Analytical model for depth profiling using sonic IR NDE

Sonic IR NDE is a relatively new hybrid NDE technology which has been proven to be reliable and sensitive to detect flaws of different types in a variety of materials and structures. Despite the success this technology has achieved in detecting defects, little work has been devoted to characterizing defects quantitatively. In this study, we present a model that describes heat diffusion from subsurface defects in a composite material using Green's function procedure. The model is used to map some aspects of the temperature-time curve with a defect's depth, namely, half maximum power temperature point, the peak slope point, and the second derivative peak point. The model suggests that a relationship can be established to map a defect's depth to these features. The diversity of features allows the user to choose the feature that fits best the application of interest.