Publications

Comparative study of non-destructive damage evaluation methodologies for CFRP low velocity impact damage

Loyola, Bryan R.; Loh, Kenneth J.; Saponara, Valeria L.; Chen, John C.; Briggs, Timothy B.

Damage evaluation for fiber-reinforced polymer composites has been a topic of interest for more than 30 years, and for good reason. With damage modes significantly different than monolithic alloys, engineers have had to design composite structures to tolerate delamination, fiberbreakage, matrix cracking, and fiber-matrix debonding. Accomplishment of this goal has required understanding how and why these damage modes manifest themselves and grow to critical levels, even when the damage is barely visible from the surface. To this end, many nondestructive evaluation techniques have been developed, each with their advantages and disadvantages to characterize these damage forms. In this study, a series of non-destructive evaluation techniques are performed and evaluated on a set of damaged carbon fiber reinforced plastic (CFRP) specimens that have been subjected to varying levels of incident kinetic energy from low velocity impact (LVI). Specifically, 3-D x-ray computed tomography (CT), active thermography, electrical impedance tomography (EIT), and vibrothermography have been systematically utilized for evaluation of the specimens. The advantages and disadvantages are thoroughly explored and reported for each method in order to gain insight into the limitation of each of the damage detection methods and the damage morphology resulting from LVI.