Sandwich Structures 7: Advancing with Sandwich

SANDWICH STRUCTURES 7: ADVANCINGWITH SANDWICH STRUCTURES AND MATERIALS Sandwich Structures 7: Advancing with Sandwich Structures and Materials Proceedings of the 7th International Conference on Sandwich Structures, Aalborg University, Aalborg, Denmark, 29-31 August 2005

Edited by

O.T. THOMSEN Aalborg University, Aalborg, Denmark

E. BOZHEVOLNAYA Aalborg University, Aalborg, Denmark and

A. LYCKEGAARD Aalborg University, Aalborg, Denmark A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN-10 1-4020-3444-X (HB) ISBN-13 978-1-4020-3444-2 (HB) ISBN-10 1-4020-3848-8 (e-book) ISBN-13 978-1-4020-3848-8 (e-book)

Published by Springer, P.O. Box 17, 3300 AA Dordrecht, The Netherlands. www.springeronline.com

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The cover depicts the ICSS-7 logo, by Kjeld Moseholm and Anders Lyckegaard. © Institute of Mechanical Engineering, Aalborg University, Denmark. Used by permission.

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Printed in the Netherlands. TABLE OF CONTENTS

Preface xvii

KEYNOTE LECTURES

Sandwich structures: Past, present, andfuture 3 J.R. Vinson

Sandwich structures technology in commercial aviation 13 A.S. Herrmann, P.C. Zahlen and I. Zuardy

Damage assessment and damage tolerance of FRP sandwich structures 27 B. Hayman

SESSIONSORGANISED BY THE ONR (Ofﬁce of Naval Research, U.S. Navy, Program Manager Dr. Y. Rajapakse)

Mechanics & Analysis

Geometrical non-linear response of modern sandwich panels – Localized effects 47 Y. Frostig

Global buckling of wide sandwich panels with orthotropic phases: An elasticity solution 57 G.A. Kardomateas

Parametric study of structurallygraded core junctions 67 A. Lyckegaard, E. Bozhevolnaya and O.T. Thomsen

Local effects induced by core junctions in sandwich beams under general loading conditions 77 E. Bozhevolnaya, A. Lyckegaard and O.T. Thomsen

v vi Table of Contents

Material characterization of PVC foam under staticanddynamic loading 87 D.C. Loup, R.C. Matteson and A.W.J. Gielen

Dynamics

Dynamic response of anisotropic sandwich panelstounderwater and in-airexplosions 97 L.Librescu, S.-Y. Oh and J. Hohe

Enhancement of blast resistance of sandwich plates 107 G.J. Dvorak and Y.A. Bahei-El-Din

Failure, Fracture, Damage and Fatigue

A two-propertyyield, failure (fracture) criterion for isotropic matrix materials 117 R.M. Christensen

On crack extension in foam cored sandwich fracture specimens 121 R.C. Matteson, L.A. Carlsson, F. Aviles and D.C. Loup

Effect of geometric constraint on fracture toughness of PVC foam core sandwichbeams 131 K. Shivakumar, H. Chen and A. Bhargava

Damage evaluation of sandwich structures using vibration and thermal signatures 143 A. Cecchini, F. Just-Agosto, D. Serrano and B. Shaﬁq

Fatigue performance and size effects in sandwich composites 153 B. Shaﬁq, A. Quispitupa, F. Just and M. Banos

Study of fatigue endurance of conventional and modiﬁed core junctions in sandwich beams 161 E. Bozhevolnaya, A. Lyckegaard and O.T. Thomsen

Fatigue of closed cell foams 171 D.Zenkert, A. Shipshaand M. Burman Table of Contents vii

Fatigue of pure and nanophased sandwich composites under shear loading 183 H.Mahfuz, S. Zainuddin, M.F. Uddin, V.K. Rangari and S. Jeelani

Environmental Degradation

Sea water effects on polymeric foams and their sandwichlay-ups 193 Y.J. Weitsman, X. Li and A. Ionita

MODELLING, ANALYSIS AND DESIGN

Sandwich plates: Stresses, deﬂection, buckling and wrinkling loads 201 H.-R. Meyer-Piening

Modelling of viscoelastically damped sandwich beams: A comparative study 211 H. Hu, S. Belouettar, E. Daya and M. Potier-Ferry

A homogenization based theory for laminated and sandwich beams 221 J.S. Hansen, G. Kennedy and S.F.M. de Almeida

