Non-destructive evaluation of carbon fiber-reinforced laminated composites.

Fiber-reinforced composites offer a high strength to weight ratio alternative to metal components, such as aluminum and steel, but final part properties rely heavily on the manufacturing process. In this study, two non-destructive evaluation methods are developed and applied to carbon fiber reinforced laminated composites. First, a finite element thermal structural model was developed in COMSOL Multiphysics to predict the displacements and internal stresses associated with the final part. The predicted results were compared with experimental measurements and had a mean integrated average percent relative error of 6.48%. The second non-destructive evaluation method is a patent pending ultrasonic C-scanning technique using a spherically focused, high frequency transducer. The scan results are input to a custom Matlab program where the ply thickness, ply type and orientation are determined for each lamina in the stacking sequence. Based on comparison with known ply stacking sequences, the ply detection algorithm is 90-95% accurate.