Effect of frequency and phase setting in obtaining scanning guided waves in composite plates

In the paper are presented the results obtained by numerical simulations on composite plates, with arrays of transducers able to create guided waves by appropriate management of the signal delay and topology of the transducers. Appropriate generation of the Lamb waves, using an adequately shaped burst signal and frequencies corresponding to quasi non-dispersive modes, proved to be able to detect barely visible defects in composites. The avoidance of reflected signals offered conditions to have an easier analysis task in evaluating the transmitted and reflected waves produced by a guided wave which was scanning the plate or pipe type structure.