Mechanics of Composite Structures

Abstract

5R4. Mechanics of Composite Structures. - LP Kollar and GS Springer. Cambridge UP, Cambridge, UK. 2003. 480 pp. ISBN 0-521-80165-6. $95.00.Reviewed by M-A Erki (Dept of Civil Eng, Royal Military Col of Canada, PO Box 17000 Station Forces, Kingston ON, K7K 7B4, Canada).This comprehensive book presents traditional topics of structural mechanics that target the topics of interest for designers of aerospace, land, and marine structures, namely plates, beams, and shells, including where appropriate the analyses for their buckling, vibrations, deformations, and displacements. While the topics are familiar to designers using isotropic materials, in this book they are presented for anisotropic composite materials of all types, which are long-fiber composites, short-fiber composites, particulate composites, unidirectional lamina, biaxial weave woven fabric, and triaxial weave woven fabric. Chapter 1 illustrates these materials. It describes the structure of laminate composites and how the individual plies contribute to the laminate behavior. The chapter also defines the various levels of analysis for a structure made of a laminated composite, from the micro (analysis of the matrix and fiber) to macro (analysis of the composite), ending with structural analysis of components, herein plates, beams, and shells. The foundation for all subsequent derivations and analyses in the book are given in Chapter 2. It presents the generalized 3D relationships between displacements and strains and between strains and stresses, via equilibrium equations. The stress-strain relationship is developed first for general anisotropic material, followed by the simplifications that can be made for monoclinic material, orthotropic material, transversely isotropic material, and isotropic material. The differences in analytical approaches for plane strain and plane stress analyses are carefully explained using the specific examples for all these materials for the conditions of free end and built-in ends. The effect of temperature and moisture content on strains and stresses is discussed for both the plane strain and plane stress conditions.A section on boundary conditions and how these are applied to obtain solutions to the equilibrium, stress-strain, and strain displacement equations is given. Continuity conditions between laminated layers that are assumed perfectly bonded are described. Stress and strain transformations using direction cosines and transformation of the stiffness and compliance matrices are discussed for the plane-strain and plane-stress conditions. Finally the strain energy equations are derived, and the Ritz Method is summarized as a solution method for these. The chapter ends with a comprehensive summary of the chapter contents and a numerical example. Chapter 3 discusses the analysis of laminated composites and the contribution of the behavior of individual plies to the overall behavior of the laminate. Stiffness matrices for thin laminates, an example of symmetrical laminate, balanced laminate and orthotropic laminate, isotropic laminate, and quasi-isotropic laminate are illustrated with numerical examples. The next five chapters present the analyses for the basic structural members composed of composite materials, namely thin plates, sandwich plates, solid and thin-walled beams without and with shear deformations, and shells, all with numerical examples as appropriate. Unique considerations for the finite element analysis of composite materials and composite material structures are described in Chapter 9. Chapter 10 discusses failure criteria for the basic types of composite materials, and Chapter 11 summarizes composite material micromechanics. Three valuable appendices give supplementary material of value to the designer. They are the cross-sectional properties of thin-walled composite beams; the buckling loads and natural frequencies of orthotropic beams with shear deformations; and typical composite material properties. Owing to the clarity and breadth of its content, Mechanics of Composite Structures makes a valuable contribution to the field of analysis and design using composite materials. It is well illustrated throughout. Of note, the examples given throughout are truly excellent, because they are both relevant to the development of the concepts presented and practical for designers. The authors have made a special effort to make the book self-contained so that it can be equally suitable as a text for self-study, senior undergraduate, or for a graduate course.