Modelisation of thin cracks with varying conductivity in eddy‐current testing

In the ideal crack model (negligible thickness and an impenetrable barrier to electric current) in eddy‐current testing frame, the field‐flaw is equivalent to a current dipole layer on its surface. This dipole density is the solution of an integral equation with a hyperstrong kernel. This model has shown its efficiency, as well the computing accuracy, as for the CPU time. Furthermore, the case of a current leakage across crack was considered by introducing an equivalent conductivity of the crack. This paper aims at simulating a local varying conductivity. In particular, we focus on a constant piecewise conductivity. In this last case, because of the presence of the hypersingular kernel in the equation, the numerical scheme using the ideal case has to be modified.