3D modeling of pulsed thermal NDT: Back to basic features and subtle phenomena

Abstract

By using advanced 3D modeling of thermal nondestructive testing (TNDT) problems, most of basic TNDT features are shortly described, but the emphasis is put on the analysis of some subtle physical phenomena which may be observed in TNDT experiments, and most of them have not been properly reflected in the earlier studies. These are: 1) the “smashing” of 2D defect surface “footprints” because of 3D heat diffusion, 2) practical approaches to determining defect lateral size by their surface temperature indications, 3) clarification of a limiting defect size/depth ratio providing reliable detection of subsurface defects; 4) inversion of “classical” temperature signals at longer times, 5) defect shading, 6) influence of composite anisotropy on defect detectability, and 7) combined heating/cooling allowing to govern behavior of surface temperature profiles.