UC Davis

Evaluating damage progression in fiber-reinforced polymeric composite structures is critical for effective condition-based monitoring techniques of these structures. In this study, three sets of woven fiberglass/epoxy specimens were investigated under axial loading and unloading conditions using embedded and surface-mounted piezoelectric wafers. The noisy ultrasonic waveforms were denoised and analyzed with Gabor wavelet transforms and their contour plots, in particular normalized contour perimeters. It was found that the trend of the selected contour parameters captures the specimens' strain reasonably well in some samples, replicating loading, unloading and residual strain. This technique shows promise for tracking damage progression, residual strains, and pending failure in fiber-reinforced polymeric composites.