound-speed and absorption). The parameters of the TL analytic function are computed over intervals of these unknowns by fitting outputs of the "Oases" mathematical model, and solutions of the resulting pair of simultaneous equations are sought. Finally, these solutions are expressed as functions of shear-speed, and criteria are presented for selecting the optimum results. The equivalent half-space is not necessarily related to the actual properties of the seabed and is liable to vary with frequency. It should however, produce correct results when an appropriate TL model is run at the original frequency, for arbitrary source and receiver depths and water-column conditions.

335 Click here to view scanned manuscript ICSV5 Paper Abstract Propagation of a Low-frequency Sound in a Hydroa- coustic Waveguide with the Thin Ice-floe of Finite Width Laying on a Surface Authors: Sergey M. Grudskii, Rostov State University, ( Russia) S.S. Mikhalkovich, Rostov State University, ( Russia) Volume 5, page 2781, paper no. 262 Abstract: The paper is devoted to the problem of sound propagation in stratified waveguide which is a non– homogeneous liquid layer overlaying multi-layered liquid-elastic bottom with the thin ise–floe of finite width laying on a surface. Influence of the ice–floe to characteristics of an acoustic field is investigated. For the problem solution the ice layer is replaced by equivalent in some sense condition on a surface of "defreesed ice". Problem with this condition can be easily reduced to the equation of convolution on a finite interval or, in Fourier images, to so-called modified Wiener–Hopf equation. To solve this equation we use a method of matrix Riemann boundary problem. It allows to construct asymptotic formulas for elements of reflection and transmission matrices by a small parameter, characterizing thickness of ice. These formulas are uniform on ice-floe width. Finally some numerical calculations are given to obtain quantitative estimates for so-called "critical" ice-floe lengths and to illustrate influence of absorption in ice on attenuation of acoustic field.

336 Click here to view scanned manuscript ICSV5 Paper Abstract Shallow Water Propagation Modelling from 5HZ to 25KHZ Authors: David N. Matthews, Defence Science and Technology Organisation, ( Australia) Marshall V. Hall, Defence Science and Technology Organisation, ( Australia) B.L. Jessup, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2789, paper no. 141 Abstract: To accurately predict sound propagation in shallow water (12-60m) over a wide frequency band (5Hz-25 Khz) and at ranges up to 2000 m using a single acoustic propagation model is a difficult task. Probably the only model that claims to come near to fulfilling this requirement is OASES[1] although the maximum range achieved drops to only 100 m at the higher frequencies. There are however a number of other models available, each of which has a "domain of applicability". This paper compares two of these models, a ray model (ISO-RAY)[2] and a normal mode model (STOKES) [3] , and assesses their useability over the frequency range stated above. In addition it also investigates the operational limitations of OAST (the transmission loss module of OASES), since this model is generally considered a benchmark in underwater acoustics. By combining the ray and normal mode model it was possible to nearly fulfil the above requirement .

337 Click here to view scanned manuscript ICSV5 Paper Abstract Cross Correlation of Directional Sonobuoys Authors: Edwin R. Galbreath, Defence Science and Technology Organisation, ( Australia) Ross L. Dawe, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2797, paper no. 56 Abstract: This paper describes a method to extend the effective detection range of a pair of directional sonar arrays such as sonobuoys by cross correlating beamformed time series data. This technique effectively treats the sonobuoys as a field instead of independent sensors and gives a theoretical improvement in system detection threshold of 5log10(n)dB, where n is the number of sonobuoys. The time series output from the sonobuoy beams are compared and the resulting modulus of the normalised cross correlation coefficient is plotted on a map display overlaid with the buoy positions. Results using both simulated and experimental data indicate the technique can be successful in assisting the observer to detect and localise weak acoustic targets.

338 Click here to view scanned manuscript ICSV5 Paper Abstract Attenuation of Acoustic Waves by a Thin Cylindrical Bubbly Layer Authors: Patrick Yeung, The University of Hong Kong, ( Hong Kong) Allen T. Chwang, The University of Hong Kong, ( Hong Kong) Volume 5, page 2805, paper no. 21 Abstract: Using a bubbly liquid is an economical and effective technique in controlling underwater sound signals. The sound speed in a bubbly liquid can be much different from that in a pure liquid and it has a very strong dispersive effect. When a sound signal passes through a bubbly layer, some of the energy is reflected and some is lost due to dissipation. Thus, the signal is attenuated. This property can be used to control underwater noise emitted from a submarine or an underwater construction site.In this paper, in order to apply this technique to real engineering problems, a harmonic point source enclosed by a cylindrical bubbly layer is considered. Due to the randomness and nonlinear behaviour of the mixture, rigorous models are hard to be developed. However, by assuming that bubbles are small in spherical shape and there is no interaction between the bubbles, classical theory for dilute bubbly liquid can be employed. Applying Taylors expansion and numerical integration, transmitted pressure fields through a thin cylindrical bubbly layer are obtained in an infinite domain, near a free surface, near a flat seafloor and in water with finite depth. It is found that if the bubbly liquid obeys the theory, the transmissim is very low when the incident frequency is higher than the natural frequency of the bubbles. This is called the Dead Zone of the bubbly liquid. There will be no propagating mode for an acoustic wave when it passes through the "Dead Zone.In addition, experimental results of a cylindrical bubbly layer with air volume fraction about 10% are obtained and compared with the theoretical results, lt is found that the experimental results agree with the theory if the incident frequency is near the bubble natural frequency. However, when the incident frequency is further increased there is a significant difference between experiment and theory. The transmission coefficient obtained in the experiment is much higher than that predicted by the dilute bubbly liquid theory. This seems that the Dead Zone does not appear in the experiments. The classical theory cannot be applied to this finite air volume fraction bubbly liquid. Discussion is given for the explanation of the phenomena and the design of bubbly layer on underwater sound control.

339 Click here to view scanned manuscript ICSV5 Paper Abstract Ambient Sea Noise in Australian Waters Authors: Douglas H Cato, Defence Science and Technology Organisation, ( Australia) Volume 5, page 2813, paper no. 15 Abstract: The wide range of oceanic conditions around Australia result in wide variation in the characteristics and the levels of ambient sea noise, showing significant differences to observations of noise in the northern hemisphere. Contributions from independently varying sources result in variations in noise level of more than 30 dB with variations of up to 20 dB occurring commonly. Spectral shapes vary widely depending on the dominant sources at the time. Because of low levels of traffic noise in many areas, sea surface generated noise is often dominant at low frequencies (below about 200 Hz) in contrast to most northern hemisphere observations. Biological noise is usually dominant in tropical waters, except for conditions of high winds or heavy rain. Biological choruses that result when countless fish or invertebrates are calling are widespread in tropical and temperate waters, some showing regular diurnal variation. These choruses are often rise more than 20 dB above the background noise, Intense transient signals from whales also make significant contributions to the ambient noise.

340 Click here to view scanned manuscript ICSV5 Paper Abstract Experimental Investigation of the Influence of Magnetic Field on the Cavitation Inception in Pulse Rarefaction Waves in Water Authors: Alexey S. Besov, Lavrentyev Institute of Hydrodynamics, ( Russia) Volume 5, page 2819, paper no. 283 Abstract: The influence of magnetic field on the cavitation processes in pulse rarefaction waves in water is investigated experimentaly. It is shown, that water is transformed into anew state. This state is characterized by a temporary increasing of the threshold of cavitation inception and the significant influence of magnetic field on the dynamics of a bubbly cluster. The life time of new state of water is found to depend on the intensity of loading. The mechanism of the influence of a magnetic field on the cavitation ability of water is proposed. It is based on the change of pfysical properties of cavitation nuclei under pulse loading at magnetic field presence. The possible influence of hysteresis properties of water [2] is excluded by preliminary loading the water samples with the chosen amplitude shock wave. A rarefaction wave is produced by reflecting a plane short (a few microseconds) shock wave from the free surface of water [1]. For the detection of the threshold of cavitation inception and dynamics of bubbly cluster the variable capacitance transducer method [1] is used.

