Determination of the transient response of an anisotropic layer to an impulsive line-source by the generalized-ray method

In laser-ultrasonic NDE of crystals or composite materials, many devices involve very short pulses (a few nanoseconds), line-like sources and point receivers. In those cases waveform measurements are often comparable to theoretical Green´s functions and a good understanding of the acquired waveforms is then very important, especially for highly anisotropic layers. This work deals with the dynamic 2D space-time response of an anisotropic plate to a transient line-force on the free surface, using the Cagniard-de Hoop method. Contrary to other methods that require either restrictive hypothesis such as, a high frequency content or a long distance propagation, or necessitate lengthy computation, the generalized ray theory, adopted in this work, is a very good candidate for obtaining exact solutions in the space-time domain without any restrictions and for a wide class of anisotropic materials