Resistance to impact damage is extremely important for most composites. Such damage can initiate delamination, one of the most common failure modes in composites.. Because this is such an important failure mode, many studies have tried to develop matrix resins and composite designs that are more resistant to impact. Such studies have been hampered by the difficulty in quantifying impact damage non-destructively. Optical coherence tomography (OCT) can address this issue for glass and Kevlar reinforced systems. One way to evaluate the success of any new technique is to compare it to an existing one. In this work, OCT will be compared to laser scanning confocal microscopy.OCT is a confocal technique that is enhanced by interferometric rejection of out-of-plane image scattering. Briefly, OCT uses a low coherence source such as a superluminescent diode laser with a fiber optic based Michelson interferometer. In this configuration, the composite is the fixed arm of the interferometer and the fiber optic acts as the confocal aperture. Reflections from heterogeneities within the sample are mapped as a function of thickness for any one position. Volume information is generated by translating the sample on a motorized stage. Quantitative information about the location and size of a feature within the composite is obtained.
Proceedings Title: Adhesion Society, Annual Meeting | 23rd | | Adhesion Society
Conference Dates: February 20-23, 2000
Conference Location: Blacksburg, VA
Conference Title: Proceedings of the Annual Meeting - Adhesion Society
Pub Type: Conferences
composites, confocal microscopy, damage, impact, non-destructive evaluation, optical coherence tomography