ANISOTROPIC LAYER CHARACTERIZATION USING PHASE VELOCITIES OF ULTRASONIC BULK WAVES GENERATED AND DETECTED WITH LASERS

摘要

A non-contact laser-ultrasonic technique is described that allows the determination of stiffness properties of an anisotropic layer bounded to a substrate. The method requires access to only one side of the structure. Plane waves are synthesized by scanning the surface with a laser line source at judiciously chosen intervals. By doing so, the intricacies associated with the reflection of an acoustic ray off the interface between the anisotropic media are avoided. The identification of the stiffness-tensor components is based on the inversion of the phase velocities of these reflected plane waves.