IUTAM-IASS SYMPOSIUM ON DEPLOYABLE STRUCTURES: THEORY AND APPLICATIONS

SOLID MECHANICS AND ITS APPLICATIONS

Volume 80

Series Editor: G.M.L. GLADWELL Department of Civil Engineering University of Waterloo Waterloo, Ontario, Canada N2L 3GI

Aims and Scope of the Series

The fundamental questions arising in mechanics are: Why?, How?, and How much? The aim of this series is to provide lucid accounts written bij authoritative researchers giving vision and insight in answering these questions on the subject of mechanics as it relates to solids.

The scope of the series covers the entire spectrum of solid mechanics. Thus it includes the foundation of mechanics; variational formulations; computational mechanics; statics, kinematics and dynamics of rigid and elastic bodies: vibrations of solids and structures; dynamical systems and chaos; the theories of elasticity, plasticity and viscoelasticity; composite materials; rods, beams, shells and membranes; structural control and stability; soils, rocks and geomechanics; fracture; tribology; experimental mechanics; biomechanics and machine design.

The median level of presentation is the first year graduate student. Some texts are monographs defining the current state of the field; others are accessible to final year undergraduates; but essentially the emphasis is on readability and clarity.

IUTAM-IASS Symposium on Deployable Structures: Theory and Applications Proceedings of the IUTAM Symposium held in Cambridge, U. K., 6-9 September 1998

Edited by

S. Pellegrino University of Cambridge. u.K.

and

S.D. Guest University of Cambridge. u.K.

SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

A C.I.P. Catalogue record for this book is available from the Library of Congress.

ISBN 978-90-481-5539-2 ISBN 978-94-015-9514-8 (eBook) DOI 10.1007/978-94-015-9514-8

Printed on acidlree paper

All Rights Reserved © 2000 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 2000 Softcover reprint of the hardcover 1st edition 2000 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner.

CONTENTS

Preface ....................................................................... ix

List of Participants ........................................................... xi

Opening Address by S. Pellegrino Chainnan of the Scientific Committee ..................................... xv

Opening Remarks by S. Medwadowski President of lASS ...................................................... xvii

Address by R. Wang Representative of IUTAM

Contributed papers

M. AI Khayer and H. Lalvani

XIX

Scissors-Action Deployables Based on Space-Filling Polygonal Hyperboloids ..

M.C. Bailey, T.G. Campbell, D. Brandt, and C. Cassapakis Inflatable Tensioned Membrane Waveguide Antenna Array for Space Applications ................................................... 11

R.J.P. Barker and S.D. Guest Inflatable Triangulated Cylinders .......................................... 17

M. BouderbaIa and R. Motro Folding Tensegrity Systems ............................................... 27

J.H. Brackenbury Wing Folding in Beetles .................................................. 37

A. Britt and H. Lalvani Symmetry as a Basis for Morphological Analysis and Generation of NASA-Type Cubic Deployables ........................................ 45

V.I. Bujakas and A.G. Rybakova High Precision Deployment and Shape Correction of Multi-mirror Space Designs ............................................ 55

C.R. Calladine Deployable Structures: What Can We Learn from Biological Structures? ..... 63

R. Charles Design, Construction and Testing of the Deployable UHF Antenna for SKYNET 4 Stage 2 ................................................... 77

vi

M.A. Crisfield and G. Jelenic Finite Element Analysis and Deployable Structures ......................... 87

M. Ebara and K. Kawaguchi Foldable Rigid Connections .............................................. 97

C.J. Gantes, D.N. Tsouknaki and S.C. Kyritsas Combining Active and Passive Sub-Structures in Snap-Through-Type Deployable Structures .................................................. 107

R. Garcia Dieguez and J.C. Gomez de Cozar Florin system .......................................................... 117

G. Greschik, M.M. Mikulas and R.E. Freeland Scaling of Nonlinear Phenomena with Emphasis on Thin Film Deployable Structures .................................................. 127

F. Haas Wing Folding in Insects: a Natural, Deployable Structure ................... 137

J.D. Hinkle, L.D. Peterson, L.M.R. Hardaway and M.R. Hachkowski Microdynamics of Lightweight Precision Deployable Spacecraft Structures .. 143

K. Iqbal, S. Pellegrino and A. Daton-Lovett Bi-stable Composite Slit Tubes .......................................... 153

