Simulation on quantitative analysis of crack inspection by using eddy current stimulated thermography

Eddy current (EC) stimulated thermography has been proven to be an emerging integrative nondestructive approach for detecting and characterizing surface and subsurface cracks. In this paper, numerical simulation study has been conducted to understand EC stimulated thermography for defect inspection on metallic sample. It has been investigated that transient EC distribution and heating propagation for cracks with different lengths and depths. The simulations are carried out by using AC/DC module of COMSOL mul-tiphysics software. Image processing technique is proposed to analyze the thermal images obtained during the heating and cooling period of the inspection process. The proposed approach is proved to be capable of tracking the heat diffusion by processing the images sequentially. Understanding of transient EC distribution and heating propagation is the fundamental of quantitative nondestructive evaluation of crack inspection with EC stimulated thermography.