CAV Review '10-'11

Home , Reverberation

CAV Review ‘10-’11 CENTER FOR ACOUSTICS & VIBRATION CAV Update Morris Seeks to Quiet Military Jet Engines Spring workshop dates set The CAV‘s annual workshop will be held at The noise generated and radiated by modern military fighter aircraft engines represents a health haz- the Penn State Nittany Lion Inn May 9-10. On ard to carrier deck and support personnel and is annoying to communities in the vicinity of air bases. Monday, following the formal presentations, Unlike the high bypass-ratio turbofan engines used on commercial aircraft, high performance military we will offer laboratory tours to familiarize engines are very low bypass-ratio turbofans with extremely attendees with some CAV facilities. George high temperatures and exhaust velocities. Because noise is proportional to jet exhaust velocity raised and Annie Lesieutre will host a picnic for all to a high exponent, reducing it in these engines is particularly challenging. participants on Monday evening. As in the past, the program will mix presentations from There are two main sources of noise in supersonic jet engines. The dominant noise source is associated technical group leaders, international liaisons, with the turbulence generated by the mixing of the high speed exhaust with the surrounding air. The several corporate sponsors, and new govern- turbulence travels downstream at a velocity greater than the speed of sound in the surrounding air, ment liaisons. Graduate students and their giving rise to very efficient noise generation, often called Mach wave radiation. In addition, the en- advisors will be available for discussions con- gines typically operate in an off-design condition. cerning their research. While formal presenta- That is, the pressure at the jet exhaust is not equal to the external pressure. This results in a series of tions are organized to allow for the exchange expansion and compression waves in the jet exhaust. These waves are known as the jet’s shock-cell of technical information, there will be ample structure. The passage of the jet turbulence through this shock pattern results in another noise source opportunity for informal discussions. known as broadband shock-associated noise (BBSAN).

CAV lunch seminars now archived online Philip Morris, Boeing/A.D. Welliver professor of aerospace engineering, is conducting research con- CAV members may now access our previous cerned with the prediction of the noise associated with these two mechanisms. His research group is lunchtime seminar series online. Videos of the taking two different approaches. The first addresses BBSAN. It uses a steady Reynoldsaveraged Na- presentations through Fall 2009 may be vier-Stokes (RANS) solution to establish the average flow in the shock-containing jet. Then a model is viewed. This is a service to our members introduced to describe the noise sources that are scaled by outputs from the RANS solution. Predic- only, so please contact us for the site location. tions for BBSAN from single axisymmetric and rectangular jets as well as dualstream jets show good agreement with noise measurements. CAV reverberation room re-characterized Andrew Orr, a graduate student in our Acous- The second approach involves the numerical solution of the unsteady, compressible, Navier-Stokes tics Program, has re-characterized the CAV equations. The calculations include the jet nozzle, so they are able to include the effects of the nozzle reverberation room. Andrew has measured geometry and the flow upstream frequency-dependent reverberation times of the jet exit. This is especially (T60’s), the spatial variability of sound, and important for military aircraft the low-frequency modal behavior of the engine nozzles because the flow room. We will post Andrew’s thesis to our can separate or shocks can form website when it’s completed along with an inside the nozzle. The calcula- updated summary of the key room acoustic tions are computationally inten- parameters. sive and require many days (and sometimes weeks) New CAV group using 100 computer processors. We welcomed Dr. Chris Barber’s new Under- Comparisons of the predicted water Acoustics group to the CAV last year. flow and noise properties with This group conducts basic and applied re- measurements have shown search related to the propagation of sound in good results. the ocean and the systems, natural and man- made, that generate and receive sound under- In addition to predicting how water. Projects in propagation and radiated nozzle geometries affect noise, it noise often involve large scale multi-vessel is important to be able to predict ocean acoustic experiments or measurements the effect of noise reduction on instrumented acoustic ranges, while pro- devices. The use of chevrons jects in Marine Bioacoustics may involve (serrations seen on the exhausts measurements of marine mammals and fish of many new commercial aircraft habitats using a few hydrophones over peri- engines) has become popular as Contours of axial velocity at different axial distances from the jet exit showing the ods of time. Acoustical Oceanography studies a noise reduction technology. effects of chevrons on jet mixing use acoustic data to determine physical prop- These devices at the nozzle exit erties of the ocean environment. Applied re- break up the large scale, low search efforts include characterizing the per- frequency turbulent structures. They only protrude a small distance into the jet exhaust and so should formance of underwater acoustic systems, have a minimal impact on engine performance. The devices can reduce the lower frequency noise and design and development of transducers and with careful design do so without affecting the higher frequency noise that causes more human an- application of signal processing techniques. noyance.

CAV Review ‘10-’11 CAV Members Receive Honors and Awards Corporate Members and Dr. Kenji Uchino—PSEAS Premier Research ing, Distinguished Visitor Fellowship, 2011; Honor- Award, April 2011 ary Visiting Professor, College of Engineering, International Liaisons Mathematics, and Physical Sciences, University of Dr. Uchino, Dr. Seyit O. Ural, and Mr. Yuan Exeter, UK, 2011-2014 Corporate Members & Representatives Zhuang—1st place Best Poster Award for Navy Applied Physical Sciences Corp.—Marty Workshop on Acoustic Transduction Materials Whitney Coyle—ARCS Bennett-Coppersmith- Pollack and Devices, May 2010 Palmer Award ATA Engineering—Mike Yang

Dr. R. Lee Culver—Fellow, Acoustical Society of Amanda Lind—Robert Graham Endowed Gradu- Bettis Atomic Power Lab—Eric Salesky America, November 2010 ate Fellowship Dresser-Rand—Zheji Liu Electric Boat—Michael Thiel Jason Slaby and Austin Overmeyer—Vertical Kieran Poulain—PARTNER center of excellence Fisher Controls Technology International, Flight Foundation Fellowship from American 2011 Student of the Year LLC— Al Fagerlund Helicopter Society General Electric Global Research Center— Joyce Rosenbaum—Amelia Earhart Award Huangang Luo Dr. Soundar Kumara—PSEAS Outstanding Gulfstream—Kristopher Lynch Russell Powers—SMART Scholarship from the Advisor Award, April 2011; finalist in INFORMS KCF—Jacob Loverich Department of Defense and one of the top two 2010 Service Science Competition, IERC Lockheed Martin/KAPL—Steve Dunn posters at the CERS Symposium Lord Corporation—Mark Downing Dr. Jennifer Miksis-Olds—Young Investigator Martin Guitars—Albert Germick Award from ONR, April 2011 HII Newport News Shipbuilding—Kevin Samuel Denes—National Defense Industrial New Books by CAV Faculty Smith Association Award, April 2011 United Launch Alliance—Ed Heyd Advances in Aeroacoustics, in honor of Professor United Technologies Research Center—Jeff Dr. Joseph Rose—SPIE Lifetime Achievement Geoffrey M. Lilley, edited by Dr. Phil Morris, Penn Mendoza Award for NDE/SHM/Smart Structures, March State Aerospace Engineering, Multi-Science Pub- Westinghouse Electric Company—Larry Corr 2011 lishing, 2010 International Liaisons and Representatives Dr. Bernie Tittmann, Steven Lin, and Tony Engineering Mechanics: Dynamics, by Gary Gray, ISVR (UK) - Steve Elliott Huang—1st place Poster, IEEE-UFFC Sympo- DLR (Germany) - Lars Enghardt Francesco Costanzo, and Michael Plesha, McGraw- sium, October 2010 CIRA (Italy) - Antonio Concilio

Hill, 2010 INSA de Lyon—Jean-Louise Guyader Dr. Eric Paterson, Royal Academy of Engineer- KAIST—Yang-Hann Kim CAV Welcomes New Corporate Sponsors The CAV is pleased to announce four new corporate sponsors for 2010-2011.