J.D. Johnston and E.A. Thornton Thermal-Structural Performance of Rigid Panel Solar Arrays ............... 163

T. Kanemitsu et at. Self-Deployable Antenna Using Centrifugal Force ......................... 173

E. Karni Deployable Swimming Pool Enclosures .................................. 183

K. Kawaguchi A New Approach to Retractable Membrane Structures ..................... 193

F. van Keulen and H. de Boer Accurate Design Sensitivities for Deployable Structures by Exact Differentiation of Rigid-Body Modes ............................ 201

H. Kobayashi, M. Daimaruya and J.F.V. Vincent FoldinglUnfolding Manner of Tree Leaves as a Deployable Structure ........ 211

F. Kovacs Foldable Bar Structures on a Sphere ...................................... 221

B. Kresling Coupled Mechanisms in Biological Deployable Structures .................. 229

vii

x. Liu, C.H. Jenkins, and W.W. Schur Computational Issues in the Modeling of Wrinkling During Parachute Deployment ........................................... 239

M.C. Lou and V.A. Feria Development of Space Inflatable/Rigidizable Structures Technology ......... 251

E. Makai and T. Tarnai Overtonstrained Sliding Mechanisms .................................... 261

F.A. McRobie and J. Lasenby The Kinematics of Large Rotations Using Clifford Algebra ................. 271

J. Mitsugi, K. Ando and Y. Senbokuya A FEM for Complex Deployable Structure Analysis ....................... 281

K. Miura and K. Tanizawa Tension Truss Antenna - Concept, Reality and Future ...................... 291

M. Piekarski Constructional Solutions for Two-Way-Fold-Deployable Space Trusses ...... 301

I. Raskin and J. Roorda Bending of Three-Dimensional Pantographic Column ...................... 311

F.P.J. Rimrott and G. Fritzsche Fundamentals of STEM Mechanics ...................................... 321

F. Scarpa and G. Tomlinson Sandwich Structures with Negative Poisson's Ratio for Deployable Structures 335

M. Schagerl, A. Steindl and H. Troger Dynamical Analysis of the Deployment Process of Tethered Satellite Systems 345

K.A. SetTen, S. Pellegrino and G.T. Parks Deployment of a Panel by Tape-Spring Hinges ............................ 355

V. V. Sidorenko Deployment Dynamics of Flexible Beams ................................ 365

o. Sigmund Systematic Design of Micro and Macro Systems ........................... 373

A. Sogame and H. Furuya Conceptual Study on Cylindrical Deployable Space Structures .............. 383

C.R. Steele and J.P. Fay Inflation of Rolled Tubes ................................................ 393

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W. Szyszkowski and K. Fielden Controlling the Perfonnance and the Deployment Parameters of a Self-Locking Satellite Boom ........................................ 405

B. Tabarrok and K. Behdinan Dynamics of Spacecraft Antenna During Deployment . . . . . . . . . . . . . . . . . . . . .. 415

T. Tanami Tools of Analysis on Mobility and Structural Morphology .................. 425

M. W. Thomson The AstroMesh Deployable Reflector ..................................... 435

V.I. Usiukin Dynamics of Large Deployable Structures ................................ 447

K. Wohlhart Double-Chain Mechanisms .............................................. 457

D. Wright Design, Integration and Testing of an Advanced Synthetic Aperture Radar ... 467

Z. You A New Approach to Design of Retractable Roofs .......................... 477

Closing Session ............................................................. 485

Author Index ............................................................... 491

PREFACE

The IUTAM-IASS Symposium on Deployable Structures: Theory and Applications was held on 6-9 September 1998 in the Department of Engineering, University of Cambridge. The Scientific Committee was appointed jointly by the two sponsoring organisations, the International Union for Theoretical and Applied Mechanics (IUTAM) and the International Association for Shell and Spatial Structures (lASS). Its membership was as follows:

S. Pellegrino (UK, Chairman) L.B. Freund (USA) Y. Hangai (Japan) B. Kroplin (Germany) M.M. Mikulas (USA) F.P.]. Rimrott (Canada)

C.R. Calladine (UK) M. Geradin (Belgium) K. Kawata (Japan) S.]. Medwadowski (USA) A. Samartin Quiroga (Spain) T. Tarnai (Hungary)

The opening lecture of the Symposium was given by Professor C.R. Calladine. It was followed by seven lecture sessions on Concepts, Structural Mechanics, Reflectors, Deployable Structures in Nature, Design and Testing, Inflatable Structures, Simulation, plus a large interactive session during which posters and physical models were shown. A discussion of topics suggested by the participants took place during the closing session. There were 83 participants from 18 countries, and a total of 50 papers were presented.

