Low velocity impact damage evaluation in fiber glass composite plates using PZT sensors

In this work PZT sensors are proposed to characterize the impact effects in fiber glass composite plates. To provide effective and reliable results the analysis was accomplished on samples submitted to multiple impacts, then guaranteeing the same testing conditions for different impact levels. The analysis of the impact effect has been made by two parameters; amplitude response and time shift. PZT sensors have been bonded to the samples in a pitch-and-catch configuration and the Lamb wave symmetrical mode (S0) signal was used. The results demonstrate that the two evaluated parameters are able to characterise the different damage types occurring in these composites, as well as to evaluate their severity. It was also observed that amplitude predict well the defect size, whenever fiber-breakage occurs.