Gulfstream—corporate liaison, Kristopher Lynch The company that evolved into Gulfstream Aerospace Corp. stared in the late 1950s when Grumman Aircraft Engineering Co., who is known for military aircraft production developed a business aircraft in Bethpage, New York. Over the years there have been mergers, however Gulfstream remains a leader in innovation and was the first to design and develop a means of reducing the sonic boom. Gulfstream puts as much effort into maintaining its aircraft as it does into manufacturing them.

Today, Gulfstream employs more that 9,700 people at seven major locations: Savannah, GA; Appleton, Wis.; Dallas; Long Beach, CA.; Brunswick, GA.; London, England and Mexicali, Mexico. Gulfstream is The World Standard in business aviation.

KCF—corporate liaison, Jacob Loverich KCF Technologies is a dynamic technology company that develops and commercializes products and solutions for industry and the military. The company was founded in November 2000 by three researchers from Penn State University and specializes in energy harvesting wireless sensors, underwater navigation and smart material devices. Their vision is to be a leader in the development of federally-funded technologies and bridge the gap to successful commercial products by establishing strategic partnerships. (more can be found at KCF’s website, http://www.kcftech.com/.

Lord Corporation—corporate liaison, Mark Downing Lord originated in Erie, Pennsylvania over 85 years ago and is now a worldwide leader in adhesives and coatings, vibration and motion control, and magnetically responsive technologies. They have provided solutions to aerospace, defense, automotive and industrial customers. Operating from the world headquarters in Gary, North Carolina, Lord has 17 facilities in nine countries with 90 strategically located sales and support centers worldwide.

Martin Guitars—corporate liaison, Albert Germick C.F. Martin & Co. is the premier builder of acoustic guitars and is the 2nd oldest family owned music instrument maker in the world. Now in its 178th year of business, Martin Guitar produces over 100,000 acoustic guitars per year and continues to be regarded as the leader in quality and tradition. In addition to guitars, Martin also manufactures and distributes guitar strings worldwide. The mission of the company is to “be the best fretted instrument and string manufacturer in the world, providing the highest quality products and service for our customers while preserving and enhancing our unique heritage”. Due to the regulation in the harvesting of several traditional wood components, Martin is active in developing acoustic guitars from alternative species and synthetic materials. Martin is committed to utilizing the most advanced technologies available in the field of vibration and acoustics to help quantify the performance of musical instruments made with traditional and alternative materials.

CAV Review ‘10-’11 Welcome New International Liaisons

The CAV is also pleased to welcome a new International Liaison – the Korea Advanced Institute of Science and Technology (KAIST) We look for- ward to interacting with Dr. Yang-Hann Kim, director of the Center for Noise and Vibration Control (NOVIC). You can learn more about the Center at: http://novic.kaist.ac.kr

Welcome New CAV Members

The CAV has experienced growth in the membership of faculty and re- utilizing advanced experimental mechanics and microstructure characteri- search staff this past year. Those who have joined us bring experience in zation techniques. The research elucidates the atomic-/micro-structure their respective fields, fresh ideas and possible avenues for research col- and physical behavior relationships in order to advance the application, as laboration. We welcome the following new members. well as improve the performance, of SMAs in smart material systems and adaptive structures. Dr. Swagata Banerjee joined the Pennsylvania State University (PSU) in August 2009 as an assistant pro- Zoubeida Ounaies joined the Pennsylvania State Uni- fessor in the department of Civil and Environmental versity in January 2011 as an associate professor of Engineering (CEE). Her ongoing research focuses on Mechanical Engineering. Previous to that, Zoubeida the identification of bridge fragility parameters from was an associate professor in Aerospace Engineering its vibration response, assessment of risk and reliabil- and Material Science and Engineering at TAMU, ity of various civil infrastructure components un- where she was the inaugural holder of the Aldridge der multihazard scenarios, time dependent reliability Career Development Professorship. She has been analysis of concrete bridges in chloride environment, awarded the NSF CAREER Award (2007), the TEES and the use of fiber reinforced polymer composites Select Young Faculty Award (2008) and the Montague for structural retrofit and rehabilitation. Her research interests also include Teaching Scholar award (2008). Her research has been the application of stochastic processes and fields in civil engineering, supported by NSF, AFOSR, NASA and DARPA. structural health monitoring and damage detection, and the analysis of different soil-structure interaction problems at bridge abutments and Dr. Sven Schmitz is an Assistant Professor of Aerospace foundations. Engineering at Penn State University focusing in the area of Wind Energy. Following his Ph.D. in 2006 he was Brian R. Elbing has been a research faculty member awarded several research grants from the U.S. Army at the Applied Research Laboratory at Pennsylvania Aeroflight Dynamics Directorate (AFDD) and worked as State University since November of 2010. His re- a CFD consultant for the General Electric (GE) Wind search focus is in the area of multiphase, high Rey- company. In 2010, Dr. Schmitz joined the faculty in nolds number experimental fluid mechanics and Aerospace Engineering at Penn State University. Dr. flow-induced noise. He has spent the past six years Schmitz’s expertise is in vortical wake flows around at the University of Michigan as a graduate student wind turbines and helicopters. His background in Hy- and postdoctoral research fellow studying drag brid CFD/Vortex methods make him an expert of the complex nature of reduction technologies for surface ship applications. vortex sheets emanating from rotating blades and their roll-up and con- While at the University of Michigan, Brian received vection process downstream of the rotor. His past work on ‘Vorticity Em- his PhD and MSE degrees in mechanical engineer- bedding’ concerned the physically correct representation of vortex sheets ing. He also has his BS in mechanical engineering from Western Michigan within a CFD flow solver domain that intrinsically satisfies the conserva- University. tion of sheet circulation and vorticity.

