Slightly inhomogeneous surface wave in an isotropic half-space in the presence of weak anisotropy by its surface

Abstract

The solution of the problem concerning the transformation of a volume SH wave propagating along an isotropic elastic half-space with a free surface into a new wave by laying on the half-space boundary a weakly anisotropic layer with cubic symmetry is presented. Two types of the weakly anisotropic layers are considered: the layer in which the shear wave velocity is the same as the half-space (‘‘neutral’’ layer) and the layer in which the velocity of the shear wave is smaller than the velocity of the shear wave in the half-space (‘‘decelerating’’ layer). The elastic moduli of a layer’s material are slightly distinguished from corresponding elastic moduli of the isotropic half-space. It is shown that the new wave is the slightly inhomogeneous quasitransverse surface wave of SH type, because among three displacement components on this wave, the transverse one, which is parallel to the interface of two mediums, predominates. Wave velocities are slightly distinguished from the velocity of the volume SH wave, but their depths of penetration into the half-space are considerably more than a depth of the Rayleigh wave localization. As an example, a two-layered medium is considered, where materials for the layer and half-space used are anisotropic and isotropic tungsten, respectively.