Wave Propagation in Layered Anisotropic Media with Applications to Composites

Abstract

This chapter describes the task of developing models for constructing the effective composite elastic properties of straight as well as undulated fibers. Typically, structural fibrous composites are composed of brittle, stiff fibers embedded in a matrix of a more ductile material, which bonds the fibers together and acts as a load-transfer medium. In principle, an infinite medium constructed from such combinations is referred to as the “bulk composite medium.” Out of this large medium, a thin layer is isolated, bounded by two planes that are parallel to the fiber direction. This layer is called lamina. Across its thickness, a lamina can have one or more fibers. Even if the fiber and matrix constituents of the lamina are assumed to be isotropic, the lamina will be anisotropic and the fiber direction constitutes a principal material direction. For the construction of desired effective material properties, the geometry commonly employed belongs to an infinite elastic medium reinforced with circular cross-sectional fibers of different material.