COL (ret.) Samuel S. Evans joined the Vertical Lift Jonathan Pitt joined the Computational Mechanics Research Center of Excellence (VLRCOE), in the division of the Applied Research Laboratory in June Aerospace Engineering Department 3 years ago after 2010, after spending a year at the US Army Corps of a 27 year career in the U.S. Army, where he served Engineers Cold Regions Research and Engineering as an aviation logistician, and helicopter pilot, spe- Laboratory. He received his BS in Physics and cializing in aviation maintenance. He flew both UH- Mathematics from Lebanon Valley College, and 1 and UH-60 aircraft and culminated his career as earned both his MS and PhD in Engineering Science the Chief of Aviation Logistics at the Pentagon. He and Mechanics at PSU. His research expertise is in brings decades of hands-on rotary wing experience computational solid and fluid mechanics. Past and to the faculty and students at PSU. COL Evans re- current projects have focused on nuclear reactor ceived his B.S. from the USMA in1985, his M.S. from the Army command coolant modeling, damage mechanics in thermoelas- and Staff College in 1996, and his M.A. Army War College in 2006. tic materials, outdoor acoustic propagation, and flow evolution in open seas. In his spare time, he volunteers with the Boy Scouts and enjoys trav- Dr. Reginald F. Hamilton is an Assistant Professor of eling. Engineering Science and Mechanics at Penn State and a member of the Active Structures interest group of CAV. Dr. Hamilton earned his B.S. in mechanical engineering from Southern University and M.S. and Ph.D. in mechanical engineering from University of Illinois, Urbana-Champaign. Dr. Hamilton’s research group characterizes different classes of Shape Memory Alloys

CAV Review ‘10-’11 Featured Research

Rather than generating a grid that follows the details of the surfaces of the chevrons, an immersed boundary method is being used to simulate them. In this approach, the effect of the chevrons is simulated with a distribution of forces that brings the flow to rest inside the chevrons. This approach saves significant computer time, and initial results from it are very promising.

Morris’ research in jet engine noise is being supported by the Naval Air Systems Command (NAVAIR), Pratt & Whitney, the Boeing Company and NASA.

Instantaneous density gradi- ent contours in an underex- pended superconic jet.

Students do research for ESPN the Magazine

A recent ESPN magazine article ("These go to 11," ESPN the Magazine 15 Nov 2010) ranked the top collegiate basketball arenas according to “noise potential.” The top five arenas were listed as Kansas University, Duke University, New Mexico University, Kentucky University and Florida Univer- sity. The rankings were established by a team of Penn State Acoustics students using the theory for sound build up in large rooms, since actual measurements were infeasible. Both diffuse field and direct field contributions of the sound pressure were estimated at center court for octave band frequencies from 125 Hz to 4 kHz. Seating geometries, materials and other relevant information were collected for each arena and used with estimated absorption coefficients to determine the room constant and critical distance. The diffuse field contributions were then combined with approximate sources terms based on the seating capacity of the arena, the proximity of the fans to the court and whether they were students. The sound pressures were then combined into a total A-weighted sound pressure level and used to determine the ranking. The direct and reverberant contributions of each arena were then compared to establish the positive and negative aspects of each arena in terms of noise potential. This comparison reveals how Kan- sas and Duke reached the top of the ranking, despite having drastically different arena geometry and capacity.

Researcher (from left) Andrew Bernard, and students participating on the project are Andrew Christian, Brian Cranage, Micah Shepherd, Kieran Poulain, Neal Evans, Andrew Orr, and Dan Domme. Dr. Steve Hambric (at far right) is the advisor.

CAV Review ‘10-’11 Technical Research Group Highlights

Acoustics Characterization of Materials Control Technical Group is to pursue strategies Title: Actuation of Miniature Trailing Edge Ef- Bernhard R. Tittmann, Group Leader for reducing vibration and noise in engineering fectors (MiTEs) for Rotorcraft Applications [email protected] systems. This involves the development of active Sponsor: NASA / Army Vertical Lift Research materials and devices, accurate modeling ap- Center of Excellence (VLRCOE) The mission of the Acoustics Characterization of proaches, passive control methods, discrete and Summary: This research deals with the develop- Materials group is to develop a new under- distributed sensors and actuators as well as ment and testing of an actuator for a Miniature standing of how various types of waves, i.e., placement strategies, structural integration Trailing- Edge Effector (MiTE). MiTEs can be ultrasonic x-ray, thermal, optical, electromag- methods, fast and stable adaptive control algo- used to address stall alleviation, flight control, netic, acoustic, etc., interact with advanced mate- rithms, and experiments to evaluate real-world and vibration reduction. The optimal deploy- rials; to translate this understanding into tech- performance. In complex mechanical/acoustical ment schedule for MiTEs is an on/off type de- niques for monitoring and controlling industrial systems with multiple sensing and source/ ployment as opposed to a single-frequency har- processes; and to apply these techniques to the actuator locations, significant challenges remain. monic deployment. In this work, the desired on/ development of materials processes. off square-wave deployment is approximated by a five-term Fourier series. A piezoelectric bi- Brian Reinhardt, earned his Masters Degree in Professor George Lesieutre and his students are morph was designed to minimize the required Engineering Science and Mechanics in May 2010 pursuing a number of projects in vibration con- drive voltage and integrated into an airfoil sec- and he is now pursuing a trol and active structures. Working with Prof. tion for verification of the design under aerody- Ph.D. in Engineering Science. Frecker's group, and with the support of the namic loading. The MiTE had a height of 1% of Brian completed an internship National Science Foundation, they are pursuing the chord and was located approximately 10% of with Hitachi in Japan furing the development of high-strain-capable ceramic the chord upstream of the trailing edge. A bench Fall 2011. He continues his materials. The National Rotorcraft Technology test was conducted to verify the actuator dynam- study of nonlinear ultrasonics Center (NRTC) supports a project that involves ics and the required deflections were obtained on tensile specimens. Brain can the active deployment of small trailing-edge without exceeding the limits of the piezoelectric be reached at devices to improve rotor performance. The Lord material. Results showed that the flap deflection [email protected]) . Corporation sponsors a program to improve the approximated a square-wave for angles of attack dynamic behavior of helicopter lag dampers. of 0.84° and 12° and wind speeds up to 40 m/s. Xiaoning Xi earned her Masters Degree in Engi- Finally, NASA supports a research effort that Student: Michael Thiel, Ph.D. expected Decem- neering Science and Mechanics in May 2010 and aims to damp vibrations of integrally-bladed ber 2011 she is now pursuing a PhD in turbomachinery rotors using piezoelectric mate- Engineering Science. She is rials. Title: Reduction of High-Cycle Fatigue in Inte- studying biological cells via grally Bladed Rotors through Piezoelectric Vi- atomic force microscopy as a Title: High-Strength High-Strain Structures Us- bration Damping and Control part of the group’s Department ing Ceramic Cellular Contact-Aided Compliant Sponsor: NASA Glenn Research Center of Engineering-funded cellulose Mechanisms (C3M) Summary: A robust vibration damping system research project. Xiaoning can Sponsor: NSF for integrally bladed rotors can dramatically be reached at [email protected]. Summary: Cellular Contact-Aided Compliant reduce high-cycle fatigue in turbomachinery. Mechanisms (C3M) are cellular structures with Such a system can be implemented using piezo- Christian Gross, a graduate student at the Swiss integrated contact mechanisms that provide electric materials in both passive and active Federal Institute of Technology Zurich, did re- stress relief. C3M are capable of large strains roles. Current research focuses on semi-active search in acoustics, ultrasound and non- compared to their bulk material constituents resonance de-tuning, and modeling using an destructive evaluation of materials with the and, due to the stress relief, are capable of even assumed-modes method. The approach involves group for two months during 2010. greater strains than their non-contact cellular detuning the structural resonance frequency counterparts. Originally developed by Drs. from a (changing) excitation frequency by alter- Yihan Tian, a graduate student at the University Frecker and Lesieutre for the skin of morphing ing the structural stiffness (by switching the of Windsor (Canada), did research in acoustic aircraft vehicles, C3M have the potential to be electrical boundary conditions of a piezoelectric microscopy on biological samples with the used in many applications requiring large strain. element), thus limiting the structural dynamic group for two months during 2010. In this project we are developing integrated response. Including a switch back to the original design and fabrication methods for high- stiffness state, detuning requires two switches Mohan Basnet, an undergraduate student at strength high-strain ceramic C3M. Ceramic ma- per resonance / excitation frequency crossing, Southeastern Louisiana University, did research terials are of interest because of their high orders of magnitude fewer than other state in optical nondestructive evaluation on thin strength particularly at the mesoscale, with over switching approaches that require four switches films with the group for three months during 2 GPa bend strength, and potential high tem- per cycle of vibration. The detuning method 2010. perature capability. Bulk ceramic materials also provides the greatest normalized vibration re- have high strength, but low strain at failure, duction for slow sweeps, low damping, and high Post doc Matthew Kropf ([email protected]) perhaps 0.2 – 1.0 percent, depending on the size. coupling coefficient. received a $100,000 Ben Franklin Technology In contrast, ceramic C3M are capable of ultimate Student: Jeff Kauffman, Ph.D. expected Decem- Partners award to fund biodiesel research. strains of 11 to 13 percent, an order of magnitude ber, 2011 higher than the ultimate strain of the bulk mate- Adaptive Structures and Noise Control rial. This project brings together expertise in Title: Multi-State Lag Dampers George Lesieutre, group leader materials, fabrication, modeling, and design. Sponsor: Lord Corporation [email protected] Collaborators: Dr. Mary Frecker (ME), Dr. Jim Summary: A multi-state lead-lag damper is de- Adair (MatSci) signed to reduce damper forces when damping The mission of the Active Structures and Noise Student: Samantha Cirone, M.S. expected 2011 is not required. This is achieved via a set of bypass channels than can be opened or closed in