Modelling of composite and sandwich plates by a trigonometric layerwise theory and multiquadrics 231 C.M.C. Roque, A.J.M. Ferreira and R.M.N. Jorge

Stabilitybehaviour of cylindrical and conical sandwich shellswith ﬂexible core 241 C. Zhong and H.-G. Reimerdes

High order nonlinear contact effects in the dynamic behavior of delaminated sandwich panels with a ﬂexible core 251 H. Schwarts-Givli, O. Rabinovitch and Y. Frostig

Bending behavior of sandwich panels with a “soft” core and embedded rigid inserts 261 O. Rabinovitch and E. Hamed

Elastic behaviour of Zreinforced sandwichbeams 271 M. Leite, A. Silva and M. Freitas viii Table of Contents

Wrinkling of shallow sandwich shells for the general case of multi-axial orthotropy, curvature andloading 281 V. Skvortsov andO.T. Thomsen

Transverse stresses of a ﬁller under multipoint loading of a sandwich panel 291 V.A. Polyakov, R.P. Shlitsa, V.V. Khitrov and V. I. Z higun

A triangular ﬁnite element for sandwich plates accounting for transverse core compressibility 301 S. Demiray, W. Becker and J. Hohe

Finite element for the static and stability analysis of sandwich plates 311 M.Linke, W. Wohlers and H.-G. Reimerdes

Two FE formulations for a rapid 3D stress analysis of composite sandwich structures 321 A. Wetzel and L. Kärger

Sandwich materials selection charts 331 J. Pﬂug and I. Verpoest

Optimal design of laminated extended & honeycomb cores sandwich panelsunder out-of-plane load with simply supportedboundary conditions usinggeneticalgorithm 341 M.J. Jamali, I. Rajabiand M.H. Kadivar

Designing sandwichinserts and core junctions for maximum structural stiffness usingdiscrete material optimization 351 J. Stegmann and E. Lund

FRACTURE AND DAMAGE TOLERANCE

On residual compressive strength prediction of composite sandwich panels after low-velocity impact damage363 Z. Xie, A.J. Vizzini and M. Yang

Investigation of parameters dictating damage and energy adsorption characteristics in sandwich panels 373 G.Zhou, M. Hill and N. Hookham Table of Contents ix

Real-time damage detection ofhoneycomb sandwich structures using small-diameter ﬁber Bragg grating sensors 383 S.Minakuchi, Y. Okabeand N. Takeda

The inﬂuence offace sheet wrinkle defects on the performance of FRP sandwich structures 393 B.Hayman, C. Berggreen and R. Pettersson

Residual strength ofdebonded sandwich panels loaded withlateral pressure 403 P. Jolma, S. Segercrantz and C. Berggreen

Measurement of interface fracture toughness of sandwich structures 413 R.C. Østergaard and B.F. Sørensen

Numerical study of fractured sandwich composites under ﬂexural loading 423 E.E. Theotokoglou, L.A. Carlsson, C.D. Vrettos and H. Mahfuz

Dependence of sandwich damage initiation and crack propagation on core material fracture properties 433 L. Berger, M. Morgenthaler, W. Cantwell, K. Feichtinger and R. Elkin

Dependence ofinplane sandwich shear deformation on core material type and thickness 441 M. Morgenthaler, L. Berger, K. Feichtinger and R. Elkin

Residual strength of in-plane loaded debonded sandwich panels. Experimental investigation 451 C. Lundsgaard-Larsen, C. Berggreen and A. Nøkkentved

Residual strength of in-plane loaded debonded sandwich panels. Fracture mechanical modelling 461 C. Berggreen and B.C. Simonsen

Resistance of fastenings of sandwich panels 471 P. H assinen x Table of Contents

Experimentalfailure mode determination of GRP/PVC-foam sandwich T-joints 477 A.W.J. Gielen, W. Trouwborst and D.C. Loup

Flexuralbehaviour of aluminium foam/composite structures 487 M.Styles, P. Compston and S. Kalyanasundaram

Repairclassiﬁcation for sandwich panelswithhail damage 497 M.Das,E.Madenci and H. Razi

Damage tolerance assessment of repaired composite sandwich structures 507 R. Trask, B. Cripps and A. Shenoi

DYNAMICS, VIBRATION AND SOUND

Dynamical transient response of shallow sandwich panel subjected to pressure ﬁeld 519 S. Kadyrov and V. Skvortsov

Effect of transverse core compressibility on dynamic buckling of sandwich structures 527 J. Hohe, L. Librescu and S.Y. Oh

