Eddy current interaction with a thin-opening crack in a plate conductor

In eddy current testing (ECT), a thin-opening crack in a plate conductor is much frequently encountered, The eddy current held perturbation due to the crack may be described as the effect produced by an equivalent current dip ole layer located on its surface. The dipole density may be found by solvin g a boundary integral equation. In this paper, formulas of the electric dya dic Green's function for a limited thickness plate are derived. Following a moment method scheme, numerical predictions are made for Benchmark models of ECT for steam generator, step 2, The eddy current perturbations due to t he cracks are calculated, The probe impedance changes are also evaluated an d are compared with experiments, and good agreement is found.