Scattering of SH waves by embedded cavities

Abstract Scattering of plane SH waves by sub-surface circular cavities and thin slits in a semi-infinite elastic medium is analyzed in this paper. Two methods of solution are used to obtain the displacements on the free-surface. One of these is a method of matched asymptotic expansion that is very effective when the wavelength is long compared to the dimensions of the cavity (or the crack). The other is a combined finite element and analytical technique, which is useful in the long to intermediate wavelength range. The results obtained by these two techniques are shown to agree quite well for long wave-lengths. Numerical results for the surface displacements for various incident wave angles are seen to depend significantly on the depth and size of the cavity and the crack. In the latter case the orientation of the crack has a significant influence on the scattered field.

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