An investigation of the effects of material anisotropy andheterogeneity on pulsed, laser-generated acoustic signals

摘要

Point-source and line-source models for the laser ultrasonicnsource in materials exhibiting transverse isotropy are applied to thenspecific problem of laser generation and ultrasonic propagation innunidirectional, polymer matrix composite materials. Comparing experimentnand theory, it is shown that these composite materials exhibitnhomogeneous behavior, at the frequencies investigated, for ultrasonicnwave propagation perpendicular to the fiber direction. For ultrasonicnpropagation in the fiber direction, ultrasonic dispersion, resultingnfrom the inhomogeneous nature of the composite, affects the lasernultrasonic signal