Detection and Reconstruction of Rolling Contact Fatigue Cracks Using Eddy Current Pulsed Thermography

Abstract

Eddy current pulsed thermography (ECPT) as one of the emerging nondestructive techniques has been recently used for defect evaluation in the rail track. This paper focuses on detecting and reconstructing the rolling contact fatigue (RCF) cracks in a cut-off rail track specimen. Specifically, two features extracted from the maximum thermal rise and gradient of first differential thermal results are used to quantify the pocket length and the angle of RCF cracks. Based on these quantitative results, the reconstructed parameters of the RCF cracks are further compared with the X-ray CT result. Results show that ECPT has the advantage of indirectly presenting the 3D parameters of the crack without the specimen size influence. However, the accuracy and reliability of the reconstructed results depend on the position of the crack (edge effect), the thermal pattern of different defects, and the performance of the IR camera.