Acoustical birefringence of ultrasonic waves in deformed isotropic elastic materials

Abstract

The basic relations of the acoustoelasticity are deduced by means of the infinitesimal wave propagation in a deformed isotropic elastic material. The propagation equation is characterised by the acoustical tensor. This results in the three polarization directions, which are perpendicular to each other and, in general, do not coincide with the principal axes of the stress. When the propagation direction coincides with one of the principal axes of the stress, the former are identical to the latter and the so-called stress-acoustical law holds, which denotes that the magnitude of the acoustical birefringence is proportional to the difference of the secondary principal stresses.