CAV Review ‘10-’11 Technical Group Research Highlights

order to vary the damper forces. A first genera- tery systems engineering, and advanced actua- NSF is currently supporting an EFRI project in tion prototype was built and bench tested to tors. smart structures with Prof. Kon-Well Wang and validate the multi-state behavior. Additionally, two other PIs from Michigan and Prof. Chuck to predict the damper behavior, an analytical Smart Structures. Our focus has been on the Bakis here at Penn State. The overall goal of this model and a computational fluid dynamics model-based control of distributed parameter research is to create a transformative multifunc- (CFD) model using the commercial program systems. Distributed parameter models accu- tional adaptive structure concept through investi- FLUENT were developed. The prototype rately represent the physics of many electrome- gating the unique and desirable characteristics of damper was bench tested over a range of fre- chanical systems. These models typically con- plants; in- quencies and dynamic displacements in both the sist of partial differential equations (PDEs) for cluding nastic open and closed configurations. Comparison the distributed mechanical subsystem, bound- (rapid plant Fluid- between the open and closed configurations ary conditions, electromechanical coupling motions) demonstrated the ability of the bypass channels equations, and ordinary differential equations actuation to reduce damper force by more than 70%, with (ODEs) for the electrical subsystem. Applica- with large the capability to tune this value by varying the tions include flexible cable cranes, high-speed force and bypass channel diameter. The CFD model allows machining spindles, active noise control sys- stroke and detailed investigation into the internal flow dy- tems, flexible robot arms, marine cable systems, self-sensing/ namics of the damper device and is able to cap- and high-speed web and fiber handling sys- reconfigura- ture the general shape of the experimental force tems. Traditionally, the distributed equations tion/healing. More specifically, we propose to vs. displacement hysteresis loops. The initial are discretized to a finite number (N) of low develop and investigate new bio-actuation/bio- bench testing and CFD study verify the validity order modes, resulting in a set of ODEs that can sensing ideas building upon innovations inspired of the bypass damper concept, and prove the be used for control design using standard tools. by the mechanical, chemical, and electrical prop- device ready for the next stage of development For systems with low damping, however, erties of plant cells. We have already demon- and testing. choosing N too small can cause spillover insta- strated the vibration isolation characteristics of a Collaborator: Dr. Edward Smith (Aerospace) bilities in the high order modes. Alternatively, fluidlastic cell coupled to a mass. The figure Student: Conor Marr, Ph.D. expected December choice of a large N may result in a high order shows the theoretically predicted and experimen- 2011 compensator that is difficult to implement. tally demonstrated transmission isolation zero at around 28 Hz. One of our challenges in this pro- Title: Radial Bearing Isolator for Helicopter Using Lyapunov-based approaches that do not ject is to extend the initial success in a discretized Noise Reduction require discretization, we design controllers structure to a distributed, hypercellular structure. Sponsor: Fellowship that asymptotically stabilize the distributed Summary: Main transmission bearings are of model. This mathematically elegant method Advanced Actuators. Working with colleagues in critical importance to flight safety, noise, and eliminates the spillover instabilities associated the Electrical Engineering department, we are maintainability/reliability. Reduced cabin noise with traditional control approaches, produces helping to develop small and lightweight actua- is becoming more critical as hearing loss issues simple, low order, physically intuitive control- tors for vehicles and medical applications. develop for DoD passengers. A major source of lers, and is applicable to nonlinear systems. AFOSR is currently supporting a project to de- noise is gear-meshing vibration that is transmit- The ap- velop piezoelectric (PZT) actuators and wings for ted to the cabin via hard mounts, bearings, and proach Nano Air Vehicles (NAVs). Prof. Srinivas Tadi- the housing. Considerable research has ad- applies gadapa and MRL team members invented the T- dressed interior noise reduction strategies. In mathemati- beam actuators that general, these involve modification of the vibra- cal tools provide two-axis tion and acoustic transmission paths from the based on displacement from gearbox to the cabin. Examples include the use functional bulk PZT structure. of mounts to isolate the gearbox from the fuse- analysis, These actuators have lage, and tailored fuselage panels. Passive ap- semigroup been integrated with proaches are preferred, but are not always capa- theory, and Lyapunov’s Direct Method to a polymer flexures to ble of meeting demanding requirements. This specific mechatronic system. In addition, produce the clap- research is pursuing a multilayered metal- Lyapunov-based techniques such as adaptive ping wing NAV shown at right. elastimer bearing isolator that will reduce the and backstepping control can be used to ac- vibration transmitted from the gearbox to the count for parametric uncertainty and electrical EAP Actuators for Braille displays are being de- transmission housing and noise to the cabin. dynamics, respectively. Unlike most research- veloped under funding from NIH. Prof. Qiming Collaborator: Dr. Edward Smith (Aerospace) ers in this area who focus exclusively on mathe- Zhang provides the materials that are then cast Student: Pauline Autran, M.S. expected 2012 matics, we experimentally implement the pro- into films, stretched to the desired thickness using posed controllers and demonstrate the im- a zone heating machine, placed on frames, MECHATRONICS RESEARCH LAB proved performance provided by the control. sprayed with conductive polymer electrodes, This often requires the development of novel laminated to form a bi-layer, cut and wound into C. Rahn - Director mechatronic sensing and actuation schemes to tubes, thermally bonded in a vacuum oven, and measure the required feedback variables and metallically electroded on the top and bottom to The Mechatronics Research Lab specializes in a apply the required system inputs. The figure form a longi- multi-physics model-based approach to control shows, for example, a distributed parameter tudinal and design of mechatronic systems. The re- model-based control experiment for repetitive straining search has been supported by funding from NSF, learning force tracking in a whisker sensor for actuator. NIH, AFOSR, ONR, Army, DOE, DOC, and the Navy. Many of the industry. Research in the MRL is currently con- steps in this centrated in three areas: Smart structures, bat-

