ABSTRACT
Composites are the heterogeneous materials that exhibit anisotropic character, which means that the deformations or motions in all coordinate directions will be coupled. That is, an axial impact will create a bending motion and or a torsional motion depending on the level and nature of anisotropy. From the wave propagation point of view, the coupled motion will make the wave propagation very complex introducing multiple cut-off frequencies and different propagation characteristics. In this chapter, a very brief introduction to the composite materials, laminated composites, and the evaluation of their material properties and their homogenization is presented. The knowledge and understanding of the basic theory of composites is fundamental to the understanding of wave propagation in the material presented in the later chapters. This chapter outlines the theory only very briefly and the reader is advised to refer to many advanced textbooks in this subject such as [171, 351].
