A semi-numerical method for elastic wave scattering calculations

This paper is concerned with the calculation of elastic wavefields in stron gly heterogeneous media containing scatterers of arbitrary shape and size. A hybrid method is described in which the elastodynamic field within a fini te region enclosing the scatterers is modelled by finite elements while the field away from this region is represented by means of a suitable set of w ave functions. Application of a variational principle and the continuity co nditions at the interface between the two regions lead to a system of linea r equations that is solved by standard techniques. The hybrid method extend s the applicability of the finite element method to wave propagation proble ms in unbounded media by rigorously modelling the radiation field. The meth od is used to calculate the elastodynamic field in a plate of finite thickn ess and infinite lateral dimensions containing geometric discontinuities.