Cure Monitoring of Glass Fibre-Epoxy Resin Composites Using Ultrasonic Techniques

This paper describes the possibility of using ultrasonic waves to determine the fill-front and extent of cure monitoring of composite material during curing. For this work, the Vacuum Assisted Resin Transfer Moulding (VARTM) process prepares the material Glass Fibre-composite. Here, two methods are explored separately to monitor the cure and fill the front. In the first method, bulk ultrasonic waves in pulse-echo mode and the reflected signal from the back wall are used to monitor the curing process. The difference between the empty and filled mold just after infusion showed that the fill front during the curing process with respect to ultrasonic wave behavior further, the ultrasonic signals’ attenuation with time is studied as the resin’s material properties change while the curing reaction occurs. We can observe clear trends for identifying the progress of the curing reaction. The second method used a thin wire waveguide. A longitudinal guided wave transmitted/received in the waveguide, and as before, changes between dry mold and just after the infusion is studied. The difference in reflected signals’ strength can observe in that the fill-front, either in dry mold or the resin, reaches the region of interest during curing. Also, both bulk and guided wave signals’ amplitude are monitored continuously as a function of time for studying the progress of cure based on the attenuation of these signals.