COMPOSITE STRUCTURES

Proceedings of the 1st International Conference on Composite Structures, held at Paisley College of Technology, Scotland,from 16 to 18 September 1981, organised in association with the Institution of Mechanical Engineers

and the National Engineering Laboratory.

COMPOSITE STRUCTURES

Edited by

I. H. MARSHALL

Department of Mechanical and Production Engineering, Paisley College of Technology, Scotland

APPLIED SCIENCE PUBLISHERS LONDON and NEW JERSEY

APPLIED SCIENCE PUBLISHERS LTD Ripple Road, Barking, Essex, England

APPLIED SCIENCE PUBLISHERS INC. Englewood, New Jersey 07631, .uSA

British Library Cataloguing in Publication Data

International Conference on Composite Structures (lsI: 1981: Paisley College of Technology) Composite structures. I. Composite materials--Congresses 2. Composite constructions-Congresses I. Title II. Marshall, I. H. III. Institution of Mechanical Engineers IV. National Engineering Laboratory 624.1'8 TA664

ISBN-13: 978-94-009-8122-5 DOl: 10.1007/978-94-009-8120-1

e-ISBN-13: 978-94-009-8120-1

WITH 74 TABLES AND 362 ILLUSTRATIONS

© APPLIED SCIENCE PUBLISHERS LTD 1981

Softcover reprint of the of the hardcover 1st edition 1981

The selection and presentation of material and the opinions expressed in this publication are the sole responsibility of the authors concerned.

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers, Applied Science Publishers Ltd,

Ripple Road, Barking, Essex, England

Preface

The papers contained herein were presented at the First International Conference on Composite Structures held at Paisley College of Technology, Paisley, Scotland, in September 1981. This conference was organised and sponsored by Paisley College of Technology in association with The Institution of Mechanical Engineers and The National Engineering Laboratory (UK).

There can be little doubt that, within engineering circles, the use of composite materials has revolutionised traditional design concepts. The ability to tailor-make a material to suit prevailing environmental conditions whilst maintaining adequate reinforcement to withstand applied loading is unquestionably an attractive proposition. Significant weight savings can also be achieved by virtue of the high strength-to-weight and stiffness-to-weight characteristics of, for example, fibrous forms of composite materials. Such savings are clearly of paramount importance in transportation engineering and in particular aircraft and aerospace applications.

Along with this considerable structural potential the engineer must accept an increased complexity of analysis. All too often in the past this has dissuaded the designer from considering composite materials as a viable, or indeed better, alternative to traditional engineering materials. Inherent prejudices within the engineering profession have also contributed, in no small way, to a certain wariness in appreciating the merits of composites.

However, the potential benefits of composite materials are inescapable. The last two decades have seen a phenomenal increase in the use of composites in virtually every area of engineering, from the high technology

v

vi Preface

aerospace application to the less demanding structural cladding situation. Research and development in this field have been unparalleled in history with the rate of advance of knowledge seeming to increase daily. Such advances can only be fully utilised if shared and discussed with others who have similar interests. With this in mind, and with a conscious need for dissemination of knowledge between users, manufacturers, designers and researchers involved in structures manufactured using composite materials, the present international conference was organised.

Authors from thirteen countries combine with delegates from virtually every major industrial nation in the world to make this a truly international gathering of specialists in an ever-expanding technology. Topics under discussion range from the possible uses of natural fibre composites to precision fabrication techniques employed in the space shuttle programme, each contribution relating to a particular aspect of composite structural engineering.

An international conference can only succeed in making a contribution to knowledge through the considerable efforts of a number of enthusiastic and willing individuals. In particular, thanks are due to the following:

The Conference Steering Committee Professor J. Anderson Paisley College of Technology

(Chairman) Dr W. S. Carswell Dr J. Rhodes C. I. Phillips J. A. Wylie

Dr E. J. Smith

National Engineering Laboratory University of Strathclyde Scott Bader Co. Ltd Centre for Liaison with Industry and Commerce, Paisley College of Technology Pilkington Brothers Ltd

The International Advisory Panel L. N. Phillips, OBE Royal Aircraft Establishment (UK) Professor R. M. Jones Institute of Technology, Southern Methodist

Dr A. R. Bunsell Professor S. W. Tsai Dr W. M. Banks Dr C. Patterson

Dr E. Anderson

University, Dallas (USA) Ecole des Mines de Paris (France) Air Force Materials Laboratory, Ohio (USA) University of Strathclyde (UK) Institute of Physics, Stress Analysis Group (UK) Battelle Laboratories, Geneva (Switzerland)

Preface

The Local Organising Committee G. Macaulay 1. S. Paul 1. Kirk F. A. Allen The Conference Secretary, Mrs C. MacDonald

vii

We are also grateful to many other individuals who contributed to the success of this event. A final thanks to Nan and Simon for their support during the conference.

