Cross-correlation technique for revealing defects in differential pulsed eddy current defectoscopy

Abstract

The utilization of the cross-correlation technique in pulsed eddy current testing is described and illustrated with an example of an artificial defect in an electrically conductive steel plate. The investigated eddy current probe is of a differential type, consisting of one excitation and two sensing coils with a ferrite magnetic circuit. The numerical solution is carried out in the COMSOL Multiphysics using Magnetic field and Electrical circuit modules. The results are verified by performing laboratory experiment. Important aspects of the cross-correlation in the pulsed eddy current testing are then analyzed and discussed.