341 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Thermodynamics of Vibrations Induced by Continuous Light in Liquids Authors: Anatoly T. Sukhodolsky, General Physics Institute, ( Russia) Volume 5, page 2829, paper no. 524 Abstract: Any amount of mechanical energy is known to be transformed into heat without any restriction. The principle of Carnot is to restrict any creation of mechanical energy from heat in heat engines on basis of entropy concept. The aim of this paper is to give an introduction to thermodynamics of the natural processes when eﬀective generation of mechanical energy takes place without any devices owing to self-organization of a heat cycle. The main topics to discuss are: an advanced interpretation of Carnot principle and non-equilibrium entropy of light, the theorem of Carnot and maximum thermal eciency available for generation of vibrations.

342 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Digital Control Discrete Models of Active Vibration Iso- lation Authors: Larisa A. Rybak, Russian Academy of Sciences, ( Russia) Volume 5, page 2839, paper no. 564 Abstract: Application of vibration isolation systems with kinematic operation principle is a perspective trend in the development of protection systems against basement vibrations impact . Connections of the object with its basement represent stiff/rigid mechanisms wich concrol relative position of the object and of its basement with help of information obtained from sensors of relative position of the object, its basement and accelerometers too, that are installed both at the object and on its basement. In case of basement motion absence, similar systems are insensitive to dynamic forces applied to the object, and only basement motion excitation sets the object in a relative motion with help of accelerometers. The vibration isolation problem could be achived by the creation of digital control methods of drive actuation. Here two approaches could be used. The first one is based on invariant control principle. We can create such a mode when we compensate acceleration on the object in such a way that it coues to zero due to the processing of accelerometer sygnal placed on the basement. The second way cousists of traditioual methods to produce lower frequency filter. A third idea is to combine in a certain way these two approaches.

343 Click here to view scanned manuscript ICSV5 Paper Abstract The Yo-Yo as a Structural Vibration Exciter - Force Time Histories Authors: Leonard L Koss, Monash University, ( Australia) Volume 5, page 2845, paper no. 111 Abstract: The mechanical action of a Yo Yo has several attributes which may give the toy a useful function as a vibration exciter for structures which have relatively low natural frequencies such as bridges and towers. The first attribute is that when a Yo Yo is released from a structure, the structure is exposed to a step input due to the loss of mass of the Yo Yo. The second attribute is that of an almost impulsive force input to the structure when the body of the Yo Yo reaches the bottom of its stroke due to the change in linear momentum over a short period of time. The third attribute is associated with the return of the Yo Yo body to its starting point if certain conditions on initial angular momentum, damping and string length are satisfied.Both a theoretical study and practical measurement have been undertaken to demonstrate the above attributes. Thus, in a cycle of Yo Yo motion the structure attached to the string of the Yo Yo is excited twice into vibration, the impulsive excitation being the greater source of vibration generation.The matrix equations of motion of a Yo Yo attached to a simple are spring mass systemwhere ml is the mass of the structure, m2is the linear mass of the Yo Yo, r is the radius of the Yo Yo spindle, I is the moment of inertia of the Yo Yo body, g is the gravitational constant, k is the structural stiffness, c1is structures viscous damping coefficient, c2 is the Yo Yo viscous damping coefficient and xl and X2are the coordinates which specify the position of the structure and Yo Yo, respectively. These equations are solved simultaneously using the Matlab computer code. A typical simulation result is shown below. Results and comparisons of theory and experiment will be given in the paper.

344 Click here to view scanned manuscript ICSV5 Paper Abstract Factorization Method in Annular Plates Vibrations Authors: Dumitru Caruntu, University of Bucharest, ( Romania) Volume 5, page 2855, paper no. 550 Abstract: The annular plates are used in many structural applications. Therefore, the analysis of the annular plates’ vibrations is of interest to many mechanical, aeronautical and civil engineers. We base our considerations on the classical plates’ theory. The paper involves factoring the fourth-order linear diﬀerential operator, which appears in the equation of motion, into a pair of second order operators. For the annular plates with variable thickness, the conditions in which factorization is possible are presented. In this way, all the annular plates whose thickness varies with the radius for which this method is applicable are found. For example, the paper determines the general solution of vibrations diﬀerential equation and solves the eigenfrequencies’ problem of annular plates with parabolic thickness.

345 Click here to view scanned manuscript ICSV5 Paper Abstract An Experimental Investigation into Torsional Vibration in Ball Mills Authors: R.M. Heidecker, University of Western Australia, ( Australia) S.J. Drew, University of Western Australia, ( Australia) Brian J. Stone, University of Western Australia, ( Australia) Volume 5, page 2863, paper no. 549 Abstract: Torsional vibration in ball mills can be a serious problem - even leading to failure. In the design of such mills it is therefore important to be able to design them so that such vibration will not be a problem. It is thus desirable to be able to model the torsional vibration of a rotating system which includes a ball mill. The major difficulty with modelling torsional vibration is the low level of damping in rotating systems and insufficient information about its magnitude. This paper describes an experimental investigation of the torsional vibration of a ball mill with a particular emphasis on the damping of the mill itself. It was considered possible that the mill could be a significant source of energy dissipation for torsional vibration. A small batch ball mill was investigated using a servo motor as both the drive and a torsional exciter. The main parameters of the rig were varied and a systematic series of tests was performed for each combination of parameters. The inertia and damping of the mill were studied and the results are presented.

346 Click here to view scanned manuscript ICSV5 Paper Abstract Discovering the Rectilinear Model of Complex Torsional Vibratory Systems With the Aid of Bond Graphs Authors: Kazem Abhary, University of South Australia, ( Australia) Volume 5, page 2871, paper no. 546 Abstract: Unlike complex lumped parameter rectilinear vibratory systems which can be easily and exactly formulated and then solved by widely available commercial computer packages, the solution of complex lumped parameter torsional vibratory systems is lengthy and time consuming. These systems can be solved by either the Holzer’s method or the Transfer Matrix method. The former is unable to handle damped systems and the application of the latter upon damped systems is cumbersome. Both methods are numerical and the solution time dramatically increases by the increase in the number of branches of the torsional system, such that the inclusion of even an example of a four-branch system in mechanical vibrations textbooks has become prohibitive, let alone a complex multi-branch torsional system. In this paper, bond graphs have been used as a medium to facilitate the rectilinear modelling of complex torsional systems. It has been demonstrated that through elimination of the transformers, the bond graph of a torsional system will be converted to the bond graph of a rectilinear system on the basis of which the rectilinear model of the torsional system can be established. The model has been proven to follow a simple pattern and to be very rapidly constructible, irrespective of the complexity of the system. This approach has converted the project-type problems (via the Holzer’s and Transfer Matrix methods) to simple class-room tutorials.