I. H. MARSHALL

Contents

Preface ...................................................................................... v

Session I: Plenary (Chairman: T. C. DOWNIE, Paisley College of Technology, Scotland)

1. Composite Materials Education in the United States ........ . R. M. JONES (Southern Methodist University, Dallas, USA)

2. Engineering Plastics-Some Factors Affecting Technology Transfer ............................................................................. 16

J. HUMPHREYS (Pilkington Brothers Ltd, Ormskirk, England)

Session II: Bolted Connections (Chairman: W. S. CARSWELL, National Engineering Laboratory, East

Kilbride, Scotland)

3. Analysis of the Shearout Failure Mode in Composite Bolted Joints ................................................................................. 34

D. W. WILSON and R. BYRON PIPES (Center for Composite Materials, University of Delaware, Newark, USA)

4. Stress an<\. Strength Analysis of Bolted Joints in Composite Laminates ........................................................................... 50

S. R. SONI (Universal Energy Systems, Inc., Dayton, USA) ix

x Contents

5. Some Environmental and Geometric Effects on the Static Strength of Graphite Cloth Epoxy Bolted Joints ................ 63

J.A. BAILIE, L. M. FISHER, S.A. HOWARD and K. G. PERRY (Lockheed Missiles & Space Co. Inc., Sunnyvale, USA)

Session III: Environmental Effects (Chairman: S. W. TSAI, Air Force Materials Laboratory, Ohio, USA)

6. The Stress-Rupture Behaviour of GRP Laminates in Aqueous Environments ..................................................................... 79

R. C. WYATT (CEGB, Bristol, England), L. S. NORWOOD (Scott Bader Co. Ltd, Wellingborough, England) and M. G. PHILLIPS (University of Bath, England)

7. Water Absorption by Glass Fibre Reinforced Epoxy Resin 92 P. BONNIAU and A. R. BUNSELL (Ecole des Mines de Paris, France)

8. Failure of GRP in Corrosive Environments ....................... 106 P. J. HOGG, D. HULL and M. J. LEGG (University of Liverpool, England)

Session IV: Research and Development: Analytical Studies (Chairman: I. H. MARSHALL, Paisley College of Technology, Scotland)

9. Large Deflection Analysis of Bimodular Cross-Ply Strips ... 123 G. J. TURVEY (University of Lancaster, England)

roo Analysis of Thermally Stressed Variable Thickness Composite Discs-a CAD Technique .................................................. 135

D. G. GORMAN (National Institute for Higher Education, Limerick, Ireland) and J. P. HUISSOON (Trinity College, Dublin, Ireland)

11. Optimization of Laminated Shells with Multiple Loading Conditions and Fabrication Constraints ............................. 144

R. T. BROWN (Atlantic Research Corporation, Alexandria, USA) and J. A. NACHLAS (Virginia Polytechnic Institute and State University, Blacksburg, USA)

Contents Xl

Session V: Research and Development: Marine Applications (Chairman: L. N. PHILLIPS, lOBE:, Royal Aircraft Establishment,

Farnborough, England)

12. Recent Developments in Polyester Matrices and Reinforce­ments for Marine Applications, in Particular Polyester/ Kevlar Composites ............................................................. 158

L. S. NORWOOD (Scott Bader Co. Ltd, Wellingborough, England) and A. MARCHANT (Anthony Marchant and Associates, Rumsey, England)

13. The Testing and Analysis of Novel Top-Hat Stiffener Fabrication Methods for use in GRP Ships ....................... 182

A. K. GREEN and W. H. BOWYER (Fulmer Research Laboratories Ltd, Slough, England)

14. The Development of Improved FRP Laminates for Ship Hull Construction ...................................................................... 202

1. BIRD and R. C. ALLAN (Admiralty Marine Technology Establishment, Dunfermline, Scotland)

Session VI: Research and Development: Modelling Techniques (Chairman: A. W. LEISSA, The Ohio State University, USA)

15. Development of Cylindrically Orthotropic Model Material for Transmission Photoelasticity ........................................ 224

