Determination of flaw size from thermographic data

William P. Winfree, Patricia A. Howell, Joseph N. Zalameda
Conventional methods for reducing the pulsed thermographic responses of delaminations tend to overestimate the size of the flaw. Since the heat diffuses in the plane parallel to the surface, the resulting temperature profile over the flaw is larger than the flaw. A variational method is presented for reducing the thermographic data to produce an estimated size for the flaw that is much closer to the true size of the flaw. The size is determined from the spatial thermal response of the exterior
more » ... urface above the flaw and a constraint on the length of the contour surrounding the flaw. The technique is applied to experimental data acquired on a flat bottom hole composite specimen.
doi:10.1063/1.4914621 fatcat:ozfgqhaaxjf23hvsrc6x262eny