347 Click here to view scanned manuscript ICSV5 Paper Abstract Some Aspects of Interfacial Motion Relevant to Forced Oscillations Authors: Sead Spuzic, King Fahd University of Petroleum and Minerals, ( Saudi Arabia) Ian Reid, University of South Australia, ( Australia) Milorad Zec, Norwegian University of Science and Technology, ( Norway) Volume 5, page 2879, paper no. 535 Abstract: Mechanisms comprising oscillating components have important engineering applications. These systems are often based on forced oscillatory motion of vital elements. Solid surfaces, involved in dynamic contact, almost always experience sliding and wear along the active interface. This effect becomes ex- tremely significant in mechanisms designed to perform multiple automatic motions. The recursive motion, intended to follow a precise kinematic pattern, ultimately shows adverse deviations. Engineering technologies developed to combat these deviations, e.g. the hardfacing, need the appropriate criteria to evaluate the maintenance economy. In addition to geometric degradation, the disadvantageous vibrations occur as the result of growing dissipative forces. The number of material attributes, e.g. the elastic moduli, can significantly change with the sliding distance. Presently, the theory of kinematics does not provide complete models for sliding distance for rolling-sliding contact. Currently, the fundamental concepts of circular motion and oscillations are presented without addressing this important aspect of the motion gradient with respect to contacting surfaces. This paper presents the mathematical derivation of the general case of interfacial motion. The presented kinematic relations are important for large class of dynamic systems that comprise interfacial motion, e.g. rail-wheel contact. Reference is made to practical cases where the proposed model can be applied.

348 Click here to view scanned manuscript ICSV5 Paper Abstract Studies on the Vibrating Systems with Collision - Re- bound Characteristics of the Equivalent Stiff Surface Authors: Sadao Azuma, College of Science and Technology, Tohoku, ( Japan) Hiroyuki Ishida, College of Science and Technology, Tohoku, ( Japan) Shunichi Kono, College of Science and Technology, Tohoku, ( Japan) Volume 5, page 2889, paper no. 508 Abstract: This paper deals with an analysis concerning the chattering phenomenon of the one-degree-of -freedom systems with collision. The objective of authors is to investigate the state of rebound and contact time when the mass element of the vibratory systems run into the optional collision surface. The collision surface, on paper, is equivalently substituted by the stiffness-surface that possesses a spring and a damper. It is characterized with relative to some properties of the system model, and moreover the considerations, which is so easy in practice as for analysis of collision systems by the applications of nonlinear equivalent stiffness-surface, is indicated as a result of examine.

349 Click here to view scanned manuscript Click here for postscript-derived manuscript ICSV5 Paper Abstract Isolation of Buildings From Railway Vibration: A Case Study Authors: Dave Anderson, Arup Acoustics, ( Australia) Volume 5, page 2897, paper no. 488 Abstract: The Bridgewater Hall in Manchester, UK, forms the new home for the Halle orchestra and a major international venue for symphonic and classical music. The hall comprises a 2400 seat auditorium together with orchestral accommodation and backstage facilities. This paper presents the design of the vibration isolation system used to prevent excessive groundborne noise from the adjacent railway. Predictions and measurements are compared, showing reasonable agreement of overall results but with signiﬁcant diﬀerences in source levels, propagation losses and isolation insertion loss.

350 Click here to view scanned manuscript ICSV5 Paper Abstract On Stiffened Plate Vibration Authors: Boris M Efimtsov, TsAGI, Central Aerohydrodynamic Institute, ( Russia) Volume 5, page 2905, paper no. 481 Abstract: On the theoretical analysis basis the principal trends and regularities of the plate vibration connected with the elasto-inertial features of stif-feners are studied. The dynamic bending and torque strenth of stiffeners is taken into account in this case. The effect of these points-on frequencies and forms of the plate vibration connected with stiffeners is illustrated. The conditions are formulated at which the lowest eigen-frequency of the stiffened plate exeedes the first frequency of eigen-vibrations of its freely- supported isolated span and the distance between the knot lines of the respective vibrations form is not higher than the stiffener step. These conditions determine the relations between the elasto-inertial parameters of the plate and the stiffeners at which an essential atten-uation of the acoustic radiation of the stiffened plate at low frequencies can be realized at the expense of reducing the distance between the knot lines of its lowest forms.

351 Click here to view scanned manuscript ICSV5 Paper Abstract Experimental Determination of the Complex Moduli of Hereditary-Elastic Materials Used as Isolators Authors: Stanley G Hutton, University of British Columbia, ( Canada) Guoping Chen, Nanjing University of Aeronautics and Astronautics, ( China) Volume 5, page 2913, paper no. 456 Abstract: An investigation aimed at determining the complex moduli for a number of polymer materials is discussed. The complex moduli are determined over a limited range on the basis of transmissibilities measured on mass loaded cubic specimens subjected to controlled base harmonic excitation. Diﬀerent mathematical models of the response of the specimens are reviewed and relations between the measured transmissilbility and the moduli presented. Consideration is given to the manner in which the experimental data may be ﬁtted and to the errors that are involved.

352 Click here to view scanned manuscript ICSV5 Paper Abstract Vibration Absorbers and Metallic Damping Layers Authors: Oskar Bschorr, Aeroacoustics Munich, ( Germany) H. Albrecht, Aeroacoustics Munich, ( Germany) Volume 5, page 2921, paper no. 448 Abstract: Alternating forces on a motor vehicle induce structure vibrations, and secondary noise is emitted. The means for damping this type of noise - structure borne noise - are summarised, for instance, in VDI standard 3727: Schallschutz durch Koerperschalldaempfung The basic means comprise a damping layer, a constrained layer, and a vibration absorber. The set-up, eﬀect and dimensioning of the vibration absorber and the metallic damping layer, both of which were developed at the Aeroacoustic Laboratory in Ottobrunn, are described in the following. Vibration absorbers have been used in rail vehicles for over a decade. Wheel-vibration absorbers on the ICE train reduce noise emission at 200 km/h by 8 dB(A).

353 Click here to view scanned manuscript ICSV5 Paper Abstract A Formulation for the Forced Vibration of a Multi-Sup- ported String Authors: Benjamin A. Cray, Naval Undersea Warfare Center, ( U.S.A.) Volume 5, page 2929, paper no. 437 Abstract: This paper examines a simple model: the vibration of an infinite string resting on sets of periodic supports, which are modeled as linear spring-mass-damper systems. The q-th. set of periodic supports may be offset by a distance xq. These offsets can thus be used to create spatiallydistributed gratings along the length of the string. The objective here is to gain an understanding of the physical mechanisms that govern the vibration response of more complicated arbitrarily-stiffened elastic structures.

354 Click here to view scanned manuscript ICSV5 Paper Abstract Analysis of Coupled Vibration for the Elastically Sup- ported Beam and Spring-Mass System Authors: Yun S. Ryu, Hyundai Motor Company, ( Korea) Chong D. Choi, Hyundai Motor Company, ( Korea) Hee B. Cho, Hyundai Motor Company, ( Korea) Volume 5, page 2937, paper no. 431 Abstract: The coupled vibration of wheel-railway track system has been considered as that of a mass moving on a beam. In this paper, an analytical model is proposed to analyze the coupled vibration when the wheel travels on railway track. The railway track supported by sleepers is considered as a beam on Winklers foundations, and the wheel traveling on the railway track at constant speed is considered as a moving mass. Hertzs contact stiﬀness is assumed between the wheel and railway track. Numerical results are compared with experimental ones to verify the validity of the numerical method. The numerical method is found to be eﬃcient to analyze this system. Based on the numerical simulation, the appropriate analysis range of the beam model and the characteristics of coupled vibration are discussed.