Financial support was generously provided by the International Union of Theoretical and Applied Mechanics (IUTAM). Additional support was provided by the British Council, the British National Space Centre (BNSC), and Kluwer Academic Publishers.

We thank the members of the Scientific Committee for their willingness to referee to a high standard both the abstracts and the papers for the proceedings. Professor G.M.L. Glad­well, general editor of the Kluwer series on Solid Mechanics and its Applications, carried out a further check of the whole volume; we thank him for finding the time to do this. Members of the Deployable Structures Group at Cambridge assisted in various ways with the organisation of the Symposium; we thank them all. Special thanks are due to Thorsten Hack, who took care of the detailed pre-symposium arrangements. Finally, we thank Drs K. Nederveen and A. Schouwenburg, from Kluwer, and Mrs R. Baxter for help in preparing this volume of proceedings.

It is our hope that these proceedings will prove as enjoyable and stimulating to the reader as the symposium was for all participants. With luck, they will be a lasting contri­bution to the further development of this still young subject.

Simon D. Guest Sergio Pellegrino

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LIST OF PARTICIPANTS

* Denotes a session chairman

Abt, B., Domier Satellitensysteme, D-88039 Friedrichshafen, GERMANY.

Al Khayer, M., School of Architecture, Pratt Institute, 200 Willoughby Ave, Brooklyn NY 11205, USA.

Barrett, R., Composite Optics Inc., 9617 Distribution Ave., San Diego CA 92121, USA.

Bouderbala, M., Ecole D' Architecture Languedoc-Roussillon, 179 Rue de I'Esperou, 34093 Montpellier Cedex 5, FRANCE.

Brackenbury, J., Department of Anatomy, University of Cambridge, Downing Street, Cambridge CB4 5LB, U.K.

Britt, A.L., School of Architecture, Pratt Institute, 200 Willoughby Ave, Brooklyn NY 11205, USA.

Bujakas, V., Astro Space Center of P.N. Lebedev Physical Institute, Profsoiuznaya st. 84/32, Moskow 117810, RUSSIA.

Calladine, C.R., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, U.K.

Charles, R., AEA Technology, Culham, Abingdon OXI4 3DB, U.K.

Clifford, D., Molecular Geodesics Inc., 201 Broadway,3rd. Fl., Cambridge MA 02139-1955, USA.

Crisfield, M., Department of Aeronautics, Imperial College of Science Technology and Medicine, London SW7 2BY, U.K.

Daimaruya, M, Department of Mech. Sys. Engineering., Muroran Institute of Technol­ogy, Mizumoto, Muroran 050-8585, JAPAN.

Danilenko, K.B., Bauman Moscow State Technical University, Prospect Vernasdkogo 113-210, Moscow 117571, RUSSIA.

Daton-Lovett, A., Rolatube Technology, 106 Windmill Road, London TW8 9 NA, U.K.

Durrant, S.J., Fokker Space B.V., P.O. Box 32070, 2303 DB Leiden, NETHERLANDS.

Ebara, M., Ishida Technology Consultants, Toshincho, 50 Komaki-shi, Aichi 485-0028, JAPAN.

Fischer, A., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, U.K.

Furuya, H., Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, JAPAN.

Gantes, C., Department of Civil Engineering, National Technical University of Athens, P.O. Box 31830, GR-10035 Athens, GREECE.

Garcia Dieguez, R., Dpto. Construcciones Arquitectonicas, I. Universidad de Sevilla, Avd. Reina Mercedes 2, 41012 Sevilla, SPAIN.

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Geer, M., British National Space Centre, 151 Buckingham Palace Rd., London SWI W9SS, U.K.

Gomez de Cozar, J.e., Dpto. Construcciones Arquitectonicas, I. Universidad de Sevilla, Avd. Reina Mercedes 2, 41012 Sevilla, SPAIN.

Greschik, G., Center for Aerospace Structures, University of Colorado, Campus Box 429, Boulder CO 80309-0429, USA.

