Fibrous composites in structural design

Fibrous composites in structural design

358 preach is that the resulting equation one has to solve is simpler than that governing the general situation. Indeed, it is frequently an ordinary...

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preach is that the resulting equation one has to solve is simpler than that governing the general situation. Indeed, it is frequently an ordinary, instead of a partial, differential equation. This book is concerned with the general theory of such solutions and highlights their interpretation as “intermediate asymptotics” - that is, as solutions which are valid in the region outside the immediate vicinity of the disturbance - e.g. away from the leading edge of the plate in the classical boundary layer solution; away from the immediate vicinity of the tip of the crack in fracture mechanics solutions; or away from the point of explosion in the blast wave analysis. The author, who is one of the world’s leading applied mathematicians, has written a novel and stimulating book. It is aimed, however, principally at other applied mathematicians. I.F. COLLINS

Fibrous Composites in Structural Design (Proceedings of the Fourth Conference, San Diego, U.S.A., November, 1978), by Edward M. Lonoe, Donald W. Oplinger and John J. Burke (Eds.), Plenum, New York, 1980. ISBN o-306-40354-4, xviii + 873 pages, 210 X 272 mm, numerous illustrations, hardcover US$85.00 (plus 20% outwith the U.S.A.). Most readers of the Journal of Mechanical Working Technology possess, in varying degrees, some appreciation of the splendid heritage conjured up by the words “composite technology” which, since the time Egyptians first put straw into bricks and in the last two decades particularly, has become a respectable subject for serious study. Fibre technology itself is not new - it dates back to the early days of reinforced concrete and goes into the areas where conventional materials can no longer withstand or deliver what is asked of them. It is with the development of analytical predictions, however, that a greater fundamental understanding of composite phenomena is being realised than ever before. The road to success in composite technology is perhaps littered with costly failures: what went totally wrong so often even in the early 70s was that an existing design or component manufactured in conventional material was used for making the same component in a composite. A composite design must be a new design using the material to its best advantage and the correct lay-out techniques should be employed for each application. The four facets to the designing of medium-to-large structures in composites may be well summarized as: (i) macro-design - designing the overall shape to give maximum stiffness with the minimum material; (ii) micro-design - orientating the fibres in the composite to give maximum effect; (iii) optimisation of the maximum strain limitation of the composite; and (iv) determination of the creep and fatigue properties of the composite under constant and intermittent, static and dynamic, loads. Composite materials are still under development and, at this stage, new

359 books on broad aspects of the subject are to be unreservedly welcomed. It is a formidable task, however, to bring together recent development in composite materials, especially isolated topics, with their use in safety-related structures. It is also all t o o easy for a b o o k which summarises papers delivered at a conference to lack coherence. Happily this is avoided with the present volume because of the careful way in which the Editors have selected their authors and thereby the topics. The b o o k is a composite volume of some fifty papers and covers comprehensive, rational and multi-disciplinary approaches to the problem of the design and production of fibrous composite structures. The texts are aimed at structural designers, materials and aerospace scientists, polymer chemists/physicists, and mechanical engineers specialized in industrial fabrication techniques. The b o o k may also be eminently readable by a wide range of people, moderate-to-highly specialized in other fields of engineering b u t with peripheral interest in composite technology. Papers are grouped together under session headings entitled: Aircraft Structures; Missile and Space Applications; Crashworthiness, Impact Damage, Post-Buckling and Dynamic Response; Special Design Considerations (composite repair, cost estimating, etc.); Laminate Plate Theories, Edge Effects, Flaw Growth; Helicopter Applications; Composite Joints; Other Applications (hydrofoil structures, flywheels, automative parts, etc.); Reliability and Durability Analysis; and Environmental Effects. After a brief statement of the problem, most of the papers make a useful excursion, with generous illustrations, through the various stages of design criteria, development of tooling, experimental techniques and the resulting conclusions and/or proposals. The variables in a design, matching these characteristics by the right material, using composite properties {related to failure processes, reliability, durability, environmental degradation and foreign object damage vulnerability) to their full advantage in the designing of structures, are all well presented. The contributors are drawn mainly from the research and development centres of the American aircraft industry and some large public institutions; in fact, only about a couple of the American Universities are represented in this book. From an "industrial" viewpoint some of the papers reflect both the growing influence of high-modulus, light-weight and high-strength fibre-reinforced materials on structures technology and the impact of these new materials on structural hardware, which will continue to require careful investigation in the coming years. The Fourth Conference on "Fibrous Composites in Structural Design" was a successor to the First-to-Third Conferences on "Fibrous Composites in Flight Vehicle Design". Whilst the first three conferences were aimed at focussing attention on flight vehicle applications of advanced composites which afforded, among other advantages, considerable weight saving, the fourth in the series was the first to give attention to "non-aerospace" applications of fibre-reinforced materials. According to the Editors of this volume, "while the design technolqgy for aerospace applications has reached a state of relative maturity, other areas of application such as military bridging, flywheel

360 energy storage systems, ship and surface vessel components, and ground vehicle parts are in an early stage of development, and it was an important objective to pinpoint where careful attention to structural design was needed in such applications to achieve m a x i m u m structural performance pay-off there is no real reason behind developing a new material or c o m p o n e n t if, by the time it is developed, the market is no longer there. Apart from the categories of professional people mentioned above, who will obtain quickly an almost authoritative grasp of the subject of fabrication and design of non-aerospace hardware with fibrous composites, the reviewer wishes to recommend this book also to managers working in all phases of the materials fabrication industry, who wish to see what is going on with such composites and where they are going; its perusal may stimulate both t h o u g h t and action. The quality of production is in accordance with the high standard to which one is accustomed from Plenum Press. This inevitably expensive book is worth its price and is one of those of which one can say w i t h o u t hyperbole that it should be in every scientific library, both in universities and in industry: since a researcher of the subject will, in all probability, wish to follow the references given (those lengthy American reports many of us long for!) this is perhaps a good location. It seems almost churlish to fault such a polished product, but one minor criticism can be made of the bewildering variety of units which are used, changing even within individual papers; it could have given greater uniformity if either a consistent system of units had been maintained or if, say, SI equivalents could have been given in parenthesis t h r o u g h o u t to aid in making comparisons at this "transitional" stage. Finally, after writing this passage, the reviewer asks himself if he has done justice to such a m o n u m e n t a l work of some 870 pages. He is, however, fortunate indeed that in return for this passage he receives a complimentary copy which he may pick up on m a n y future occasions both to wonder at the marvels of composite technology circa 1980 and to speculate, nervously, on the future t h a t awaits us. S.K. GHOSH

Modern X-ray Analysis on Single Crystals, by Peter Luger, de Gruyter, Berlin, 1980. ISBN 3-110-068303-7, xiii + 312 pages, 170 X 240 mm, numerous illustrations, hard cover DM96.00. Many excellent textbooks have been written on the basic ideas behind X-ray crystallographic techniques and on the application of these techniques to particular problems in, for example, chemistry, metallurgy and materials science. But there has been a need for a step-by-step guide for graduate researchers on how to set about the complete determination of a crystal struc-