355 Click here to view scanned manuscript ICSV5 Paper Abstract Coupled Stress Distribution in a Vibrating Rod Sub- jected to Variable Temperature and Moisture Authors: R.A. Heller, Virginia Polytechnic Institute & State University, ( U.S.A.) S. Thangjitham, Virginia Polytechnic Institute & State University, ( U.S.A.) A. Szekeres, Technical University of Budapest, ( Hungary) Volume 5, page 2945, paper no. 326 Abstract: Under dynamic load conditions thermal stresses and moisture induced stresses require the solution of coupled problems. Thermal expansion, moisture expansion (swelling) and elastic displacements may be analyzed independently for static or quasi-static loads and slowly varying temperature or moisture inputs. In that case displacements produced by Fourier heat conduction and the analogous Fick moisture transport may be dicoupled from elastic displacements. On the other hand, in hygroscopic materials, due to the Soret and Dufour eﬀects cross-coupling takes place when either of these inputs: thermal, hygroscopic and mechanical, are applied at a high rate. [equations omitted]. Using the equations, the problem of a vibrating rod immersed in an environment whose temperature and mositure content varies harmonically is solved. For comparison the stress distributions due to the individual inputs as well as due to the combined inputs will be calculated.

356 Click here to view scanned manuscript ICSV5 Paper Abstract Complete Program System for Analysis and Optimiza- tion of Rolling Rotational Connections Authors: Samo Zupan, University of Ljubljana, ( Slovenia) Ivan Prebil, University of Ljubljana, ( Slovenia) Pavle Kaiba, University of Ljubljana, ( Slovenia) Volume 5, page 2953, paper no. 325 Abstract: During the design of rotational connections used in various applications (transport machines, cranes, technological equipment, and military machines) many problems emerge already in the phase of development and analysis of substructures, i.e. various large dimension rolling bearings, screw connections between bearing rings and supporting structures, and gear pairs. Inconsistent computer support in this phase causes much diﬃculty and delay in the search for the optimal solution. Therefore we decided to design a complete program system for the analysis and optimisation of the above mentioned substructures of a rotational connection, and the adaptation of their geometric relations. All the necessary data will be stored in a common data base. For some typical rotational connections completely automated preparation of the technical documentation will be possible, using this data base. Even in the case of non typical designs we expect the automation of up to 75% of designer’s work.

357 Click here to view scanned manuscript ICSV5 Paper Abstract Parametrically Excited Vibrations of Plates Subjected to Pulsating Loads Authors: Juergen Buellesbach, Universitaet der Bundeswehr Muenchen, ( Germany) Oliver Fischer, Bilfinger + Berger Bau AG, ( Germany) Volume 5, page 2963, paper no. 313 Abstract: Starting with an introductory description of parametrically excited stability phenomena, a short outline is given of analyses found in literature.Next, a kinetic stability theory is explained which is the basis of the stability analyses performed in the following, and which can be applied to arbitrary shell constructions. In view of a numerical solution the stability equations are then transformed into a compact equation of work by applying the principle of virtual displacements. The portions obtained by this can be grouped together to form the contributions of the virtual internal deformation work and the virtual kinetic energy. Then the equations are modified with regard to buckling analyses of plates. In consideration of the time-dependent fundamental state due to the pulsating load application, a method is presented which can be used to solve the derived time differential equation system of HILLs type. This time differential equations system yields instability regions containing all unstable load-frequency combinations. Fur- thermore, it can be proved that periodically solutions, which can be represented by fourier series, exist along their boundaries.The application of the theory mentioned above and its numerical realization is explained for two plates with different boundary-conditions subjected to pulsating loads. The notewor- thy new results found out show instability regions starting at the expected resonance point at 2 ω. = · Moreover the effects of damping are illustrated and the resonance phenomena due to inertia portions of the fundamental state are discussed. Ω

358 Click here to view scanned manuscript ICSV5 Paper Abstract Smart Nonlinear Structures of Vibration Isolation Authors: V.I. Babitsky A.M. Veprik, Ricor, En Harod Ihud, ( Israel) Volume 5, page 2971, paper no. 308 Abstract: Modern condensed design often do not permit the effective use of linear flexural suspension as a universal solution for the limitation of energy transmission from machine to its foundation and vice versa. As soon as an application Involves exposure to a high level of shock, wide band random or frequency varying vibration, the internal impacts against the limiters of motion becomes the subject of serious concern. The presence of bumpers turns the vibration isolator into the strongly nonlinear (vlbro-impact) structure. The idea of this novel vlbratlon isolatlon arrangement is based on the co-operative use of lightly damped linear vibration isolation and specially tuned heavily damped bumpers. The bumpers are installed with minor oscillation space sufficient to allow impactless operation under nominal excitation and to restrict effectively excessive deflections. The main advantages of this scheme are due to the removal of motion limitation and damping duties from the flexural elements and concentrating these in the bumpers with the intelligent utilization of dynamical properties of the vibro-impact system. The study of the dynamics of a . nonlinear system of vibration isolation exposed to kinematic excitation of sine sweep, wide band random and saw-tooth shock types was conducted. Special attention was paid to the simulation of the response to suddenly applied gross intensity shock. As a result, the generalised optimal parameters of nonlinear isolation were found. The results of the simulation are compared with a series of full-scale vibration tests of a flexibly suspended linear compressor of a split Stirling cryocooler for a vibration sensitive electro-optical device.

359 Click here to view scanned manuscript ICSV5 Paper Abstract Free Vibration of A Cantilever Beam with A Partial Span of Distributed Mass Authors: Xiaoquan Wang, The Hong Kong Polytechnic University, ( Hong Kong) K.T. Chan, The Hong Kong Polytechnic University, ( Hong Kong) Volume 5, page 2981, paper no. 289 Abstract: A modified transfer matrix method is developed to obtain exact solution of natural frequencies and mode shapes of a cantilever beam loaded with distributed mass over an intermediate span. The eigenvalue problem is analytically derived, then eigenvalues and eigenfunctions are calculated numerically. As verification, free vibration of a cantilever beam with concentrated mass is studied and the computational natural frequencies agree very well to the data available in the open literature. Computational results are presented to demonstrate influence of added mass position and length on natural frequencies and mode shapes of the mass-loaded cantilever beam. It is shown that as the distributed mass shifts from the clamped end to the free one, the fundamental natural frequency decreases while the natural frequencies of higher modes vary cyclically. The nodal points of mode shapes shift with the distributed mass in a swing manner, and the amplitudes of mode shapes are suppressed at the locality of the mass. As the mass position is fixed, the effect of mass length is found to be significant for natural frequencies of higher modes, implying that in this case error will appear if a distributed mass is modeled by a concentrated one. However, when the length of the distributed mass is made rather small, say 1/1000 of the beam length, then it can be regarded as a concentrated one with great accuracy.

360 Click here to view scanned manuscript ICSV5 Paper Abstract The Case of the Vibrating Superfractionator Authors: Adolf E. Blach, Concordia University, ( Canada) Volume 5, page 2989, paper no. 271 Abstract: A tall fractionator tower, part of a super fractionation unit in an aromatics plant of a petroleum refinery was originally built by a very reputable pressure vessel fabricator with extensive experience. The fractionator used in the production of Xylene performed well for a number of years without any difficulties. Then, suddenly, when a drop in price of aromatics led to a shutdown of the unit, the empty tower started to vibrate violently at moderate wind velocities. As soon as the tower was filled with liquid, the vibrations stopped; however, over a period of 10 years with on and off vibrations, the anchor bolts were apparently stretched beyond the yield point of the material. An investigation into the strength of the foundation also showed insufficient safety against overturning. This paper describes the accumulated damage done to both, tower and foundation, also the very expensive repair work required to make the tower structurally sound. The repair took almost one year to completion, partly due to the fact that work had to be done while the refinery was on-stream. The repair, of course, did not fully eliminate the reasons for the vibrations. An automatic system had to be devised to sense vibratiom during periods of shutdown of the process unit, and automatically initiate a sequence to fill the tower with liquid whenever excessive vibrations are detected.