* Guest, S.D., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 IPZ, U.K.

Haas, F., Institut fUr Sportwissenschaft, AG Biomechanik, Seidelstr. 20, D-07749 Jena, GERMANY.

Hack, T., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 IPZ, U.K.

Hanaor, A., National Building Research Inst., The Technion, Haifa 32000, ISRAEL.

Hinkle, J., Center for Aerospace Structures, University of Colorado, Campus Box 429, Boulder CO 80309, USA.

Iqbal, K., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 IPZ, U.K.

Jenkins, C., Department of Mechanical Engineering, South Dakota School of Mines and Technology, Rapid City SD 57701, USA.

Johnston, J.D., Department of Mechanical, Aerospace and Nuclear Engineering, Univer­sity of Virginia, Thornton Hall, Charlottesville VA 22903, USA.

Kanemitsu, T., Seavans-South, Shibaura l-chome, Minato-ku, Tokyo 105-8007, JAPAN.

Karni, E., Faculty of Architecture and Town Planning, Technion-Israel Institute of Tech­nology, Technion City, Haifa 32000, ISRAEL.

Kassabian, P., Flint & Neill Partnership, 21 Dartmouth Street, London SWIH 9BP, U.K.

Kawaguchi, K., Institute oflndustrial Science, University of Tokyo, Roppongi, 7-22-1, Minato-ku, Tokyo 106-8558, JAPAN.

van Keulen, F., Laboratory of Engineering Mechanics, Delft University of Technology, P.O. Box 5033, 2600 CG Delft, NETHERLANDS.

Kimpian, J., Royal College of Art, Kensington Gore, London SW7 2EU, U.K.

Kobayashi, H, Department of Mech. Sys. Engineering., Muroran Institute of Technology, Mizumoto, Muroran 050-8585, JAPAN.

Kovacs, F., Department of Structural Mechanics, Technical University of Budapest, Mii­egyetem rkp. 3, H-1521 Budapest, HUNGARY.

Kresling, B., 170, Rue St Charles, F-750 15 Paris, FRANCE.

* Kroplin, B., Institute for Statics and Dynamics of Aerospace Structures, University of Stuttgart, Pfaffenwaldring 27, 70550 Stuttgart, GERMANY.

Lai, C.-Y., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 IPZ, U.K.

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Langbecker, T., Department of Civil Engineering, University of Queensland, Brisbane QLD 4072, AUSTRALIA.

Leipold, M., DLR, Linder Hoehe, 51147 Kaln, GERMANY.

* Lou, M., Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91107, USA.

McRobie, F.A, Department of Engineering, University of Cambridge, Trumpington Street Cambridge CB2 IPZ, U.K.

Medwadowski, S.J., 5343 Broadway Terrace, Suite no. 205, Oakland, CA 94618, USA.

* Mitsugi, J., NIT Wireless Systems Laboratories, 1-1 Hikarino-oka, Yokosuka 239-0847, JAPAN.

Miura, K., 3-9-7 Tsurukawa, Machida, Tokyo 195-0061, JAPAN.

Motro, R., Ecole d' Architecture Langeudoc-Roussilon, 179 Rue de I'Esperou, 34093 Montpellier, FRANCE.

Nolte, J.F.A., Fokker Space B.V., P.O. Box 32070,2303 DB Leiden, NETHERLANDS.

Pardal, C., School of Architecture, Deu I Mata 152,08029 Barcelona, SPAIN.

Pedretti, M., Passera & Pedretti, Via al Molino Grancia, CH-6916 Graticia, SWITZER­LAND.

* Pellegrino, S., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1 PZ, U.K.

Piekarski, M., Department of Building and Environmental Engineering, Technical Uni­versity of Rzesz6w, AI. Powstanc6w Warszawy 6, 35-959 Rzesz6w, POLAND.

Raskin, I., Department of Civil Engineering, University of Waterloo, Waterloo, Ontario, CANADA N2L 3G 1.

,~ Rimrott, F.P.J., Department of Mechanical and Ind. Engineering, University of Toronto, Toronto, Ontario, CANADA M5S 3G8.

Roorda, J., Department of Civil Engineering, University of Waterloo, Waterloo, Ontario, CANADA N2L 3G I.

