Application of laser generated ultrasound for evaluation of internal defects in carbon/PPS composites

摘要

The aim of this study is to develop non-contact and real time inspection technique based on laser generated ultrasound for evaluating defects such as void, delamination in CFRP composite fabricated from recently developed 3-dimensional fiber placement system (FPS). Fiberized Nd; YAG pulse laser is used to generate ultrasonic guided wave in the unidirectional Carbon/PPS specimen. The laser generation of narrowband ultrasound is achieved through a linear slit array. Receiving angle of air-coupled transducer is optimized by changing angle of it. The system has proven sensitive to defects in composite materials, and is well suited for on-line process control applications, with standoff distance for the transmitter and receiver, while retaining single-shot operation.