361 Click here to view scanned manuscript ICSV5 Paper Abstract Study on Generation Mechanism of Self-Excited Vibra- tion in Cylindrical Grinding Authors: Yoshiaki Terumichi, University of Tokyo, ( Japan) Shinichi Ohno, University of Tokyo, ( Japan) Volume 5, page 2997, paper no. 223 Abstract: Self-excited vibration in cylindrical grinding is always experienced if the work speed is high. In this paper, the eﬀect of the work speed on the occurrence of self-excited vibration is investigated analytically and numerically, and the amplitude and phase shift of the work vibration in steady state is also determined, using the averaging method with the nonlinearity of the damping force taken into consideration. The main results are as follows: First, if the work speed is low, self-excited vibration does not occur. On the other hand, if the work speed is high, self-excited vibration always occurs. The critical speed of the work revolution is given using Nyquists stability criterion. Second, if the grinding rate is large, the amplitude of the self-excited vibration increases with increase of the work speed. In the steady state, the phase of the work displacement is delayed by pi/2 to that of previous grinding for all work speed. The above theoretical result about the critical work speed is in good agreement with the experimental one.

362 Click here to view scanned manuscript ICSV5 Paper Abstract The Classification of Original Measure and Measure- ment Device Due to Their Sensitivity to Vibrations and Other Loads During Transportation Authors: Dimitrije Jankovic, University of Belgrade, ( Yugoslavia) Svetozar Jankovic, University of Belgrade, ( Yugoslavia) Volume 5, page 3005, paper no. 94 Abstract: The transportation of original measure (OM) and measurement devices (MD) is frequently performed by motor vehicles. The unusual conditions which occur due to vibrations, and temperature impact loads, as well as other disruptions during transportation have influence on the metrological characteristics of OM and MD.Due to this fact, and in the desire to choose, that is, design a motor vehicle for the transportation of OM and MD, there has been made a classification of OM and MD according to their sensitivity to vibrations and other loads, as well as to the method of packing of same and storage facilities in the vehicle, all for the purpose of securing the preservation of the metrological characteristics in transportation.

363 Click here to view scanned manuscript ICSV5 Paper Abstract Investigations of Microseismic Vibrations From Seis- mogeneous Sources as a Presage of Seismic Events Authors: T.Ho. Babayan, Institute of Geophysics & Engineering Seismology, ( Armenia) S. Karapetyan, Institute of Geophysics & Engineering Seismology, ( Armenia) H. Abrahamyan, Institute of Geophysics & Engineering Seismology, ( Armenia) Volume 5, page 3015, paper no. 440 Abstract: This work is devoted to survey the variations of amplitude-period character of microseisms in epicentral areas of expected seismic events, with the aim to solve the problem of short-term prediction of earthquakes. The investigations were carried out in the area of intersection of the south shoots of the Spitak fault and Achourian seismogeneous fault in two stages: September 1995 and June-July 1996. Earth- quakes source areas has been determined by traditional (geophysical-seimological) and non-traditional (biolocation) methods, before some months of seismic events. The graphs were made up, which show that interesting results were obtained. At the ﬁrst stage of investigations it turned out, that some houres before the seismic events anomal increasing of amplitudal level and periods of high frequency microseisms occured. After the events they are decreased to phon level. At the second stage of the works it occured again the same but only for amplitude levels, without changing of periods. As a conclusion to this studies investigations of microseisms in source areas paving seismic events make it possible to realize short term prediction of the earthquakes.

364 Author Index Ben Tahar, Mabrouk ...... II-893 V-2501 Bento Coelho, Luis ...... II-735 Besov, Alexey S...... V-2819 A Bies, David Alan ...... III-1183 Abe, Masato ...... IV-1725 Blach, Adolf E...... V-2989 Abhary, Kazem ...... V-2871 Blair, David G...... V-2765 Abrahamyan, H...... V-3015 Blazewicz, A.M...... II-531 Abramian, A.K...... IV-1797 Blotter, Jonathan D...... III-1475 V-2527 Agrawal, N J ...... III-1301 Bokor, Jozsef ...... IV-2071 Ahmed, S.R...... II-607 Boominathan, P.K...... I-485 Ahn, C.O...... II-1049 Brandt, N.B...... IV-1815 Ahuja, Krishnan K...... II-513 Brio, Moysey ...... IV-2023 Aisaka, Masaharu ...... II-1117 V-2689 Broede, Peter ...... III-1239 III-1255 Akerlof, Leif ...... II-729 Bschorr, Oskar ...... V-2921 Alarcao, D...... II-735 Buellesbach, Juergen ...... V-2963 Alauddin, M...... III-1367 Bukutu, Cecilia ...... V-2569 Albrecht, H...... V-2921 Bull, M.K...... II-531 Alekseev, V...... V-2739 Burgemeister, Kym A...... I-231 Alvarez, A...... III-1175 Burgess, Marion ...... V-2623 Anderson, Dave ...... V-2897 Busse, G...... IV-1717 IV-1741 IV-1747 . IV-1815 Andreev, Valery G...... IV-1755 Anstee, Stuart ...... V-2765 Araki, Yoshiaki ...... II-1117 V-2689 C Arenas, Jorge P ...... III-1351 Caimi, Raoul E...... II-555 II-563 Asselineau, M...... II-773 Campino, S...... V-2629 Astley, R.J...... IV-1847 Capdevila, H...... II-669 Augustynska, Danuta ...... IV-1959 Carfagni, Monica ...... IV-2247 Azad, A.K.M...... II-841 Carme, Christian ...... I-173 I-343 I-351 I-359 I-367 I-375 Azalinov, Dmitri ...... IV-1995 Carne, Thomas G...... III-1539 Azuma, Sadao ...... V-2889 Caruntu, Dumitru ...... V-2855 Azzurro, A.P...... III-1175 Carvalho, Antonio P.O...... II-757 Cato, Douglas H ...... V-2813 B Cazzolato, Ben ...... III-1659 V-2391 Babayan, T.Ho. . V-3015 ...... Challis, Louis A...... III-1127 Babitsky, V.I. . V-2971 ...... Chan, K.T...... V-2981 Bðkke, Jrgen . III-1519 ...... Chang, Yuh-Ming ...... III-1399 Bagot, Hervey . III-1593 ...... Cheewapattananuwong, Weeradej ...... Bahrami, Ahmad ...... III-1293 V-2563 Bao, Chaoying ...... I-279 Chen, Guoping ...... V-2913 Baranov, N.I ...... II-635 Chen, Rong Liang ...... III-1527 Baranov, S.N...... II-635 Cho, Dae-Hyeon ...... III-1381 Barrett, R.F...... V-2729 Cho, Hee B...... V-2937 Bartolini, Alessandro ...... II-885 Choe, Gyu-Sang ...... IV-1829 Ben-Dor, Gabi ...... IV-2031 Choi, Chong D...... V-2937