CAV Review ‘10-’11 Technical Group Research Highlights

process have been automated using mecha- contact cellular counterparts. Originally devel- Flow-Induced Noise tronic systems designed and fabricated in the oped by Drs. Frecker and Lesieutre for the skin of Dean Capone—Group Leader MRL. morphing aircraft vehicles, C3M have the poten- [email protected] tial to be used in many applications requiring Battery Systems Engineering. Prof. Chao- large strain. In this project we are developing The mission of the Flow-Induced Noise Group of Yang Wang and MRL team members are the integrated design and fabrication methods for the Center for Acoustics and Vibration is the originators of the new field of battery systems high-strength high-strain C3M made of both me- understanding and control of acoustic noise and engineering. We have funding from DOE and tallic and ceramic materials. Recent efforts have structural vibration induced by fluid flow. A industry to develop model-based estimators focused on design, fabrication, and testing of summary of the accomplishments of the mem- and battery management systems for hybrid meso-scale C3M with curved walls. The curved bers of the Flow-Induced Noise Technical Group vehicles. Norfolk Southern and DOE are sup- walled structures are capable of higher global is presented below. porting the development of hybrid locomotives strains and are better suited for meso-scale fabri- like the NS-999 that was unveiled last year. cation than C3M with straight walls. Dr. Stephen Hambric continues to consult for the This work involves the development of first Collaborators: George Lesieutre (Aerospace Engi- NRC on flow-induced vibration and fatigue principles models of the diffusion and electro- neering) and Jim Adair (Materials Science & Engi- failure problems in U.S. commercial nuclear chemistry that govern battery dynamics. The neering) power plants. figure at right compares the results for a re- Students: Vipul Mehta (PhD August 2010, pres- Dr. Dean Capone and Dr. Bill Bonness are con- duced order Li-Ion battery model (solid lines) ently at Intel Corp.), Greg Hayes (PhD May 2011), tinuing to work with two graduate students in with an experimentally validated CFD model and Samantha Cirone (MS expected August 2011) flow-induced noise. Ms. Alexandria Salton is (circles), showing excellent agreement for cur- investigating the use of rings of accelerometers rent density (a) and Lithium ion concentration Title: Nanoparticulate Enabled Surgical Instru- for non-intrusively determining the acoustic on the active particle ments pressure inside a water filled piping system. Mr. surfaces (b) and in the Sponsor: NIH Neal Evans, following on the work of Dr. Bill electrolyte (c). These Summary: The project is focused on developing Bonness, is examining the effect of roughness on reduced order models design and fabrication methods for meso-scale the low wavenumber portion of a turbulent can then be used as the surgical instruments. The target application is boundary layer. The work will use the facilities basis for Kalman filters natural orifice transluminal endoscopic surgery, developed by Dr. Bonness during his Ph.D work. and parameter estima- where small flexible surgical instruments are re- Both students are expected to graduate in Sum- tors that predict real- quired to advance this incision-less technique. mer 2011. time state of charge, Recent efforts have focused on developing design Dr. Timothy A. Brungart, Mr. Steven D. Young internal battery condi- methods for instruments with improved perform- and Dr. Dean E. Capone recently completed an tions, and state of health. Dynamic current ance by implementing multiple materials and effort to identify means of reducing the cooling limits, based on minimizing the predominant multiple contact surfaces. Recent work has also fan noise from a chassis housing electronic com- damage mechanism, enable long lived energy been directed at testing prototype instruments in ponents for a major electronics manufacturer. storage systems. surgical simulation to quantify and compare their Replacement fans and mounting modifications performance to commercially available instru- were identified that provided equivalent cooling Students and Graduation Dates ments. airflow rates and predicted sound power reduc- Bin Zhu (PhD), Spring 2014 Collaborators: Jim Adair (Materials Science & tions of up to 20 dB in level. The electronics Chris Ferone (MS), Spring 2013 Engineering), Abraham Mathew manufacturer intends to implement the alterna- Githin Prasad (PhD), Spring 2013 (Gastroenterology), Randy Haluck (Surgery), tive fans and mounting arrangement into their Kiron Mateti (PhD), Summer 2011 Chris Muhlstein (Materials Science & Engineer- next generation chassis. Lloyd Scarborough (PhD), Winter 2012 ing) Drs. Dennis McLaughlin his work in supersonic MICHAEL ROBINSON (MS), Spring 2012 Students: Milton Aguirre (PhD May 2011), Greg jet noise. During the past year he work has Nicolas Kurczewski (PhD), Spring 2015 Hayes (PhD May 2011), Jiening Liu found that beveled exits for subsonic nozzles Rory Byrne-Dugan (MS), Spring 2012 rotate the jet plume and primarily reduce noise Varma Gottimukkala (MS), Spring 2011 Title: Passively Morphing Ornithopter Wings through the subsequent rotation of the acoustic Ying Shi (PhD), Spring 2013 Sponsor: AFOSR field. Until recently, this was believed to be the Zheng Shen (PhD), Winter 2014 Summary: The goal of this project is to provide case for beveled exits on supersonic converging-

increased lift and agility in ornithopters through diverging nozzles. The jet plume from such noz- Professor Mary Frecker and her students are passive wing morphing. A compliant spine has zles was examined and shown to deflect less pursuing a number of projects related to active been developed that is flexible during the up- than 6 degrees for both over-expanded and un- structures. stroke and stiff during the downstroke to provide der-expanded flows. Therefore any measured wing morphing inspired by the continuous vortex Title: High-Strength High-Strain Structures noise reduction is due to the alteration of the gait in bird flight. Recent efforts have been aimed Using Ceramic Cellular Contact-Aided Compli- noise generation mechanisms and not the deflec- at developing optimization methods for the com- ant Mechanisms (C3M) tion of the jet plume. pliant spine including dynamic effects, and at Sponsor: NSF testing the compliant spine in bench top experi- Summary: Cellular Contact-Aided Compliant ments to quantify the lift and thrust achieved. Machinery Prognostics and Condition Mechanisms (C3M) are cellular structures with Ongoing work includes expanding the design novel integrated contact mechanisms that pro- Monitoring method to provide morphing in bending, sweep, Karl Reichard, group leader vide stress relief. C3M are capable of very large and twist simultaneously. [email protected] strains compared to their bulk material con- Collaborators: James Hubbard (University of stituents, and, due to the stress relief, are capa- Maryland) The Machinery Prognostics and Condition Moni- ble of even greater strains than their non- Students: Yashwanth Tummala

