ABSTRACT

We have already described in some detail two examples of guided acoustic waves, namely Rayleigh waves on a surface and Lamb waves in a plate. Both of these problems were solved using the potential method, which can in fact be used to solve any acoustics problem in isotropic media. However, the potential method cannot be extended to anisotropic media. This is a definite shortcoming for quantitative treatment of acoustic waveguides, because while the isotropic model is simple and useful to describe the global behavior, most acoustic waveguides are in fact made from anisotropic materials. Thus it would be useful to have a formalism that works in this case, and that is provided by partial wave analysis, which will be used in this chapter.