365 Chow, L.C...... II-599 Dickinson, Laurence P...... III-1207 Chwang, Allen T...... V-2805 Dobrzynski, W...... II-607 Ciccozzi, Marco ...... III-1135 Doettinger, Ch...... IV-1755 Circelli, Tony ...... III-1135 V-2569 Dohrmann, Clark R...... III-1539 Claesson, Ingvar ...... I-327 I-501 IV-2197 Don, Charles G...... III-1153 III-1415 Clark, A.J...... IV-1779 Dreiman, Nelik ...... III-1309 III-1407 Clark, Norman H...... III-1207 IV-1761 Drew, S.J...... V-2863 Coﬀen, Charles D...... IV-2295 Drozdova, Lyudmila Ph...... III-1677 V-2437 V-2443 V-2661 Couchman, Luise S...... IV-1977 Dubey, R...... III-1301 Coyette, Jean-Pierre ...... II-801 IV-1899 Duran, A...... IV-2263 Cray, Benjamin A...... V-2929 Cremers, Luc ...... II-801 Crighton, D.G...... IV-2021 E Croce, Pietro ...... III-1359 Eager, David ...... IV-1967 Crocker, Malcolm J...... I-27 Eﬁmtsov, Boris M ...... V-2905 Cummings, Alan ...... III-1431 III-1669 Eichenlaub, Christoph ...... III-1215 Cummins, R.J...... II-599 Elliott, S.J...... I-311 Cveticanin, Livija ...... IV-1931 Engel, Zbigniew ...... III-1325 Cvetkovic, Dragan S...... V-2609 Entwistle, R.D ...... III-1343 Ercoli, Liberto ...... III-1175 D Dabrowski, Zbigniew ...... III-1375 F Dai, Jue ...... V-2477 V-2493 Fedorchenko, Alexander T...... II-591 Dance, S.M...... II-765 Feng, N.S...... V-2457 Danesi, S...... IV-1741 Ferguson, Brian G...... IV-2213 Davy, John L...... II-741 Field, C.D...... III-1683 Dawe, Ross L...... III-1263 V-2797 Fischer, Oliver ...... V-2963 Day, Graham J...... V-2755 Fleming, Gary A...... III-1475 V-2527 Dean, Peter D ...... I-271 Ford, Robin ...... II-969 Deason, V.A...... III-1483 Forrest, James A...... V-2665 Debevc, Mark ...... II-781 French, Richard ...... III-1135 Deblauwe, Filip ...... V-2629 Fricke, F.R ...... III-1683 de la Croix, D. Vaucher ...... II-993 Fritz, P...... III-1459 III-1491 III-1499 III-1505 Fujisaka, Yoh-ichi ...... IV-2181 de la Iglesia, F...... II-715 Fujita, Yoshifumi ...... IV-2159 Delemotte, Virginie ...... I-367 Fuller, Chris R...... I-103 I-263 Delfosse, Michel ...... IV-1951 Fung, K.Y...... I-295 IV-1839 Deljanin, A.S...... V-2609 Furnell, Graham D ...... V-2755 De Man, Pierre ...... I-359 I-367 I-375 Derrien, David ...... I-359 I-375 Derwinski, Tricia ...... IV-2295 G Gabard, Stephane ...... III-1467 Desmet, Wim ...... IV-1879 Gade, Sven ...... III-1391 Devenport, William ...... II-547 Galbreath, Edwin R...... III-1263 V-2797 Dezelak, Ferdinand ...... IV-1941 Galiyev, Shamil U...... IV-1785

366 Gan, W S ...... IV-1771 Heiss, Alois ...... III-1511 IV-2221 Gao, Yujin ...... II-969 Heller, Hanno ...... I-59 Garcia-Fogeda, P...... II-715 Heller, R.A...... V-2945 Gardulski, Janusz ...... II-1065 Henriksen, E...... V-2519 Gargano, Enrico ...... II-885 Heron, Ken H...... IV-2287 Garnier, Bernard ...... II-993 III-1491 Hesterman, D.C...... IV-1891 III-1499 III-1505 Hijawi, M...... III-1563 Geerts, N.C.P.J...... II-857 Hiromitsu, Seijiro ...... IV-2151 Geisse, D...... IV-1747 Ho, D...... II-945 Gerges, Samir N.Y...... I-151 Hogg, Suzanne ...... III-1617 Ghasempoor, A...... II-961 Hole, Lars Robert ...... III-1167 Ghosh Roy, D.N...... IV-1977 Hossain, M.A...... I-189 I-453 I-461 Gibbs, Barry M...... V-2359 V-2449 Howard, Carl Q...... I-421 III-1149 Gil, C...... V-2593 III-1659 Ginn, Bernard ...... III-1519 Howard, Ian ...... II-869 II-1001 Girolami, G...... III-1625 Huang, Wenhu ...... II-1057 Glegg, Stewart ...... II-547 Hunt, Hugh E.M...... V-2653 Goda, Kazuya ...... V-2681 Hunter, John K...... IV-2023 Gowda, C.J. Gangadhara ...... II-643 Hutton, Stanley G ...... V-2913 Goy, Eugenie ...... II-893 Hygen, Hans Olav K...... III-1141 Griefahn, Barbara ...... III-1239 III-1255 Grosche, Fritz-Reinhard ...... II-707 I Gross, Ernestine M.A...... V-2581 Ibrahim, Raouf A ...... III-1563 Grudskii, Sergey M...... V-2781 Ih, Jeong-Guon ...... IV-2271 Grundman, J...... V-2593 Ikuta, Akira ...... IV-2055 IV-2143 Guice, Robert L...... III-1167 Indeitsev, Dmitri ...... V-2739 Guidati, G...... II-699 Inman, Daniel J...... I-115 III-1571 Guyader, Jean-Louis ...... III-1273 V-2347 Inoh, Takeshi ...... V-2689 V-2429 Ishac, Najah ...... V-2601 H Ishida, Hiroyuki ...... V-2889 Hahn, E.J...... V-2457 Ivanov, Nikolay I...... III-1651 V-2661 Hakansson, L...... I-501 Iwatsubo, Takuzo ...... I-303 Hall, Marshall V...... V-2773 V-2789 Han, Kwang Hee ...... III-1691 J Han, Yun Sik ...... II-977 Jacobsen, Finn ...... IV-2231 Hansen, Colin H...... I-205 I-213 I-421 Jankovic, Dimitrije ...... V-3005 III-1659 V-2391 Jankovic, Svetozar ...... V-3005 Hansen, Uwe J...... III-1581 III-1601 Janssens, M.H.A...... III-1547 Hanson, Donald B...... II-515 Jaschinski, Wolfgang ...... III-1239 III-1255 Hardin, Larry ...... IV-2295 Jensen, Morten Skaarup ...... II-793 Harland, N.R...... I-445 Jeon, Wan-Ho ...... III-1333 Hashmi, M.J.S...... III-1367 Jessup, B.L...... V-2789 He, Jimin ...... IV-1855 Jeswiet, J...... II-961 Heidecker, R.M...... V-2863 Jiang, Xinwei ...... II-1057

