Nonlinear reflection of BAW's at an interface of anisotropic solids

A theory as the basis for solving nonlinear boundary value problems is described in this article. Based upon a careful discussion on nonlinear propagation characteristics of bulk acoustic waves (BAWs) in anisotropic solids, we present an original analysis for the nonlinear reflection of a pure-mode plane wave at an interface of two anisotropic solids, which reveals that the interface may generate freely-propagating second-harmonic waves, and that the reflective and the refractive second-harmonic waves increase two-dimensionally in the bulk. This technique can also be applied to wave reflection problems at other kinds of planar boundaries