ACOUSTIC-WAVES GENERATED BY A TRANSIENT LINE SOURCE IN AN ANISOTROPICHALF-SPACE

The Lamb's problem for an elastic anisotropic and homogeneous half spa ce is solved for a line source. The calculation of the Green's functio ns, based on the Cagniard-de Hoop method, is performed, for the cubic system of symmetry. The free surface is a symmetry plane. In addition, the line source may be either parallel to an axis of symmetry, or alo ng any other direction. As an illustration, the waveforms of the norma l displacement field are then calculated at different locations and fo r two different line sources. This theoretical study models the genera tion of acoustic waves with a laser beam focused down by a cylindrical lens. The inspection of Cagniard-de Hoop's contours and singular poin ts in the complex plane describes most of the physical phenomena. For instance, the propagation of both Rayleigh and pseudo-surface waves, a nd the presence of caustics are clarified.