Measurement of delamination size and depth in ceramic matrix composites using pulsed thermal imaging

A pulsed thermal imaging (PTI) method was developed to determine the size and depth of delaminations in ceramic matrix composites (CMCs). In this method, pulsed heat energy is applied to the surface of a sample, and the decay of the surface temperature is then measured and analyzed to produce a depth image of the sample. The sensitivity and accuracy of the PTI method were determined from experiments using a melt-infiltrated CMC sample with drilled flat-bottom holes at the back surface to serve as "delaminations". A 3-D transient-heat-transfer code was used to simulate the experimental heat transfer process within the samples and to determine the optimal sensitivity for delamination detection by the PTI method.