A three-dimensional indirect boundary integral equation method for modeling elastic wave scattering in a layered half-space

摘要

A new indirect boundary integral equation method (IBIEM) is proposed in this study to solve three-dimensional (3-D) elastic wave scattering by heterogeneities in a multi-layered half-space, employing Green's function of distributed loads on equivalent circular elements, thus avoiding the element discretization on layer interfaces. The proposed method enables the fictitious loads to be directly distributed on the surfaces of scatterer and the weak singularity to be tackled by analytical integration. Also, the radiation condition in the semi-infinite layered medium can be satisfied accurately, and the memory requirements can also be greatly reduced, especially for a large number of layers or gradient medium. The numerical accuracy was verified through comparisons with existing results and the numerical convergence was also confirmed. The results clearly demonstrate the simplicity and effectiveness of the method, and also reveals the complicated scattering characteristics in a layered half-space that are dominated by the resonant properties of the layered medium. (C) 2019 Published by Elsevier Ltd.