Rueckert, G.C., ETH Zurich Institute of Structural Engineering ETH Hoenggerberg, HIL E412, 8093 Zurich, SWITZERLAND.

Scarpa, F., Dynamics Group, Department of Mechanical Engineering, University of Sheffield, Mappin St., Sheffield S I 3JD, U.K.

Schagerl, M., Institut fUr Mechanik, TU-Wien, Wiedner Hauptstr. 8-10/325, A-I040 Wien, AUSTRIA.

Seffen, K.A., Applied Mechanics Division, UMIST, PO Box 88 Manchester M60 1 QD, U.K.

Sidorenko, V., Keldysh Inst. of Applied Mathematics, Miusskaja sq. 4, Moscow 125047, RUSSIA.

Sigmund, 0., Technical University of Denmark, Department of Solid Mechanics, DK-2800 Lyngby, DENMARK.

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Simpson, D., Matra Marconi Space Systems Ltd., Anchorage Road, Portsmouth P03 5PW, U.K.

Smith, T., Composite Optics Inc., 9617 Distribution Ave., San Diego CA 92121, USA.

Sogame, A., Tokyo Institute of Technology, 4259, Nagatsuta, Midori-ku, Yokohama 226-8502, JAPAN.

* Steele, C.R., Department of Aeronautics and Astronautics, Stanford University, Stanford CA 94305-4035, USA.

Surace, C., Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, ITALY.

Szyszkowski, W., University of Saskatchewan, Department of Mechanical Engineering, 57 Campus Drive, Saskatoon, CANADA S7N OWO.

* Tabarrok, B., Department of Mechanical Engineering, University of Victoria, Victoria, BC, CANADA V8W 3P6.

Tan, L.T., Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 IPZ, U.K.

Tanami, T., Center for Space Structures Research, Taiyo Kogyo Corporation, 3-22-1 Higashiyama, Meguro-ku, Tokyo 153-0043, JAPAN.

* Tarnai, T., Department of Structural Mechanics, Technical University of Budapest, Miie­gyetem rkp. 3, H-1521 Budapest, HUNGARY.

Thallemer, A., FESTO AG & Co. Pneumatic Structures, Heugasse 1 D-73728 Esslingen, GERMANY.

Thomson, M.W., Astro Aerospace Corporation, 6384 Via Real, Carpinteria, CA 93013-2920, USA.

Troger, H., Institut fUr Mechanik, TU-Wien, Wiedner Hauptstr. 8-10/325, A-I 040 Wien, AUSTRIA.

Usiukin, V., Bauman Moscow State Technical University, Prospect Vernasdkogo 113-210, Moscow 117571, RUSSIA.

Vincent, J.F.V., Centre for Biomimetics, University of Reading, Reading RG6 6AT, U.K.

Wagner, R., Rosenburstr. 87,70597 Stuttgart, GERMANY.

Wohlhart, K., Institut fUr Mechanik, Technische Universitat Graz, Kopernikusgasse 24, A-8010 Graz, AUSTRIA.

You, Z., Department of Engineering Science, University of Oxford, Parks Road, Oxford OXI 3PJ. U.K.

OPENING ADDRESS by S. Pellegrino

Distinguished Colleagues,

On behalf of the Scientific Committee I declare this IUTAM-IASS Symposium on De­ployable Structures open, and on behalf of the Local Organising Committee I welcome you all.

The idea of holding a meeting on Deployable Structures here at Cambridge was first suggested in 1994 by Dr Medwadowski, President of lASS, at the end of his first visit to our Deployable Structures Laboratory. Since we had all much enjoyed talking to him and found his suggestions on our work very valuable, it seemed natural that we should accept this particular suggestion. Then, Professor Calladine (member of the British delegation of IUTAM) suggested that getting IUTAM involved might help to broaden the scope of the meeting, and I submitted a proposal to this organisation. By August 1996 we had formal approval for the meeting from both organisations, and by October 1996 the Scientific Committee had been formed. From that point on, the organisation of the meeting became a joint effort. The Scientific Committee have been responsible for drawing the list of people to be invited and for reviewing the extended abstracts that were submitted. The response to the invitations that had been sent out far exceeded our expectations, and a fair review process was essential because not all offers could be accepted. So, all proposals were independently reviewed by at least two members of the Scientific Committee. The majority were reviewed by three people, and the standard for acceptance was high.

