Hope College Engineering Department Research Experiences for Undergraduates Summer 2007 Project Summary

This research investigated detecting impact damage in fiber-reinforced polymer composites through using thermal imaging. Material was removed from the center of small scale glass/epoxy laminates (approximately 22mm x 200mm x 2mm) to make them prone to delamination when loaded. These samples were subjected to fatigue loading at various percentages of the monotonic strength and thermal images were taken at multiple intervals during each experiment. A modified lock-in thermography procedure was used to determine the area of delamination. These data resulted in fatigue life plots in which the area of delamination was related to the number of loading cycles. Ultimately, a similar set of fatigue life curves will be developed for composite samples that have been subjected to impact damage. Thermal imaging results from the impact damaged samples can then be used to predict how long damaged samples will last under certain fatigue load conditions.