A Modified Boundary Element Method for the Scattering Field of Lamb Wave Interactions with a Thinning Defect

摘要

In this paper, a modified boundary element method (BEM) is proposed to solve the two-dimensional scattering fields of lamb waves in plates with a defect. For an infinite long plate, the infinite boundary integral in the traditional BEM is directly replaced by finite integral. Therefore, Spurious reflected waves are generated due to the truncated boundaries, which will cause calculation errors. In order to avoid these errors, the omitted integral terms in the traditional BEM are calculated by the reciprocity theorem in elastodynamics and the results are substituted into the traditional BEM. Meanwhile, this modified method is applicable to solving scattered fields for both single-layer and multi-layer models. At the end of this paper, the calculated results for single-layer and multi-layer plates with typical defects are shown, and the convergence of scattering coefficients is verified. Furthermore, the modified BEM, as an efficient numerical calculation method, can be used to study the forward problems of defect detection.