Characterization of Angular RCF Cracks in a Railway Using Modified Topology of WPT-Based Eddy Current Testing

Unavoidably, rolling contact fatigue (RCF) causes natural crack formation in the railhead, leading to rupture. Eddy current testing (ECT) is commonly used to quantify RCF cracks because of its higher sensitivity to a surface flaw, though with limited feature points. This article aims to characterize inclined angular RCF crack parameters in a rail-line material via a modified topology of Wireless Power Transfer (WPT)-based ECT (WPTECT) due to its magnetically coupled resonant for excitation and sensing circuits and utilize multiple resonance responses compared to other ECT. We experimentally designed and evaluated WPTECT and extracted multiple resonances and principal components analysis features to characterize inclined angular RCF cracks. The response minima point feature quantified the crack parameters incomparably; however, the second resonance feature is better than the first resonance. The reconstructed depth, opening width, and angle of the RCF cracks have a maximum correlation, R
²
value of 96.4%, 93.1%, and 79.1%, respectively, and root mean square error of 0.05 mm, 0.08 mm, and 6.6°, respectively.