Automated Guided Wave System for In-Process Cure Monitoring of CFRP Composite Laminates

In the polymer composites industry, cure cycles are typically developed from trial-and-error or a more effective processing science approach to reduce the final porosity level in the composite laminate. Using a guided wave-based in-process cure monitoring technique for carbon fiber reinforced polymer (CFRP) composites, high-temperature piezoelectric transducers were utilized to interrogate a 24-ply unidirectional composite panel fabricated from Hexcel IM7/8552 prepreg during cure. It was shown that the amplitude of the guided wave increased sharply around vitrification, and the time of arrival (TOA) curve possessed an inverse relationship with degree of cure.