Development of three-dimensional ultrasonic simulation and its application

A computer simulation technique for 3-dimensional ultrasonic waves was developed for visualization and investigation of ultrasonic propagation in isotropic and anisotropic solids with defects. The technique is similar to a finite-difference method (FDM) and a mass-particle model method, but uses a new nodal calculation method based on fundamental consideration of an elastic wave equation. The new method simplifies calculations on boundary nodes, so that it requires no pseudonodes as in the FDM, and is applicable to not only anisotropic but also complex materials including defects. A program has been developed for 3-dimensional calculation, but it requires the huge memory and high speed of supercomputers. Due to the limitation in computer performance, we present here conventional applications under the 2-dimensional condition including 3-dimensional motion. Some simple applications are shown for ultrasonic propagation in anisotropic (hexagonal) materials and layered materials, and wave scattering at a crack.