Dynamiccharacterisation of marine sandwich structures 537 M.Battley, I. Stenius, J. Breder and S. Edinger

Local free vibration analysis of initially stressed curved sandwich beam 547 W. Wang and R.A. Shenoi

Vibration analysis of composite sandwich plates and layup optimization 557 H. Sekine, H. Shirahata and M. Matsuda

Flexural vibrations of a three-layer sandwich beam 567 D. Backström and A. Nilsson

Aneffective 2D linear elasticity vibrational modelfor layered and sandwich clamped-clamped unidirectional strips 577 S. Karczmarzyk Table of Contents xi

Minimization of acoustic radiation from composite sandwich structures 587 H.Denliand J.Q. Sun

On wave propagation in sandwich plates under heavy ﬂuid loading 597 S. Sorokin and N. Peake

Wave propagation in a sandwich plate loadedbyaviscous compressible ﬂuid 605 A.V. Chubinskiy and S.V. Sorokin

IMPACT

Impact damageonlightweight sandwich panels 615 D. Zhou and W.J. Stronge

Ballistic resistance of 2D & 3D woven sandwich composites 625 A. Shukla, J. Grogan, S.A. Tekalur, A. Bogdanovich and R.A. Coffelt

Impact and indentation behavior of sandwich panels 635 C.-J. Lindholm

A comparison of low energy impact behaviour in aluminium foam and polymer foam sandwich structures 643 P. Compston, M. Styles and S. Kalyanasundaram

Numerical modeling of sandwich panel response to ballistic loading 653 J. Kepler and M.R. Hansen

Low velocity impact investigations of sandwich panels with different cores 661 W. Göttner and H.-G. Reimerdes

Mechanical behavior of rubber-ﬁlled multifunctional honeycomb sandwich composite 671 H.Hao, C.-R. Joe and D.-U. Kim

Stitching effect on static and dynamic behaviour of sandwich structures 681 B. Lascoup, Z. Aboura, K. Khellil and M. Benzeggagh xii Table of Contents

PROCESSING AND FABRICATION

Continuous manufacturing and performance of 3D reinforced sandwich structures 693 G.LeRoy, C. Binetruy and P. Krawczak

A novel extrusion-welded sandwich structure for thermoplastic composite storagetanks 703 E. Lagardere, M.-F. Lacrampe, O. Skawinski, P. Krawczak,C.Ducret and M. Giletti

The opportunities ofﬂexible foam processing for rigid foam sandwich cores 713 H. Mispreuve and L. den Haan

Formability oflightweight, vibration damping and medium perfused sandwich sheets 723 R. Kopp, M. Nutzmann and J. van Santen

Fabrication and mechanical properties offunctionally graded micro porous metals byMIM-base powder space holder method 733 K. Nishiyabu, S. Matsuzakiand S. Tanaka

Sandwich injection moulding and physical properties of cup-stacked carbon nanotube/polypropylene and polypropylene 743 K. Okubu, S. Tanaka, N. Oya, K. Nishiyabu, T. Yanagisawa and M. Tomita

New ROHACELL development for resin infusion processes 753 J. Scherble and T. Jahn

Development and validation of a continuous production conceptfor thermoplastic honeycomb 763 J.P. Bratﬁsch, D. Vandepitte, J. Pﬂug and I. Verpoest

Sandwich panel with a periodical and graded core 773 J. Nygaard, A. Lyckegaard and J. Christiansen

Investigation of the cure process for thick composite sandwich panels783 D.K. Jensen Table of Contents xiii

NDE AND ENVIRONMENTAL DEGRADATION

Automated ultrasonic inspection of large-scale sandwich structures 795 T.M. Wulf

Evaluation of sandwich materialsusing ultrasonicair-coupled scanning technique 805 K.K. Borum

Structural NDE of CFRP composite materialsusing Fiber Bragg Grating sensors 815 J. Leng, Y. Liu, X. Xu and S. Du

Studyof the hygro-mechanicalbehavior of corrugated cardboard 823 S.Allaoui, Z. Aboura and M. Benzeggagh

NEW MATERIALS AND MATERIALS CHARACTERISATION

New concepts for sandwich structures 835 J.L. Grenestedt

Magnesium integral foam – A new metallic sandwich structure 845 M.Hirschmann, C. Körner and R.F. Singer

New improved foam core materials for advanced processing 855 S. Reuterlöv

Characterisation of novel K-cor sandwich structures 865 P. Casari, D. Cartié and P. Davies

