Error estimation of calculated ECT signal due to thin crack in a plate using a global approximation of the dipole density

Abstract

The accuracy of the calculation of the signal due to the interaction of an eddy current testing (ECT) probe and a thin crack in a plate is basically depending on the discretization of the boundary integral equation which is modelling the actual physical arrangement. In this paper a solution method is introduced, where global approximation functions are used for proper discretization of the equivalent dipole density on the thin crack surface in that integral framework. Among other items, emphasis is put on the evaluation and control of the resulting numerical error. Using such results the automated discretization of rectangularly-shaped thin cracks analysed by an ECT signal prediction software will be shown to become feasible.