Propagation parameters of ultrasonic waves in polymer composites

The non-contact ultrasonic technique of wave generation was
used to test polymer composites. Transient elastic waves were generated with a
Nd:YAG pulsed laser. Measurements aiming at the determination of the macroscopic
parameters of propagation of bulk waves (amplitude, velocity and frequency
distribution) were made in a unidirectional glass/epoxy (GFC) and isotropic
polyvinyl chlorid plastic (PVC) thick plate. The influence of a constrained
surface on the ultrasound parameters is discussed. The variations of the
macroscopic parameters of propagation as functions of distance from the
epicentrum were studied. PZT-ceramic standard ultrasound probes were used as
receiver.