Finite element analysis on out-of-plane compression properties of thermoplastic honeycomb 875 X. Fan, I. Verpoest and D. Vandepitte

Deformation of foam cores in uniaxial compression-tension cycle 885 V. Koissin and A. Shipsha

Loading rate effects on foam cores for marine sandwich structures 895 E. Lolive, P. Casari and P. Davies xiv Table of Contents

Characterization of thethermal expansion behaviour of aPVCfoam core: Non-linearities and gradients across thewidth 905 P. Casari, C. Ferreira and F. Jacquemin

Determination ofin-plane and out-of-plane elastic constants for medium-thickness sandwich composite skins 915 H.Toftegaard and S. Goutianos

Stochastic homogenization of polymeric foams 925 J. Hohe

Stochastic ﬁnite element models of foam materials 935 S. Hallström and S. Ribeiro-Ayeh

APPLICATIONS AND DESIGN SOLUTIONS

Application of load carrying sandwich elements in largewind turbineblades 947 J.F. Jensen, J.P. Schultz, C. Berggreen and K. Branner

Thermoplastic composite sandwich structure for sportive applications 957 M.M. Sommer, M. Päßler, R. Schledjewski and M. Stack

Study of snowboard sandwich structures 967 C.Borsellino, L. Calabrese, R. Passari and A. Valenza

Development and evaluation of an RTM bicycle frame 977 N.G. Pantelelis

Development of new reinforced load introductions for sandwich structures 987 M.A. Roth

Sandwich structures with composite inserts: Experimental studies 997 G. Nageswara Rao, U. Agrawal and N.K. Naik

Development and evaluation of FRP sandwich beams containingglass ﬁbers into phenolic foam core 1007 G.Ben,A.Shoji and M. Souma Table of Contents xv

Experimental and numerical analysisofhollow andfoam-ﬁlled A-stringer/A-former under axial compression load andbending moment 1017 R.Krämerand M.A. Roth

Author Index 1027

Subject Index 1031 PREFACE

This publication contains the printed version of thescientiﬁc articles presented at the7th International Conference on Sandwich Structures (ICSS-7). The conference was organisedbythe Institute of Mechanical Engineering of Aalborg University, Aalborg, Denmark,totakeplace at Aalborg University on 29–31 August 2005. Previous conferences inthis series were held at theRoyal Institute of Technology (KTH), Stockholm, Sweden, in 1989; theUniversity of Florida, Gainesville, Florida, in 1992; Southampton University, Southampton, U.K., in 1995; the Royal Institute of Technology (KTH), Stockholm, Sweden, in 1998; theFederal Institute of Technology (ETH), Zurich,Switzerland, in 2001; and in Ft. Lauderdale, Florida, in 2003. Over the last years the science and technology of sandwich structures and materials has gained an impressive momentum, and the use of sandwich structures and materials in a large variety of products covering the range from sport- inggoods to satellites is on the increase. The overall objective of this conference (ICSS-7) is to provide a forum for the presentation and discussion of the latest research and technology on all aspects of sandwich structures and materials, spanning the entire spectrum of research to applications in many ﬁelds including aircraft, spacecraft, train and automotive applications, wind turbine blades, boat/ship hulls and superstruc- tures and many others. Looking towards the future, all forecasts show that the use of sandwich structures technology will increase even further, as this will provide many op- tions for the effective design of affordable, reliable, and durable structures with multifunctional capabilities. The ICSS-7 andfuture conferences inthis series will play an important role inthis, and provideaforum for discussion and ex- changeof the latest research,aswell as to act as an incubator and source of inspiration for further developments.

Technical Programme The presentations and the papers at the ICSS-7 are groupedinto severalbroad areas, including: Modelling, analysisanddesign; Fracture anddamage tol-

