Ultrasonic echo responses from targets in solid media using finite difference methods

Pulse-echo scattering in an isotropic elastic solid is investigated using finite difference methods. The aim of the study is to investigate the forward scattering problem using realistic defects and realistic (i.e. nonplanar) incident waves. New finite difference nodal formulations for the cylindrically symmetric problem are presented. It is shown how properly to incorporate a specified input pulse shape. The evolution of the incident and scattered waves is presented pictorially. A comparison of calculated pulse-echo signals with real data shows excellent agreement. It is argued that the methods will be valuable in testing models, and in improving target characterisation from real data.