367 Jitenev, Vladimir ...... II-659 Kootsookos, Peter J...... II-1073 II-1081 Johansson, Orjan ...... IV-2255 Koss, Leonard L ...... V-2845 Johansson, Sven ...... I-327 I-477 Kosse, Vladis ...... IV-1863 Jones, Adrian D...... V-2701 Krasheninnikov, Sergey Ju...... II-659 Jones, R.W...... I-437 I-445 IV-1891 Kriegbaum, Birger ...... III-1519 Joshi, S.R...... III-1301 Krishnappa, G...... II-919 II-985 Juhl, Peter M...... II-825 Krothapalli, Anjaneyulu ...... II-625 Juniper, Ross G...... V-2383 Kryniski, Krystof ...... II-953 Juravleva, A.A...... V-2437 Kunc, Robert ...... II-849 Kuntz, M...... II-669 K Kuravsky, Lev S...... II-635 Kaczmarczyk, Stefan ...... IV-1821 Kurosawa, Kazuaki ...... IV-2305 Kaiba, Pavle ...... V-2953 Kwak, Seung Chul ...... III-1699 Kaji, Shojiro ...... II-691 Kamata, Minoru ...... IV-2305 V-2543 L Kanemitsu, Yoichi ...... I-469 Lago, Thomas ...... I-327 I-477 IV-2197 Kang, Hyun J...... IV-2329 Lai, Joseph C.S...... II-877 III-1293 Kang, Sung-Chon ...... IV-2271 Lam, K.Y...... IV-1915 Kang, Young Kyu ...... II-1109 Langeveld, C.M...... III-1547 Karantonis, Peter ...... V-2601 Larsen, Helge ...... III-1519 Karapetyan, S...... V-3015 Larsson, Ashley Ian ...... V-2747 Karra, C...... V-2501 Laugesen, S...... V-2519 Kawamura, Shozo ...... I-303 Laulagnet, B...... III-1273 Kazama, Michiko ...... IV-2079 IV-2167 Lawrence, David E. P...... III-1415 Kell, Thomas ...... III-1459 Lecomte, Christophe ...... IV-1899 Kelly, D.W...... IV-1807 Lee, Chong Won ...... II-977 Kevlahan, N...... IV-2039 Lee, Duck Joo ...... III-1333 III-1699 IV-1871 V-2635 Khirnykh, Konstantin ...... III-1431 Lee, D.W...... IV-1891 Kijimoto, Shinya ...... I-469 Lee, Seung P...... II-1049 Kikushima, Yoshihiro ...... I-413 V-2375 Lee, Young Seob ...... II-977 Kim, Hyun S...... IV-2329 Legge, Katherine A...... III-1641 Kim, Jaehwan ...... II-833 Leung, Ronnie C N ...... I-255 Kim, Jae S...... IV-2329 Lew, Henry ...... V-2729 Kim, Jae Wook ...... IV-1871 Li, Tao ...... IV-1855 Kim, Kwang-Joon ...... III-1381 IV-1829 Li, Xun ...... I-213 Kim, Sang R...... IV-2329 Li, Yuejun ...... V-2477 V-2493 Kim, Yong Seok ...... V-2635 Lighthill, Sir James ...... I-3 Kirpichnikov, V.U...... V-2437 V-2443 Lindqvist, Elizabeth A...... II-749 Kobayashi, Toshimitsu ...... III-1231 Lo, Kam W...... IV-2213 Kodani, Shoji ...... IV-2135 Lohmann, Dieter ...... II-669 Koike, T...... IV-2175 Lowet, Geert ...... V-2629 Koike, Takuji ...... III-1231 Loyau, Thierry ...... V-2429 Komatsu, H...... III-1223 Lyamshev, Leonid M...... IV-1755 Kono, Shunichi ...... V-2889

368 N M Na, H.S...... IV-2263 Mace, Brian R...... I-437 I-445 IV-2279 Nagy, Istvan ...... II-937 IV-2071 IV-2313 Nakasako, Noboru ...... IV-2103 Mano, H ...... II-1017 Nayfeh, Jamal F...... II-563 Margasahayam, Ravi N ...... II-555 II-563 Newland, David E...... IV-2043 Martin, Byron ...... III-1149 Ng, Kam W...... II-1103 Maruta, Yoshiyuki ...... II-571 Nishimura, Masafumi ...... IV-2119 Mathew, Joseph ...... II-903 IV-1863 IV-2127 Matsuda, Koichi ...... I-469 Nixdorf, K...... IV-1747 Matsuoka, Muneharu ...... II-539 Nordberg, Joergen ...... I-319 Matthews, David N...... V-2789 Nordholm, Sven ...... I-319 May, Jonathan E...... V-2653 Norton, Michael P...... II-579 Mazid, M. Abdul ...... III-1367 Norwood, Christopher J...... V-2477 McLeod, Ian Donald ...... III-1153 V-2511 Novak, R.A...... V-2419 Meerbergen, Karl ...... IV-1899 Nuutila, Olli ...... II-817 Mehta, Pramod S...... II-643 Mei, C...... I-437 Mendez, Antonio Miguel ...... III-1195 O Michel, Claude ...... IV-1951 Oddo, L...... III-1273 Mikhalkovich, S.S...... V-2781 Ogawa, Hitoshi ...... IV-2087 Millar, E...... III-1351 Oh, Jae Eung ...... III-1691 Minamihara, Hideo ...... IV-2119 IV-2127 Ohishi, Hisami ...... V-2535 Ming, Ruisen ...... IV-2321 Ohlrich, Mogens ...... V-2519 Minguez, A...... I-223 Ohnishi, Takahiro ...... IV-2079 IV-2167 Mironov, Alexei ...... II-659 Ohno, Shinichi ...... IV-2305 V-2535 V-2543 V-2997 Mirowska, Marianna ...... III-1247 Oho, Tatsuya ...... III-1555 Mitani, Yasuo ...... IV-2103 IV-2111 Ohta, Mitsuo ...... IV-2055 IV-2087 IV-2095 Mochalova, Yu ...... V-2739 IV-2103 IV-2111 IV-2119 IV-2127 IV-2135 Mohajeri, R...... IV-1807 IV-2143 IV-2151 IV-2159 Mohamed, Z...... II-841 Okuma, Masaaki ...... III-1555 Molliex, F...... III-1491 III-1499 III-1505 Omelchenko, Alexander V...... III-1651 V-2661 Mondot, J.M...... V-2449 Omerovic, Adem ...... II-1001 Montassier, Anne ...... I-173 I-351 Orozco-Santillan, Arturo ...... I-287 Moore, Thomas N...... II-961 Orsini, Pietro ...... III-1359 Moorhouse, A T ...... V-2449 O’Shea, Peter ...... IV-2189 Morgado, Antonio E.J...... II-757 Osman, Riduan ...... III-1609 Morgan, Laurie ...... II-869 II-1001 Otsuru, Toru ...... II-809 Mori, Sadao ...... II-571 Morita, Atsushi ...... I-303 Mukherjee, Binu K...... I-385 I-395 P Pan, Jie . I-279 I-429 IV-2321 V-2411 Munjal, M.L...... III-1707 ...... Pan, Xia . I-311 Musil, Milos ...... III-1571 ...... Parizet, E...... V-2347