xvii xviii Preface erance; Dynamics, vibration and sound; Impact and energy absorption; Pro- cessing andfabrication; NDE and environmentaldegradation; New materials and materialscharacterisation, Applications anddesign solutions. Thetechnical program of the conference consists of the presentation of 102 scientific papers in 3 parallel sessions. The truly international nature of the ICSS-7 is highlightedbythe fact, that the authors of the presentations repres- ent 30 countries from the 5 continents Asia, Europe, North America, South America andOceania. The ICSS-7 technical program includes 3 keynote lectures, one each morn- ing of the days of the conference. The first, presented by Professor, Ph.D. Jack Vinson, University of Delaware, Delaware, USA, is entitled “Sandwich structures – Past, present and future”, and addresses the technical aspects of sandwich materials and structures technology in a historical perspective. The second keynote lecture, presented by Professor, Dr. Axel Herrmann, Air- bus, Composite Technology Center, Stade, Germany, is entitled “Sandwich structures technology in commercial aviation – Present applications and future trends”, and addresses the state of the arts and future directions of sandwich structures technology in civil aviation. Finally, the third keynote lecture, given by Dr. Brian Hayman, of “Det Norske Veritas” (DNV), Norway, is entitled “Damage assessment and damage tolerance of FRP sandwich structures”, and addresses the very important topics of damage assessment and damage tolerance in sandwich structures. Included in the conference are also 4 special sessions with a total of 16 presentations organisedbythe U.S. Navy,Office of Naval Research (ONR, Program Manager Dr. Y. Rajapakse). These special sessions present research of specialinterest to navy applications of sandwich structures, and sponsored entirely or inpart by the ONR.

Acknowledgements Theorganisers of this conference wish to acknowledge the contributions of themembers of the international scientificand organising committee (listed onthe following page) towardsthe success of the ICSS-7. Theirsignificant help inreviewing and selecting the contributions for the conference has made it possible to ensure a very high scientific standard. The sponsors of the conference (listed on the following page) are also thanked duly for their belief in the necessity of this professional gathering and their generous financial and moral support. The support received for the general cost associated with the ICSS-7, as well as to social events throughout the conference days, has made it possible to keep the conference registration fee at a reasonable level. In addition, the support of the sponsors has made it possible to invite the keynote lecturers, and to support the attendance of Preface xix researchers from countries where the financial situation would otherwise not haveallowed this. Theorganisers of the ICSS-7 would likealso to acknowledge and thank Springer, thepublisher of the conference proceedings (in particular Nathalie Jacobsand Anneke Pot), and Jolanda Karada (KaradaPublishing Services) for theirpatience and professionalism in preparing theprinted proceedings.

OleThyboThomsen Elena Bozhevolnaya Anders Lyckegaard Aalborg University,10May 2005

International Organising and Scientiﬁc Committee Dr. Mark Battley, Industrial Research Limited,NewZealand Professor ChristopheBinetruy, Ecole des Mines de Douai, France Dr. Antonio Ferreira, University of Porto, Portugal Professor Yeoshua Frostig, Technion, Israel Dr. Brian Hayman, DNV, Norway Professor Axel Herrmann, Airbus, CTC GmbH, Germany Mr. Gunnar Holm, VTT, Finland Professor George Kardomateas, Georgia Institute of Technology, U.S.A. Professor Hans-Reinhard Meyer-Piening, ETH, Switzerland Dr. Yapa Rajapakse, Ofﬁce of Naval Research, U.S.A. Professor Bhavani Sankar, University of Florida, U.S.A. Professor R. AjitShenoi,University of Southampton, U.K. Professor VitalySkvortsov, St. Petersburg State Marine University, Russia Dr. AloisStarlinger, Stadler AltenrheinAG,Switzerland Professor C. T. Sun, Purdue University, U.S.A. Professor Roberto Teti,University of Naples, Italy Professor Jack R. Vinson, University of Delaware, U.S.A. Professor Dan Zenkert, Royal Institute of Technology (KTH), Sweden

Sponsors Primary Sponsors:

TheObel Family Foundation, Aalborg, Denmark (www.obel.com) TheOfﬁce of Naval Research, MaterialsS&TDivision (ONR 332), Arlington, Virginia, U.S.A. (http://www.onr.navy.mil/sci tech/engineering/332 materials) Dr. Yapa D.S. Rajapakse, Program Manager, Solid Mechanics xx Preface

Degussa, RöhmGmbH & Co. KG, Germany (www.rohacell.com) Alcan Airex AG, Switzerland (www.alcanairex.com & www.alcancomposites.com)

Sponsors:

LM Glasﬁber A/S, Denmark (www.lmglasﬁber.com) TheDanish Plastics Federation, Division of Composite Materials (www.plastics.dk) Institute of Mechanical Engineering, Aalborg University (www.ime.aau.dk) Faculty of Engineering and Science, Aalborg University (www.aau.dk)

Main Event Sponsor:

DIAB Group International (www.diabgroup.com)

Professional Society Sponsorship and Endorsers:

The European Society for Composite Materials (ESCM) The Danish Society of Mechanical Engineers under the Danish Society of Engineers (www.ida.dk) Springer (www.springeronline.com) KEYNOTE LECTURES