In-situ Monitoring of Carbon Fiber Laminate Curing using Interface Reflection Power from Pulse-Echo Ultrasound

Abstract

Nondestructive testing is used for carbon fiber laminates to identify defects in the laminate post manufacturing; however, the present study uses it to monitor the curing process of a carbon fiber laminate during manufacture. In this work pulse-echo ultrasound is used to monitor the cure cycle for a thermoset resin and carbon fiber laminate. During the cure, the speed of sound through the material, amplitude of the reflection at different interfaces, and power of the reflection are quantified. Then, the resin is studied using rheology to find the viscous profile over time. Finally, the ultrasound parameters are related to the material parameters from the rheological profile. Results show a one-to-one relationship between the speed of sound and the degree cure of the resin, suggesting that the proposed technique may be used to quantify the degree of cure for a composite during the manufacturing process.