Equivalent current models and the analysis of directional ECT signals
Weiying CHENG1
1 NDE Center, Japan Power Engineering and Inspection Corporation, 14-1, Benten-cho, Tsurumi-ku, Yokohama 230-0044, Japan
Abstract
Eddy current testing was studied from both the ‘transmission’ and ‘receiving’ sides. The distributions of eddy current and magnetic field were analyzed, and the defect-induced eddy current perturbation was modeled by equivalent current models, permitting qualitative interpretation of each directional magnetic field signals. Investigation also showed that the signals resulting from the bypassing of eddy currents under a crack are appropriate for depth sizing and that from the bypassing to a crack's longitudinal ends are appropriate for length sizing. The accuracy of defect sizing can be improved by using the combination of multi-directional magnetic field signals.
Keywords
eddy current testing, magnetic field, equivalent current model, sizing, cracks
Full Paper:PDFEJAM Vol.7 No.2 pp.179-188 "Equivalent current models and the analysis of directional ECT signals"