The spreading of nonlinear elastic surface waves

Abstract

Al~traet.A theory for the lateral spreading of a beam of nonlinear surface acoustic waves across the surface of an arbitrary, homogeneous, elastic half-space is developed. The resulting evolution equation generalizes that obtained for tmi-directional waves by replacing an ordinary derivative by a diffusion operator of Schr6dinger type. The coefficients arising in the evolution equation are related to partial derivatives of the dispersion relation for linearized surface waves on the half space. Details are given for isotropic materials and for two special cases of beams travelling along axes of high elastic symmetry.

Extraction of depth profiles of third-order elastic constants in cracked media

“…If effects of attenuation and diffraction are taken into account [13,14,15,16,17], both complex amplitudes A 1 and A 2 would depend on X and even on a stretched lateral coordinate. We shall not consider such effects here, but focus on the interaction coefficient β R , the acoustic nonlinearity parameter (ANP) for Rayleigh waves.…”