RADIATION AND FOCUSING OF SH0 ELASTIC-WAVES IN ANISOTROPIC SHEETS

The excitation and propagation of SH0 elastic waves in anisotropic sheets are studied. The wave equations are solved by the method of Fourier transforms. It is shown that the velocities determined -in the far-field region are the group velocities in the directions of measurement. Analytical and numerical simulation results are presented. These results are in good agreement with our own measurements made on an anisotropic aluminum sheet, and they correctly explain the experimental data of other investigators, a satisfactory interpretation of which has been wanting. Our analysis shows that the energy of radiated SH0 waves in anisotropic sheets tends to focus in some directions, which can be shown to be the directions of maximum phase velocities for weakly orthotropic sheets. Quantitative comparison is made between this theoretical prediction and our experimental measurements.