Impact damage detection and characterization using eddy current pulsed thermography

Reciprocating impact load leads to plastic deformation of the metal, which will cause fatigue and cracks. Due to the complex surface condition and various types of damage, it is difficult to extract the feature of nature micro cracks by using common thermograph NDT methods. This paper presents the feasibility study of using eddy current pulse thermography for detecting impact damages of torque arm in aircraft brake system. The optical flow algorithm is used to characterize the thermal diffusion and extract the transient thermal behavior among impact areas under the complex background noise. In addition, the spatial-transient pattern analysis is hybrid to automatically detect the nature cracks. Experiment study has been conducted and the magnetic particle is presented to validate the proposed method.