The Local Organising Committee, and particularly Dr Simon Guest, have worked hard during the last 12 months to make sure that this meeting could happen. I am very grateful to them all. I also wish to thank the British National Space Centre, in London, for providing funds for our Russian colleagues, to encourage ongoing collaborations between the UK and Russia.

Initially, I had expected that about 40 people would participate, but this meeting has turned out to be much larger and we have more than 80 people attending. Also, judging from the booklet of abstracts that has been distributed, the meeting promises to be more diverse and exciting than I could have imagined at the start.

Now, it is up to you all: to the authors of the papers to tell us about their work and to all of the participants to engage in discussions that will stimulate further work. I look forward very much to the busy three days ahead. As well as learning many new things I hope that we will all have fun in the process.

Sergio Pellegrino Chairman of the Scientific Committee

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OPENING REMARKS by the President of lASS

On behalf of the International Association for ShelI and Spatial Structures -IASS- I take great personal pleasure in welcoming alI participants to the Cambridge IUTAM-IASS Symposium on Deployable Structures. At the same time, sadly, I note the absence of Professor Yasuhiko Hangai, who passed away suddenly on August 9 in Tokyo. Yasuhiko Hangai was a briIIiant scientist and engineer, researcher and teacher. Beyond that, he was a wonderful friend and colIeague, always ready to help when help was needed. This year's annual Symposium of the lASS, which wiII be held in Sydney in October, wiII be dedicated to the memory of Yasuhiko Hangai. He wiII be sorely missed.

This Symposium has as its topic deployable structures and, folIowing RusselI, it may be appropriate to consider at the outset what such structures are. A very high-tech, space­oriented structure comes to mind: a sateIIite antenna. After the initial fabrication is completed, it can exist in one of two states: folded and unfolded. The folded state is suited for transportation, but the antenna cannot function as such. The antenna becomes functional only after it takes on the unfolded state, reached from the folded state through some kinetic process of deployment. In principle, this process may be reversible, and many cycles of folding-unfolding might occur. How does an antenna -a deployable structure­differ from a traditional structure, such as the Pantheon in Rome? The Pantheon was built at its final location, and possesses only one possible state of existence, that associated with its function. The Pantheon is not intended to change form; it does not rotate, and its oculus does not become larger or smalIer at will. In the terminology used above in connection with the deployable structure -an antenna, the traditional structure has one state, and one cycle. It seems, however, that there are some historical as welI as modern structures which exhibit some characteristics of deployable systems. A bascule bridge has two states, lifted and normal. A public assembly building with a retractable roof has two possible limiting states, with the roof open or closed, each of them functional. The structure of an optical telescope has an infinite number of possible states, so that it can point at any star location in the sky -the same is true also of the dome which houses the telescope. In the field of aviation, three examples come to mind. A carrier plane has two states: wings folded or unfolded. A sailplane also has two states, disassembled for transport, or assembled and capable of flight. An air inflatable plane, first built in England in the thirties, is another example.

A particularly interesting example is afforded by the Mongolian yurta. Folded, it was loaded on a pack animal and transported to a new location. Unfolded, it served then as a shelter. Two states, many cycles. Tents, historical and modern, have similar characteristics.

FinalIy, prefabricated structures of different types might be considered as belonging to the class of deployable structures, although this may not be as cut and dry as in some other cases.

Thus, the field seems very large, and deserves the kind of attention that it wiII receive at this Symposium. I am confident, that the presentations and discussions offered here will contribute significantly to the progress in the design of deployable structures. I am also convinced that the Proceedings of this Symposium will become indispensable to alI

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workers in the field, as well as to all those wishing to become acquainted with it.

In closing, I wish to acknowledge a number of institutions and individuals who con­tributed significantly to the successful organization of this Symposium. I am appreciative of IUTAM's agreement to co-sponsor the Symposium with lASS. Thanks are due the Department of Engineering, University of Cambridge for offering to organize and host the Symposium. Professor Calladine's steadfast support and active participation are very much appreciated. It is a most pleasant duty to acknowledge the effective efforts of Dr Simon Guest and members of the Organizing Committee. Finally, last but distinctly not least, I wish to express my appreciation to Dr Sergio Pellegrino, the heart and soul of this venture. His leadership and organizational skills were indispensable factors in making the Symposium a success.

