Numerical simulation and visualization of elastic waves using mass-spring lattice model

A computer program package has been developed for simulation and visualizat ion of two-dimensional elastic wave propagation and scattering using the ma ss-spring lattice model (MSLM) and, for comparison, a finite difference mod el. To assess the reliability of the numerical schemes, their convergence a nd accuracy have been analyzed using the Taylor series expansion and the vo n Neumann analysis methods. As a result, the grid spacing-time increment co mbinations previously adopted in the literature have proved to be non-optim al. The optimal combinations have been found and shown to yield the most ac curate results with the least computation time, particularly in the high fr equency regime. Using these algorithms, a program package has been developed in Visual C++( R) (Microsoft, Redmond, WA) with graphic user interfaces for convenient exp loration of visualized results. Numerical results have been obtained for so me fundamental problems in ultrasonic testing such as plane waves incident on cracks. All numerical results have shown excellent qualitative agreement s with the analytical results of the wave physics, as the reflected, diffra cted, head, and Rayleigh waves have been observed. Also, for numerical resu lts with anisotropic media, the cusps on the shear wavefronts have been obs erved. Finally slight modification of the modeling method for free surfaces has led to more accurate prediction of Rayleigh waves.