CAV Review ‘10-’11 Technical ResearchGroup Research Group Highlights toring Technical Group is focused on methodologies and technologies for accurate and reli- Tactical Wheeled Vehicle Health Monitoring Current able assessment of equipment condition and ARL Penn State conducted testing for the US Sensor predicting remaining useful life in machinery. Army Material Systems Analysis Activity Below are descriptions of one current and one (AMSAA) to develop a health monitoring for recently completed project. alternators on Army heavy trucks. The primary objective of this work was to leverage laboratory Temperature Wind Turbine Health Monitoring based power generation device health manage- Sensor Researchers from the Applied Research Labora- ment research and technology development re- tory and the Aerospace Engineering Depart- sults and apply them to a field system as an em- ment are working with the Penn State Center bedded solution. This technology development for Sustainability (CfS) to demonstrate health effort, though focused on ground platform alter- Accelerometer monitoring concepts on a CfS wind turbine at nators, was intended to provide solutions that can Figure 3: Alternator instrumented for health monitoring Penn State. The CfS wind turbine is a South- be applied to various types of power generation testing. west Windpower Whisper 500 with two blades devices. It project investigated methods to relia- and a peak capacity of three kilowatts of power. bly detect various alternator faults with a mini- The project was led by Jeff Banks, Jason Estep mum number of sensors and which required and Mark Brought from ARL. minimal additional processing of the sensor signals. Helicopter Electrical System Health Monitoring The OH-58D Kiowa Warrior helicopter has been Housing Stator Regulator a workhorse for the U.S. Army for decades and is projected to continue to accrue flight hours for years to come as a highly capable platform applied against various mission profiles. The U.S. Army is interested in the implementation of condition based maintenance (CBM) for this platform to increase operational availability of the aircraft, reduce the required number of maintenance activities and increase the inspection Fan Blades Rotor Assembly Rectifier Diodes in Housing Figure 1: Whisper 500 wind turbine at the Penn State interval period. The CBM methodology and Center for Sustainability. Figure 2: Main alternator components. these objectives are directly dependent upon the Brenton Forshey, a graduate student in Aero- The ARL project used a combination of laboratory capability of the health and usage monitoring space Engineering, is working to implement and field testing of alternators with seeded faults. system and its ability to detect diagnose and health monitor on the turbine blades and the The faults include bearing (mechanical) faults and provide an estimate of remaining useful life electrical generator. The wind turbine is cur- winding (electrical) faults. The vehicle was used (RUL). rently instrumented with voltage and current as the test bed for this program was a Freightliner sensors to each of the generator’s three output 915 truck heavy truck, similar to heavy commer- The Applied Research Laboratory at The Penn- phases and a 3-axis accelerometer on the mast cial trucks. The alternator was instrumented with sylvania State University (ARL Penn State) has supporting the turbine nacelle. Additional voltage, current, temperature and vibration sen- developed prognostic technologies for helicopter sensors monitor the meteorological conditions sors, as shown in Figure 3. We were able to suc- electrical power systems that can be integrated at the site and the energy storage system. cessfully detect both the mechanical and electrical into an existing on-board Health and Usage faults in the alternator. Monitoring System (HUMS). The goal of the Blade and gearbox failures are two of the most program was to develop a capability to monitor, critical failures in full-scale commercial wind A key finding from the study was the require- detect and provide an estimated remaining use- turbines. Previous studies have shown that ments for doing prognostic health assessment of ful life RUL for the starter/generator, battery gearbox faults are initiated by unsteady loads the alternator electrical faults. Simple fault detec- and power inverter. The focus of this effort was on the generator shaft bearings. One goal of tion and diagnosis (alternator has a fault and is no to develop technologies that provide actionable the present measurements is to characterize longer providing current) is possible using typical prognostic information for forecasting part re- unsteady wind loads on the turbine. Failure low sample rate sensing and minimal embedded placement and to extend existing time and usage modes being studied include mass and aerody- signal processing. Detection of early indicators of -based maintenance intervals. namic blade imbalance, power electronic fail- the electrical (and mechanical) faults requires ures and battery energy storage system failures. higher sample rates and the ability to perform In order to provide a focus for the technology Recent measurements also included the use of a frequency analysis and signal demodulation. development effort, a FMEA was conducted for wireless accelerometer mounted on the turbine These results are being used to develop perform- each power system component. The activities nacelle. Additional drive train testing will be ance specifications for next generation vehicle performed for this analysis included: conducted on the ARL mechanical diagnostic health management systems. test bed using load conditions measured on the • Acquired maintenance data and conducted wind turbine. interviews with the OH-58D contract maintenance personnel at the Aviation Center Logistics Participants in the project include Dr. Karl Command at Fort Rucker. Reichard, Mr. Mark Turner, and Mr. Nate Lasut • Conducted interviews with Kiowa Warrior from ARL, and Dr. Dennis McLaughlin Brenton Maintenance Test Flight Examiner (United Forshey (student) and Dr. Susan Stewart, from Stated Army Safety and Standardization Direc- the Department of Aerospace Engineering. torate (USASSD)) tasked to inspect maintenance

CAV Review ‘10-’11 Technical Group Research Highlights

are mounted around the shaft on specially de- operations in all U.S. Army OH-58D units. NER research projects is to better synthesize signed brackets at increments of 120°. A sample • Conducted interviews with Army employee sonic boom signatures that might be heard on torsional vibration frequency spectrum for a who repairs Kiowa Warrior inverters at Toby- the ground in the vicinity of buildings, incorpo- reactor coolant pump is shown in Figure 5. hanna Army Depot. rating the sound reflecting from the buildings.

