|Title:||SH-wave diffraction by a semi-circular hill revisited: A null-field boundary integral equation method using degenerate kernels||Authors:||Jeng-Tzong Chen
|Keywords:||SH-wave;Diffraction;Semi-circular hill;Null-field BIEM;Degenerate kernel||Issue Date:||May-2011||Publisher:||ScienceDirect||Journal Volume:||31||Journal Issue:||5-6||Start page/Pages:||729-736||Source:||Soil Dynamics and Earthquake Engineering||Abstract:||
Following the success of seismic analysis of a canyon , the problem of SH-wave diffraction by a semi-circular hill is revisited using the null-field boundary integral equation method (BIEM). To fully utilize the analytical property in the null-field boundary integral equation approach in conjunction with degenerate kernels for solving the semi-circular hill scattering problem, the problem is decomposed into two regions to produce circular boundaries using the technique of taking free body. One is the half-plane problem containing a semi-circular boundary. This semi-infinite problem is imbedded in an infinite plane with an artificial full circular boundary such that degenerate kernel can be fully applied. The other is an interior problem bounded by a circular boundary. The degenerate kernel in the polar coordinates for two subdomains is utilized for the closed-form fundamental solution. The semi-analytical formulation along with matching boundary conditions yields six constraint equations. Instead of finding admissible wave expansion bases, our null-field BIEM approach in conjunction with degenerate kernels have five features over the conventional BIEM/BEM: (1) free from calculating principal values, (2) exponential convergence, (3) elimination of boundary-layer effect, (4) meshless and (5) well-posed system. All the numerical results are comparing well with the available results in the literature. It is interesting to find that a focusing phenomenon is also observed in this study.
|Appears in Collections:||河海工程學系|
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