New developments in the finite difference modelling of pulse-echo scattering

Pulse-echo scattering in an elastic solid has previously been modeled by the authors using finite difference methods for cases where the problem has full cylindrical symmetry. The method helps to track the many different types of waves and their scatterings. Some new results and approaches are reviewed. It is shown how the finite difference method can be modified to track the components satisfying the shear and compression wave equations separately. An extension to certain types of nonsymmetrical defect is indicated. New and improved free surface nodal formulations are discussed