P. K. SINHA (Bihar College of Engineering, Patna, India) and B. L. DHOOPAR (Indian Institute of Technology, Kanpur, India)

16. Photoelastic Techniques for the Complete Determination of Stresses in Composite Structures ........................................ 235

R. PRABHAKARAN (Old Dominion University, Norfolk, USA)

17. A Boundary Layer Approach to the Calculation of Transverse Stresses Along the Free Edges of a Symmetric Laminated Plate of Arbitrary Width Under In-Plane Loading ............ 247

D. ENGRAND (Office National d'Etudes et de Recherches Aerospatiales, Chat ilion , France)

xii Contents

Session VII: Physical and Mechanical Characteristics (1) (Chairman: D. HULL, University of Liverpool, England)

18. On the Orthotropic Elastic Behaviour of a Rubber Composite .......................................................................... 262

A. P. S. SELVADURAI (Carleton University, Ottawa, Canada) and N. MOUTAFIS (University of Aston, Birmingham, England)

19. The Viscoelastic Response of a Graphite/Epoxy Laminate. 285 H. F. BRINSON and D. H. MORRIS (Virginia Polytechnic and State University, Blacksburg, USA), W. I. GRIFFITH (Michelin Corporation, Greenville, USA) and D. DILLARD (University of Missouri, Rolla, USA)

20. Viscoelastic Properties of Composite Materials .................. 301 A. CARDON and CL. HIEL (Vrije Universiteit Brussel, Brussels, Belgium)

Session VIII: Structural Analysis: Platework Systems (Chairman: D. W. WILSON, Center for Composite Materials, University of

Delaware, USA)

21. Advances in Vibration, Buckling and Postbuckling Studies on Composite Plates ............................................................... 312

A. W. LEISS A (The Ohio State University, Columbus, USA)

22. On the Use of the Effective Width Concept for Composite Plates ................................................................................. 335

J. RHODES (University of Strathclyde, Glasgow, Scotland) and I. H. MARSHALL (Paisley College of Technology, Paisley, Scotland)

23. Unsymmetrical Buckling of Laterally Loaded, Thin, Initially Imperfect Orthotropic Plates ............................................. 352

I. H. MARSHALL (Paisley College of Technology, Paisley, Scotland)

Contents xiii

Session IX: Structural Analysis: Structural Systems (Chairman: R. M. JONES, Southern Methodist University, Dallas, USA)

24. The Effect of Mode Interaction in Orthotropic Fibre Reinforced Composite Plain Channel Section Columns ...... 366

A. R. UPADHYA (National Aeronautical Laboratory, Bangalore, India) and J. LOUGHLAN (Cranfield Institute of Technology, Bedford, England)

25. The Stability Analysis of a Continuum/Skeletal Fibre Matrix System ............................................................................... 383

v. G. ISHAKIAN and L. HOLLAWAY (University of Surrey, Guildford, England)

26. The Post buckling Behaviour of Composite Box Sections 402 W. M. BANKS and J. RHODES (University of Strathclyde, Glasgow, Scotland)

Session X: Physical and Mechanical Characteristics (2) (Chairman: L. S. NORWOOD, Scott Bader Co. Ltd, Wel/ingborough,

England)

27. The Effect of Thermal Strains on the Microcracking and Stress Corrosion Behaviour of GRP .................................. 415

F. R. JONES, A. R. WHEATLEY and J. E. BAILEY (University of Surrey, Guildford, England)

28. Electrically Conductive Prepreg Systems ............................ 430 G. L. PATZ (Hexce/ Corporation, Dublin, USA)

Session XI: Structural Evaluation Techniques (Chairman: E. ANDERSON, Battelle Laboratories, Geneva, Switzerland)

29. Analysis of Composite Materials by Dynamic Thermomechanometry (Dynamic Mechanical Analysis) ..... 438

P. BURROUGHS and J. N. LECKENBY (Du Pont (UK) Ltd, Stevenage, England)

xiv Contents

30. Evaluation of Composite Structures by Stress-Wave-Factor and Acoustic Emission ....................................................... 450

A. T. GREEN (Acoustic Emission Technology Corporation, Sacramento, USA)

3l. Vibration Testing of Composite Materials ......................... 463 J. L. WEARING and C. PATTERSON (University of Sheffield, England)

Session XII: Design (Chairman: W. M. BANKS, University of Strathclyde, Scotland)

32. A Minimum Energy Composite Automobile ...................... 475 R. M. McLAY (COMtech Inc., Essex Junction, USA) and J. BUCKLEY, T. FLOYD and D. VIENS (The University of Vermont, Burlington, USA)

