Composite Materials

In the past ?ve decades considerable attention has been devoted to comp- ite materials. A number of expressions have been suggested by which mac- scopic properties can be predicted when the properties, geometry, and volume concentrations of the constituent components are known. Many expressions are purely empirical or semi-theoretical. Others, however, are theoretically well founded such as the exact results from the following classical boundary studies: Bounds for the elastic moduli of composites made of perfectly coherent homogeneous, isotropic linear elastic phases have been developed by Paul [1] and Hansen [2] for unrestricted phase geometry and by Hashin and Shtrikman [3] for phase geometries, which cause macroscopic homogeneity and isotropy. The composites dealt with in this book are of the latter type. For two speci?c situations (later referred to), Hashin [4] and Hill [5] derived exact - lutionsforthebulkmodulusofsuchmaterials.Hashinconsideredtheso-called Composite Spheres Assemblage (CSA) consisting of tightly packed congruent composite elements made of spherical particles embedded in concentric - trix shells. Hill considered materials in which both phases have identical shear moduli. In the ?eld of predicting the elastic moduli of homogeneous isotropic c- posite materials in general the exact Hashin and Hill solutions are of th- retical interest mainly. Only a few real composites have the geometry de?ned by Hashin or the sti?ness distribution assumed by Hill. The enormous sign- icance, however, of the Hashin/Hill solutions is that they represent bounds which must not be violated by sti?ness predicted by any new theory claiming to consider geometries in general.

Presents the mechanical and physical behavior of composites Thorough analysis of various composite properties versus composite geometry Gives a better understanding of the behavior of natural composites, the improvement of such materials and the design of new materials with prescribed properties Serves theory and practice

Klappentext

This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. This monograph provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the influence of geometry to materials properties. Composite Materials enables the reader to a better understanding of the behavior of natural composites, improvement of such materials, and design of new materials with prescribed properties.

A number of examples are considered in the book: Special composite properties considered are stiffness, shrinkage, hygro-thermal behavior, viscoelastic behavior, and internal stress states. Other physical properties considered are thermal and electrical conductivities, diffusion coefficients, dielectric constants and magnetic permeability. Special attention is given to the effect of pore shape on the mechanical and physical behavior of porous materials.

Inhalt
Classification of Composites.- Preliminaries on Stress/Strain.- Composite Stress and Geometry.- Composite Stiffness and Geometry.- Composite Eigenstrain/Stress.- Quantification of Geometry.- Composite Theory Elasticity.- Composite Theory Conductivity.- Simplified Composite Theory Elasticity.- Simplified Composite Theory Conductivity.- Diagnostic Aspects of Theory.- Aspects of Materials Design.- Viscoelasticity.- Viscoelastic Composites.- Final Remarks.