369 Park, Hyun Chul ...... II-1109 Rennison, David C...... IV-1779 Park, S.C...... II-1049 Rew, Ho Seon ...... III-1699 Park, Y.M...... II-1049 Rew, H.S...... II-1049 Park, Youngjin ...... IV-2011 Rhee, D.I...... II-1049 Patrat, J.C...... IV-2263 Rhee, Huinam ...... IV-2011 Paurobally, R...... I-279 Rios, Rolando ...... III-1351 Pavlyukov, Eugeni V...... II-659 Ritter, S...... IV-1741 Pawelczyk, Marek ...... I-335 Rochaix, Edmundo Carlos ...... III-1195 Pedersen, Rolf C...... II-579 Rossi, Lucile ...... III-1625 Peric, Christian ...... IV-2189 Rossing, Thomas D ...... III-1601 Petrolito, J...... III-1641 Rudenko, O.V...... IV-1815 Peube, J...... III-1467 Ruyen, Ro ...... III-1399 Pfeiﬀer, F...... III-1459 Rybak, Larisa A...... V-2839 Picard, Christophe ...... III-1467 IV-2263 Ryu, Yun S...... V-2937 Pickles, J.M...... II-531 Pierini, Marco ...... IV-2247 S Pieruschka, P...... V-2553 Saeki, Masato ...... IV-1923 Pinnington, Roger J...... V-2403 Saﬁ, S.A...... IV-1807 Piovan, M.T...... III-1175 Saine, Kari ...... II-817 Pleban, Dariusz ...... III-1325 IV-1959 Salerno, A...... IV-1741 Plotnikova, L.A...... IV-1733 Salvatore, Walter ...... III-1359 Poblete, Victor ...... III-1351 Samoylov, Michael M...... III-1203 Podlesak, Michael ...... I-247 III-1651 III-1677 Ponomarenko, G.M...... III-1203 Samuels, Stephen ...... V-2563 Potekhin, Vyacheslav V...... V-2661 Sas, P...... IV-1879 Prascevic, Momir ...... V-2609 Sasaki, Kenji ...... IV-1725 Prebil, Ivan ...... II-849 V-2953 Savenko, V.V...... V-2443 Puto, Dariusz ...... IV-1959 Schmid, L.J...... IV-1779 Schnur, J...... III-1283 Schomburg, T...... III-1283 Q Schonthal, Ernst ...... III-1451 Qiu, Xiaojun ...... I-205 I-213 Schoofs, A.J.G...... III-1633 Schulten, Johan B.H.M...... II-615 R Scott, Brian L...... I-239 Radkowski, Stanislaw ...... II-1041 Sedov, Michael S...... III-1535 Ram, Yitshak M...... I-405 Seto, Kunisato ...... II-539 Ramos-Hernandez, D.N...... I-189 Shankar, Suhashini ...... III-1617 Randall, R.B...... I-133 II-945 II-969 Shenkin, Andrey V...... II-659 Rebbechi, Brian ...... II-927 Sherrit, S...... I-385 I-395 Rebillat, J.C...... IV-2263 Shi, Guangyu ...... IV-1915 Recuero, Manuel ...... I-223 V-2593 Shield, B.M...... II-765 Rehfeld, M...... I-351 Shiohata, Koki ...... I-303 Reid, Ian ...... V-2879 Shorter, P.J...... IV-2313 Reinhart, Thomas E...... V-2615 V-2643 Sim, Ah Boon ...... V-2581

370 Singaperumal, M...... I-485 Tokuhisa, Kiichi ...... II-539 Sirichai, Seney ...... II-869 Toniato, G...... V-2465 Sloss, Bruce ...... IV-2189 Tonin, Renzo ...... V-2601 Smael, J...... III-1175 Torkar, Matjaz ...... II-849 Snyder, Scott D...... I-231 Trivailo, Pavel M...... IV-1733 Sommerfeldt, Scott D...... I-239 Tso, Yan K...... V-2383 Soumelidis, Alexandros ...... IV-2071 Tsukernikov, Ilja E...... III-1317 Southgate, David ...... V-2553 Spuzic, Sead ...... V-2879 U Srinivasa, Y.G...... I-485 II-643 Uchida, Tomoyuki ...... II-809 Stanullo, J...... IV-1755 Uskov, Vladimir N...... III-1651 Starek, Ladislav ...... III-1571 Stark, U...... II-669 Stojanovic, V.O...... V-2609 V Valentin, G...... I-343 Stone, Brian J...... III-1343 V-2863 van Campen, D.H...... III-1633 Sugimura, Akira ...... IV-2181 Vandepitte, D...... IV-1879 Sukhodolsky, Anatoly T...... III-1441 Van de Ponseele, Patrick ...... V-2629 V-2829 Sun, Q...... II-985 van der Linden, P.J.G...... III-1283 Sung, C.C...... III-1399 van Eeghem, Jean S...... IV-2175 Sutton, Trevor J ...... I-311 van Houten, M.H...... III-1633 Szekeres, A...... V-2945 Venancio-Filho, F...... II-1091 Szeto, W.K...... III-1161 Veprik, A.M...... V-2971 Verbeek, G...... II-857 Verheij, Jan W...... II-857 III-1547 T Vorobjev, Pavel V...... III-1203 III-1677 Tagaeto, Tetsuo ...... III-1223 Vu, Thanh Lan ...... I-429 Takaki, Naomitsu ...... IV-2095 IV-2127 Takakuwa, Yoshiaki ...... IV-2119 Takano, E...... IV-1923 W Takemiya, Hirokazu ...... V-2681 Wada, Hiroshi ...... III-1231 Tam, Christopher K. W...... II-651 Wagner, Siegfried ...... II-699 Tanabe, Hiroo ...... II-571 Wahl, Thomas J...... V-2615 V-2643 Tanaka, Nobuo ...... I-413 V-2375 Wang, Bor Tsuen ...... III-1527 Tay, T.E...... IV-1915 Wang, Chong ...... II-877 Teh, Kian ...... II-869 Wang, Wen Yi ...... II-1033 Telschow, Ken L...... III-1483 Wang, Xiaoquan ...... V-2981 Terumichi, Yoshiaki ...... V-2997 Wang, Xuexiao ...... II-1057 Thangjitham, S...... V-2945 Wang, Yue Sheng ...... III-1423 Thompson, Jim ...... V-2765 Wang, Yu-Fang ...... II-1073 II-1081 Thwaites, Suzanne ...... IV-1761 Warner, Jeremy ...... IV-1977 Tienhaara, Hannu ...... II-817 Watanabe, Noboru ...... IV-2003 Tohyama, Mikio ...... IV-2079 IV-2167 Watkins, Simon ...... IV-2189 IV-2175 IV-2181 Weber, Reinhard ...... III-1215 Tokhi, Osman ...... I-189 I-453 I-461 I-493 Webster, D ...... II-993 III-1491 III-1499 II-841 III-1505

371 West, Robert L...... V-2527 Zlokolica, Miodrag ...... IV-1907 Wilk, Andrzej ...... II-1025 Zupan, Samo ...... V-2953 Williamson, Hugh M...... III-1293 V-2477 Zuyzlikova, Natalia V...... III-1651 V-2493 Wilson, Anders M...... IV-2337 Winberg, Mathias ...... I-327 I-477 Wismer, Niels Johan ...... III-1391 Wong, Sam W.H...... III-1161 Wong, Wai-Keung ...... III-1161 Wood, L.A...... IV-1733 Wood, R...... I-493 Wu, D...... IV-1741 Wu, Wusheng ...... V-2721 Wyckaert, Katrien ...... V-2465 X Xi, Fengfeng ...... II-985 IV-2205 Xu, K.Q...... V-2465 Y Yamagishi, Tetsu ...... II-691 Yamasaki, Yoshio ...... IV-2003 Yamazaki, Toru ...... IV-2305 V-2543 Yanagawa, H...... III-1223 Yeung, Patrick ...... V-2805 Yin, J.P...... II-607 Yokomichi, Isao ...... II-1117 V-2689 Yoshida, Keiko ...... II-627 Yoshioka, Takeo ...... II-1017 Yu, Gui Lan ...... III-1423 Yuan, Jing ...... I-295 Z Zaytseva, V.V...... III-1203 Zec, Milorad ...... V-2879 Zhang, Nong ...... III-1367 Zhang, Y ...... II-1011 Zhang, Zi Mao ...... III-1423 Zhang, Z. P...... II-1011 Zhou, Y.C...... II-1011 Zhou, Yue Qi ...... V-2673 Zhu, Xiqing ...... V-2721 Zhukov, K.P ...... II-635 Zinoviev, Alex ...... IV-1985

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