33. Structures in Reinforced Composites .................................. 484 W. S. CARSWELL (National Engineering Laboratory, East Kilbride, Scotland)

34. Properties and Performance of GRC ................................. 496 B. A. PROCTOR (Pilkington Brothers Ltd, Ormskirk, England)

Session XIII: Experimental Studies (Chairman: E. J. SMITH, Pilkington Brothers Ltd, Ormskirk, England)

35. Buckling of Plates trips-An Evaluation of Six Carbon-Epoxy Laminates .......................................................................... 512

J. F. M. WIGGENRAAD (National Aerospace Laboratory, Amsterdam, The Netherlands)

36. The Damage Tolerance of High Performance Composites. 536 R. J. LEE (University of Bath, England) and D. C. PHILLIPS (A ERE, Harwell, England)

37. Tensile Fatigue Assessment of Candidate Resins for Use in Fibre Reinforced Composite Repair Schemes ..................... 555

D. P. BASHFORD and A. K. GREEN (Fulmer Research Laboratories Ltd, Slough, England) and K. F. ROGERS and D. M. KINGSTON-LEE (Royal Aircraft Establishment, Farnborough, England)

Contents xv

38. Temperature Increase in SMC Fatigue Testing .................. 573 S. V. HOA and S. LIN (Concordia University, Montreal, Canada)

Session XIV: Fabrication Studies including Natural Fibre Composites (Chairman: C. L. PHILLIPS, Scott Bader Co. Ltd, Wellingborough,

England)

39. A Unique Approach to Fabricating Precision Space Structures Elements ........................................................... 580

H. COHAN and R. R. JOHNSON (Lockheed Missiles & Space Co. Inc., Sunnyvale, USA)

40. Manufacturing Methods for Carbon Fiber/Polyimide Matrix Composites ........................................................................ 592

W. C. MACE (Lockheed Missiles & Space Co. Inc., Sunnyvale, USA)

41. The Use of Natural Organic Fibres in Cement: Some Structural Considerations ................................................... 602

D. G. SWIFT (Kenyatta University College, Nairobi, Kenya)

42. On the Possibility of Using Natural Fibre Composites 618 K. G. SATYANARAYANA,A. G. KULKARNI, K. SUKUMARAN, S. G. K. PILLAI, K. A. CHERIAN and P. K. ROHATGI (Regional Research Laboratory (CSIR), Trivandrum, India)

Session XV: Fracture and Failure Analysis (Chairman: J. ANDERSON, Paisley College of Technology, Scotland)

43. Stress Intensity Factor Measurements in Composite Sandwich Structures ........................................................... 633

I. ROMAN, H. HAREL and G. MAROM (The Hebrew University of Jerusalem, Israel)

44. Progressive Failure Model for Advanced Composite Laminates Containing a Circular Hole ............................... 646

D. Y. KONISHI (Rockwell International, Los Angeles, USA), K. H. Lo (Shell Development Company, Houston, USA) and E. M. Wu (Lawrence Livermore Laboratories, Livermore, USA)

xvi Contents

Session XVI: Research and Development: Analysis of Laminated Structures (Chairman: J. RHODES, University of Strathclyde, Scotland)

45. Nonlinear Response of Angle-Ply Laminated Plates to Random Loads .................................................................. 656

C. MEl (Old Dominion University, Norfolk, USA) and K. R. WENTZ (A FWALj FIBED Flight Dynamics Laboratory, Ohio, USA)

Session XVII: Physical and Mechanical Characteristics (3) (Chairman: A. R. BUNSELL, Ecole des Mines de Paris, France)

46. Effects of Elastomeric Additives on the Mechanical Properties of Epoxy Resin and Composite Systems ............ ................ 674

R. J. MOULTON (Hexcel Corporation, Dublin, USA) and R. Y. TING (Naval Research Laboratory, Orlando, USA)

Session XVIII: Finite Element Studies (Chairman: C. PATTERSON, University of Sheffield, England)

47. A Comparison of the Failure Pressure as Predicted by Finite Element Stress Analysis with the Results of Full Scale Burst Tests on GRP Flanges ....................................................... 690

A. MUSCAT! and R. BRADFORD (CEGB, Bristol, England)

48. Elastic-Plastic Flexural Analysis of Laminated Composite Plates by the Finite Element Method ................................. 704

F. F. MAHMOUD (Zagazig University, Egypt)

Index .......................................................................................... 713