Another project is related to the en-route noise of The system was tested in the laboratory using Based on the FMEA results for each power sys- jet aircraft while at cruise conditions at altitude. scaled shafts with seeded faults and in a seeded tem component, each health management tech- En-route noise is a particularly important topic fault test conducted at the Jeumont Industrie nology development team focused their develop- for assessing the noise impact of aviation on U.S. IRIS 41% RCP impeller test loop in France. The ment on the most critical failure modes. The National Parks and other wilderness areas. worked conducted on the Jeumont IRIS pump primary failure mode for the starter-generator is Studies at Penn State in 2010 have shown that test loop showed that ARL's torsional processing brush wear. For the battery, there is no single having knowledge of the humidity as a function approach proved viable in detecting and track- dominant failure mode, but instead the process of height for atmospheric attenuation coefficients ing changes in natural frequency due to cut indicated that general monitoring of the battery leads to more accurate predictions of en-route depth. A medium scale torsional test rig was state of charge and state of health could reduce noise heard on the ground. designed and developed using an existing plat- overall maintenance costs. The primary failure form at ARL. The enhancements made to the mode for the power inverter is failure of the Penn State’s research on predicting the loading existing platform allowed the additional capa- current source indicator and transistors. Diag- forces on buildings due to sonic booms for bilities of providing torsional and lateral load to nostic and prognostic systems were developed NASA also continued in 2010. Two complemen- a rotating shaft. The test bed used for experi- for each of these three electrical subsystems. tary models for low frequency and high fre- mentation consists of a 30 horsepower DC elec- quency content have been developed and re- tric drive motor, a 75 horsepower DC electric fined. The finite difference time domain ap- load motor, and a 12 ton capacity hydraulic ram. proach works well for low frequencies, and the Torsional load can be applied using the 75HP combined ray-trace/radiosity method works load motor, and a lateral load can be applied at well for high frequencies. Our work in the next the shaft’s midpoint using the hydraulic ram. few months is to seamlessly combine these ap- The results of torsional vibration measurements proaches to provide NASA a full-frequency pre- made over several incremental crack depths are diction method for building loading due to arbi- shown in Figure 6. Figure 4: Starter-generator brush wear prognostic algorithm. trary sonic boom signatures.

The project was led by Jeff Banks, Todd Batzel, Graduate Students: Robert Keolian, Matt Poese, Terrance Lovell (student), Mitch Lebold, and Karl Reichard of Propagation and Radiation Amanda Lind, M.S. spring 2011, Ph.D. expected the Applied Research Laboratory. Victor Sparrow—Group Leader spring 2013 [email protected] Thesis topic: Terrain reflection and post-boom Structural Health Monitoring noise for low-boom sonic booms Mitch Lebold and Martin Trethewey recently There were many highlights in 2010 for the Sponsor: FAA completed a multi-year project for the Electric Propagation and Radiation Group. There have Advisor: V. Sparrow Power Research Institute (EPRI) which investi- been a number of new research projects begun, gated the development of a torsional line shaft and several other projects have successfully Kieran Poulain, M.S. expected fall 2011 health monitoring system that can be applied to wrapped up. Thesis topic: Atmospheric profile effects on the any system containing a rotating shaft, such as: propagation of aircraft en-route noise reactor coolant pumps, centrifugal charging Our work with Wyle, Arlington, VA continues. Sponsors: FAA and Volpe National Transporta- pumps, condensate and feed water pumps. One project on sonic boom transmission into tion Systems Center Laboratory and field tests have demonstrated buildings using finite elements completed, and Advisor: V. Sparrow that torsional vibration features are particularly another began on sonic boom focusing. Both sensitive to shaft cracking detection and growth projects originate at NASA Langley Research Alexandre Jolibois, Ph.D. expected summer 2013 trending. Although the failure of some of these Center, and we are very grateful to collaborate Thesis topic: Optimization of high-speed rail pumps in power plant applications due to shaft with Wyle as subcontractors. In the new sonic noise barriers using a boundary element ap- cracking does not generally result in unit trips or boom focusing work Penn State will also be proach reduced power operation, the unexpected failure working closely with Gulfstream Aerospace Sponsor: Graduate Program in Acoustics and can create maintenance scheduling problems and Corp. of Savannah, GA. French building research center (CSTB) increased safety risk. Advisors: V. Sparrow, D. Duhamel, J. Defrance New projects began in 2010 on outdoor propaga- The prototype torsional vibration measurement tion and the optimization of aircraft flight paths Joyce Rosenbaum, Ph.D. spring 2011 system consists of a combination of off-the-shelf near military bases. Both of these new projects Thesis topic: Advanced acoustic propagation and specially designed components, along with are subcontracts with Blue Ridge Research and models for predicting aviation noise. specialized data collection programs. Essentially Consulting of Asheville, NC. Sponsor: FAA and Volpe National Transporta- for these experiments laser transducers are used tion Systems Center to detect each encoder strip of a passing reflec- The Propagation and Radiation Group also con- Advisors: A. Atchley, V. Sparrow tive encoder tape. The encoder tape can be tinued its work for the Federal Aviation Admini- mounted directly on the rotating shaft or placed stration through the FAA/NASA/Transport – Kimberly Lefkowitz Riegel, Ph.D. expected fall on a larger diameter hub to increase the pulse Canada PARTNER Center of Excellence 2011 per revolution count of the tape. Transducers (www.partner.aero). One of the ongoing PART Thesis topic: Ray-trace/radiosity methods for

