Ultrasonic monitoring of the dynamic properties of composites during manufacture

Ultrasonic techniques were used to directly monitor the changes in the rheological properties of polymer matrix composites throughout the cure cycle. These measurements were performed during processing using piezoelectric transducers designed to operate at elevated temperatures inside the autoclave. Measurements of the amplitude and velocity of the longitudinal were made periodically throughout the cure cycle. Dynamic properties of the composite were determined from these measurements. Results are compared with mechanical property measurements using conventional rheological characterization techniques to establish the validity of the approach