Rays and trasport equation for pre-stressed solids

Wave propagation in elastic solids is investigated via the ray approach. The solid is taken to be heterogeneous and subject to an initial stress thus allowing the occurence of a body force. In this context, quite unusual in the literature, the general relations are found for the terms of the asymptotic expansion. Then the eikonal and the transport equations are detrmined for both transverse and longitudinal waves. The effect of the initial stress is examined in both the isotropic and the anisotropic case