Stefan 1. Medwadowski President lASS

ADDRESS by the IUTAM Representative I

Ladies and Gentlemen, Dear colleagues,

I represent Professor Werner Schiehlen, president of IUTAM (International Union of The­oretical and Applied Mechanics). On his behalf, I wish to sincerely congratulate the organizers of this Symposium and to express a very wann welcome to our colleagues coming from different parts of the world.

The Symposium was first proposed by the Cambridge group headed by Dr Pellegrino. It was approved by the General Assembly of IUTAM in August, 1996 and the scientific committee was appointed by IUTAM and lASS. The subject of deployable structures has come to such a stage that further interaction with the theoretical and applied mechanics communities is needed in developing new generic solutions and in understanding the underlying principles of the solutions that already exist. It is a cross-disciplinary field, but so far contacts between different disciplines have been limited. This joint symposium sponsored by IUTAM and lASS aims to serve this purpose. It is a policy of IUTAM to encourage interaction with other related unions and societies for the promotion of science and technology. To hold joint symposia on subjects of mutual interest is a very effective way for such interaction. We wish the symposium to be a success and that such cooperative effort will prevail in the future.

Let me now give an introduction to the objects of IUTAM and a brief sketch of her history. IUTAM is an international non-governmental organization whose objects are as follows: to form a link between persons and organizations engaged in scientific work in theoretical and applied mechanics or in related sciences; to organize international con­gresses and other international meetings for subjects falling within the field of mechanics; to engage in other activities intended to promote development of mechanics, both theoret­ical and applied, as a branch of science.

Shortly after the first world war which had interrupted the long existing contacts be­tween scholars and scientists, Theodore von Karman and Tullio Levi-Civita initiated a meeting in Innsbrock, Austria, I 922, on hydro- and aero-mechanics. The great success of that meeting inspired J.B. Burgers to suggest to von Karman that a larger conference be organized, embracing the entire field of applied mechanics. This resulted in the First International Congress of Applied Mechanics (ICAM) held in 1924 at Delft, Holland. Its tremendous success led to the creation of a permanent institution, the International Congress of Applied Mechanics. The following congresses were the 2nd at Zurich (1926), the 3rd at Stockholm (1930), the 4th at Cambridge, England (1934), the 5th at Cambridge, Massachusetts (1938). The next one was planned to be held at Paris in 1942, but was disrupted by the war.

After the war, ICSU (International Council of Scientific Unions) was created to coordi­nate the activities of different unions with the United Nations Educational, Scientific and Cultural Organization (UNESCO). At the 6th Congress of Applied Mechanics in Paris, IU­TAM was created and in 1947 admitted to ICSU. Further Congresses were held in London

I Professor Wang was unable to deliver his address, which was read by Professor Rimrott.

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(1948), Istanbul (1952), Brussels (1956), Stresa (1960), Munich (1964), Stanford (1968), Moscow (1972) -the title of the congress had changed to ICTAM, Delft (1976), Toronto (1980), Lyngby (1984), Grenoble (1988), Haifa (1992), and Kyoto (1996). The next one is scheduled for August 2000, in Chicago.

The Union is formed by national organizations active in scientific work in theoretical and applied mechanics; at present there are 47 of such national adhering organizations. In 1970 the General Assembly also created the possibility for other international organizations engaged in scientific work closely related to that of our union to become affiliated to IUTAM. Since then 14 organizations have been accepted as affiliated members.

With the support of UNESCO, meetings in between Congresses were made possible, the first IUTAM Symposium was held in 1949, after which 2-3 symposia were held each year for several years. This number has now increased to about 8-9 symposia each year, half of which are in fluid mechanics and half in solid mechanics. These symposia have been reserved for invited scientists only. This has made it possible to limit the size of the symposia to ensure efficient work and vivid discussion. The more recent IUTAM Symposia which may be of interest to the participants here are the symposium on Unilateral Multibody Dynamics held in Munich a month ago and the symposium on advanced Optical Methods and Applications in Solid Mechanics held in Poi tiers, France last week. Details of these and future symposia, as well as the next Congress in 2000 (Chicago) can be found on the IUTAM web site (http://www.iutam.org).

Finally, I would like to thank again the Organizing Committee, chaired by Dr Pelle­grino, and the University of Cambridge for their excellent work and the provision of such a magnificent place for the meeting.

Ren Wang