Three dimensional modified BEM analysis of forward scattering problems in elastic solids

In this paper, a three-dimensional modified boundary element method (BEM) is proposed to solve the guided wave scattering problem by cavity-type flaws in an infinite plate. The aim of modification is to correct the artificial scattering introduced by inevitable modal truncation at far-field in the traditional BEM model. The far-field wave displacement fields beyond the BEM model are assumed to be the summation of orthogonal propagating guided wave patterns, and are finally incorporated into BEM equation sets as the modified items to account for the contribution of infinite boundaries traditionally omitted. With this improvement, the spurious reflected waves are eliminated. The method is formulated for a three-dimensional homogeneous, isotropic, elastic plate and its implementation is discussed in details. The formulation is finally validated for several benchmark problems.