CAV Review ‘10-’11 Technical Group Research Highlights the propagation of sonic booms in urban can- Structural Vibration and Acoustics Student: Peter Romano (MS – Aerospace Engi- yons Steve Hambric, Group Leader neering) Sponsor: NASA [email protected] Advisor: V. Sparrow Title: Energy harvesting for rotorcraft structural The mission of the Structural Vibration and health monitoring applications Sang Cho, Ph.D. expected fall 2011 Acoustics Technical Group is to better under- Sponsor: ARL/Penn State Thesis topic: Sonic boom diffraction around stand the mechanisms of vibration generation PI: Stephen Conlon buildings and hybrid model implementations and propagation in structures and the interaction Student: Mike Quintingeli (MS – Mechanical Sponsor: NASA of structural vibrations with acoustic media, and Engineering) Advisor: V. Sparrow to develop novel methodologies for the analysis, measurement, and control of structural vibra- Title: Non-lethal munitions impact force charac- Brian Tuttle, Ph.D. expected summer 2011 tions and radiated noise. terization Thesis topic: Nonlinear acoustic streaming in Sponsor: Joint Non Lethal Weapons Directorate conical thermoacoustic devices This year, we were visited by PI: Tim McDevitt Sponsor: Office of Naval Research Dr. Liang-Wu Cai, on sabbati- cal from Kansas State Univer- Title: Implementation of a fatigue life protocol sity, who is teaming with us on Sponsor: US Navy Rotorcraft Acoustics and Dynamics a NASA project to use band- PI: Kevin Koudela Ed Smith, group leader gap materials – structures with [email protected] arrays of embedded disconti- Title: Actuator noise characterization calcula- nuities – to minimize transmis- tions The Penn State's CAV Rotorcraft Acoustics and sion noise tones. Liang-Wu gave a talk on his Sponsor: Moog Dynamics Group continues to be at the core of band-gap material research, which is available PI: Rob Campbell our Vertical Lift Research Center. State is home on our CAV lunch seminar online archive. to one of only two Vertical Lift Research Centers Title: Wind-turbine blade vibration calculations of Excellence (VLRCOE) in the country. We were also pleased to wel- Sponsor: Sandia National Lab This Center currently supports nearly 60 full- come our first exchange student PIs: Mike Jonson and John Fahnline time graduate students and involves more than from our international liaison – 25 Penn State faculty members in a wide range INSA de Lyon. Roch Scherrer Title: Characterization of the CAV Reverberant of technologies supporting rotary-wing air- completed his Masters degree Room craft. Seeking cost and weight efficient solu- working in our CAV reverbera- Sponsor: CAV tions to lower interior noise and vibration levels, tion and anechoic rooms, char- PIs: Steve Hambric, Chris Barber, and Steve and reduced exterior noises signatures is a high acterizing the sound transmis- Conlon priority. We have experienced particular sion loss of a composite panel computationally, Student: Andrew Orr (M.S. candidate) growth in programs focused on structural health and experimentally. monitoring, and ultrasonic ice protection sys- Title: Behavior of marine propellers in crashback tems. These areas have "increased the frequency Projects and Graduate Students: conditions range of interest" amongst our CAV Group Title: Fast acoustic boundary element analysis Sponsor: NAVSEA 073R members. Acoustics and dynamics issues asso- on computer clusters PI: Steve Hambric ciated with ducted fan air vehicles, active rotor Sponsor: ARL/Penn State Student: Abe Lee (Ph.D. candidate) systems, and variable speed compound rotor- PIs: John Fahnline craft are driving many of our technical objec- Student: Ken Czuprynski (MS – Computer Engi- Title: Development of Acoustically Tailored tives. Our various research projects are pres- neering) Composite Rotorcraft Fuselage Panels ently supported by the US Army, US Navy, Sponsor: NASA NASA, and the industry sector including large Title: Phononic Crystals and Acoustic Bandgaps PIs: Steve Hambric, Kevin Koudela, and Ed airframe manufacturers, sub-system vendors, and Mirages Smith and numerous small high- technology compa- PI: Tony Jun Huang nies). Emphasis areas include; interactional Student: Sz-Chin Steven Lin (PhD – Engineering Title: Optimization of TBL-excited ribbed air- source noise, acoustical scattering of rotor noise, Science and Mechanics) craft panels to minimize sound radiation ducted fan noise, gearbox noise, actively con- Sponsor: NASA trolled and morphing rotors, active airframe Title: Vibration of coated multilayered plates PIs: Steve Hambric vibration control, crashworthy and impact resis- and shells Student: Micah Shepherd (Ph.D. candidate) tant structures, anti-icing systems, variable Sponsor: NUWC/ONR speed rotors, structural health monitoring, rotor PIs: Sabih Hayek and J.E. Boisvert (NUWC) Title: Acoustics of Shaftless Propulsors loads monitoring, and interior noise control. This Sponsor: DARPA and US Navy year, we were awarded new research programs Title: Nuclear Reactor Vibro-Acoustics PI: Steve Hambric from NASA (partnered with Bell Helicopters), Sponsor: Westinghouse GE (wind turbine ice protection), and the US PI: Peter Lysak and John Fahnline Title: Commercial Nuclear Reactor Flow- Army (airframe crack detection). We continue Induced Vibration and Fatigue Failure to work with Boeing, Sikorsky, Lord Corp, Title: Rotorcraft structural health monitoring Sponsor: Nuclear Regulatory Commission Goodrich. Timken, and several small high-tech using structural intensities PI: Steve Hambric companies in the development of new rotorcraft Sponsor: US Army technologies. PI: Stephen Conlon

Structural Vibration and Acoustics 10

CAV Review ‘10-’11 Technical Group Research Highlights

Underwater Acoustics noise investigations, including field tests and data Chris Barber, group leader analysis to support development of noise models CAV Information [email protected] for maneuvering ships. He is preparing for a June 2011 return to the Navy’s Acoustic Research De- The mission of the Underwater Acoustics Tech- tachment in Bayview, ID, to conduct a follow-up Dr. George A. Lesieutre nical Group is to better understand the propaga- test to last year’s nearfield radiated noise experi- tion of sound in the ocean and the systems with ment, and is also organizing a special session on Director projects in the fields of underwater propagation radiated noise of unmanned underwater vehicles Penn State University and radiation, marine biology, and acoustical for the Nov 2011 ASA meeting in Seattle. 233 Hammond Building oceanography. Brian Fowler (MS Candidate in Acoustics) is University Park, PA 16802 Daniel Park is studying Low Probability of Inter- working on analysis of nearfield radiated noise Tel: 814-865-2569 cept for Sonar applications with an emphasis on data acquired during experiments in 2009 and Fax: 814-865-5965 Covert Detection and Range Estimation. He is 2010 to investigate the effectiveness of beam- also trying to understand covertness itself as formed line arrays for nearfield radiated noise Email: [email protected] characteristic of a system. He is using noise-like measurements in shallow water environments. signals and investigating different types of de- Dr. Steve Hambric tection schemes. Sam Denes (PhD candidate in Acoustics) is start- ing his field work in the Bering Sea examining Associate Director Alex Sell is working on understanding how cer- multi-media sound propagation (water, ice and ARL/Penn State tain shallow water environment features affect air) to develop accurate sonar equation parame- PO Box 30 performance of a model-based Bayesian localiza- ters for the propagation of Pacific walrus vocaliza- tion routine. Also, he is developing a range- tions. This information will be directly related to State College, PA 16804 dependent waveguide invariant distribution, determining the effective range of communication Tel: 814- 863-3030 which utilizes a priori knowledge of the under- between walrus and for management and mitiga- cell: 814- 404-0653 water environment and has applications to local- tion methodologies of this species using passive ization and event recreation. He will present acoustic monitoring. email: [email protected] two papers at the ASA meeting in May. Jennifer Miksis-Olds received funding from ONR Karen J. Thal Chris Applegate is studying various models for to commence a long-term ambient ocean sound predicting attenuation through bubbly liquids. study. This work will use over a decade of data Communication Coordinator He is comparing their accuracy and attempting recorded by the Comprehensive Test Ban Treaty Penn State University to determine the appropriate model to use for a Organization (CTBTO) to investigate patterns of 201 Applied Science Building variety of scenarios. ambient noise level, variability, and its impacts/ implications on ecosystem dynamics in the Pacific University Park, PA 16802 Dale McElhone is modeling acoustic backscatter and Indian Oceans. Tel: 814-865-6364 from bubble distributions. A new effective me- Fax: 814-865-7595 dium approach is being applied for frequencies Email: [email protected] well below the resonant frequency of the bubbles.

Sushma Chandran is studying the literature on cognitive RADAR and looking at how to apply the ideas to SONA/R. She also is analyzing the classification data from an in-water sonar trial and comparing the results to ground truth (i.e. what really happened).

Andrew Pyzdek is looking at how SNR affects the performance of a passive sonar Bayesian localization algorithm. He is using real ocean data from a 1996 measurement. He has prepared a paper for the Seattle ASA meeting in May.

Lee Culver is working on the problem of acoustic propagation through bubbly water, and in particular, how bubble scattering degrades array and the characteristics of bubbles left behind after an underwater explosion. He also is developing an approach to extending the Bayesian localizer to sequential batch processing.

Chris Barber is continuing work on ship radiated