Analysis of the velocity-induced eddy current in MFL type NDT

In magnetic flux leakage (MFL) type nondestructive testing (NDT), there could be velocity-induced eddy currents during the sensing, which might cause the distortion of the defect signals. In this paper, the distortions of the sensing signals are analyzed by using three-dimensional finite-element analysis with velocity-induced eddy currents, and then, the compensation scheme of the signal distortion is presented to obtain the pure defect signals. The presented method has been verified by experimental measurement.