Design and manufacture of composite structures

Design and manufacture of composite structures

Book reviews Design and Manufacture of Composite Structures G. Eckold Woodhead Publishing Ltd, Cambridge, A few years ago, it was difficult to...

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Book reviews

Design

and Manufacture

of Composite

Structures

G. Eckold Woodhead

Publishing

Ltd, Cambridge,

A few years ago, it was difficult to identify, let alone recommend, a text on the design of composite structures. Most books on ‘design’ actually covered ‘analysis’ (including laminate behaviour and fracture mechanics) in some detail, and the engineering application of rather complex mathematical solutions was largely ignored. Recently, several publishers, including Woodhead, have gone some way to filling this important gap. Eckold’s book is a welcome addition to the current range of titles, and clearly makes the connection between mathematical analysis and engineering. The scope of the book is sufficient to emphasize the crucial interactions between materials, design and manufacture, an understanding of which is so important for the successful application of composites. Having said that, there are some sections where the choice of topics and the space devoted to them is a little unbalanced. A fairly short chapter describes materials and their properties - this is reasonably comprehensive, although one would have wished for some discussion of core materials at this point. Chapter 3 deals with the mechanics of composite materials, including the basics of laminate analysis and failure criteria. Here,

Rheology Aleksandr

Eckold chooses to devote some 12 pages to micromechanics. He lists an admirably complete selection of mixture theories for mechanical and physical properties, yet omits to give the reader any guidelines regarding applicability or reliability. It is at this point in the book that its greatest weakness is evident - that of persistent typographical errors. I counted 11 in Chapter 3 alone. Some merely amusing (short bean shear), but most occur in mathematical expressions (e.g. missing brackets, incorrect subscripts, undefined terms), and could result in genuine confusion for an innocent reader. Errors occur throughout the book, and detract from the clarity of Eckold’s writing. The principal structural elements (beams, plates and shells) are dealt with in an uncompromisingly mathematical fourth chapter which contains no less than 145 equations. The author has himself carried out useful work in cylindrical composite structures, and a good summary is to be found here. However, most engineers well need to read this in conjunction with a more friendly design guide, paying particular attention to the limits of applicability of the various approaches.

A diverse selection of design aspects are gathered together in Chapter 5, including joining, impact and fatigue. Again, the content is good but unbalanced - sandwich structures are given barely two pages, while residual stress gets nine. Although ‘manufacture’ appears in the title, only about 30 pages are given to a description of the main processing routes in Chapter 6. Costs and economics are not tackled in any manufacture/design issues. The book concludes with a good discussion of composite applications in such areas as aircraft, process plant, medical and offshore. Many examples are not particularly recent, and several are the product of Eckold’s group at AEA Technology, Harwell. This enables him to go into more detail than is usual in text books. In a sense, this chapter is the most valuable in the book, giving the reader a flavour of the detailed design work necessary for original applications of a still under-exploited material. Stephen Grove Advanced Composites Manufacturing Centre University of Plymouth, UK

Fundamentals Yakovlevich

Chemtec Publishing,

Malkin 1994, hardback, 324 pages, US $135

The front cover suggests that this is one in a series of titles on ‘Fundamental Topics in Rheology’; however, no other information is given about other books intended for such a series. Rheology, and so too the fundamentals of rheology, are of considerable importance in the field of composites manufacturing. However, this is not a volume written with the composites applications in mind. In a one-page section on page 196 on linear anisotropic materials, it is recorded that reinforced plastics are an important representative of that family, but that is about all. The book is primarily directed towards those with a broad interest in rheology and, in

72

UK 1994, 397 + viii pp., ISBN 1 85573 0510

COMPOSITES

particular, towards those primarily interested in theoretical aspects of that subject. The book has three introductory chapters dealing with the basic concepts of rheology, stresses and deformations. There follows a seemingly inappropriately named chapter on ‘Rheological equations of state’, which actually gives a rather general description of unusual rheological phenomena. Chapters 5, 6 and 7 respectively deal with ‘Rheological viscous liquids’, ‘Elastic solids’ and ‘Viscoelasticity’. Before the short ‘Subject index’, there is a rather intimidating section on ‘Nomenclature’, identifying about 200 symbols used in the text -

PART A Volume 27A Number 1 1996

some, such as the Greek lambda, with no less than five distinct meanings. The main value of the work is in its appreciation of historical perspective. The reference sections abound with citations of truly classical texts from the 17th to the early part of the 20th century. For example, chapter 5 entitled ‘Rheological viscous liquids’ is illustrated with 13 references of which nine are before 1940 and only one (to the work of Professor Malkin and a colleague) after 1975. Strangely, the equally long Chapter 5 on ‘Elastic solids’ contains no references - one might speculate how the somewhat acerbic Robert Hooke might have felt about that. Some people may