Elastodynamic guided wave scattering in infinite plates

The scattering of elastic guided waves by defects in two-dimensional in nite plates is analysed in the plane and antiplane cases, corresponding, respectively, to Lamb and SH modes. A hybrid boundary element– nite element technique is used, where the defect neighbourhood is discretized with quadratic boundary elements and the radiation condition in the plate is satis ed through a normal mode expansion. A semi-analytical nite-element technique is applied in the in nite plate to calculate its dispersion curves and normal modes. This hybrid technique, which showed excellent performance in the solution of Lamb wave re ection at the edge of semi-in nite plates, is extended in this paper to a wider range of problems, such as Lamb mode scattering by delaminations and surface defects and SH mode interaction with step discontinuities.