The Scattering Of SH-Wave By Subsurface Circular Cavities In A Elastic Half-space With A Layer Above

The question about scattering of SH-wave by circular cavities in a elastic half-space is one of problem concerned by elastic dynamics, the subject selected has academic significance and engineering background.The investigation about scattering of SH-wave by circular cavities in a elastic half-space with a layer above is given, based on complex function method,wave function expansion method and circular arc supposition method .A circuler arc of large radius is used first to approximate straight boundary of layer so as to turn straight boundary question into crooked boundary question. By using the theory of Helmholtz then, the general solution of wave function is given and infinite linear algebraic equations with unknown factors of wave function can be found by Fourier-Hankel series expansion technology and boundary conditions, so we can gain result by intercepting the equations. The dynamic stress concentration factors around the circular cavity are discussed in numerical examples. The result show that existence of a layer above a half-space, even if it is very thin, has great effect on scattering of SH-wave, and variation of stiffness and thickness of the layer can remarkably change the dynamic stress concentration of circular cavity. When tactic direction of two cavities is in the same direction of incident wave's, the scattering of SH-wave is shielded and dynamic stress concentration is weakened than single cavity's; When tactic direction of two cavities is not in the same direction of incident wave's, There is a amplification to scattering of SH-wave.