Dynamic Green’s Function of Finite Media by Finite Difference Method

A three-dimensional finite difference method (FDM) has been developed for the computation of elastic wave propagation in finite media containing a macrocrack, with a new treatment of boundary conditions of surfaces. The method can be used for the simulation of dynamic Green’s functions of an arbitrary rectangular parallelepiped medium with a macrocrack such as a compact tension (CT) specimen. The validity of the method has been confirmed by comparison with theoretical solutions of the plate problem for a monopole source and a double source. The method was then applied to the computation of Green’s functions for a seismic moment in CT specimen. Evaluation of Green’s function by this three-dimensional FDM leads to more accurate acoustic emission (AE) source characterization.