Impedance and mesh structure considerations in the finite element analysis of Eddy current NDT probe phenomena

Differential eddy current probes are used in the nondestructive testing of steam generator tubing for the detection and characterization of defects in the tube wall. Axisymmetric finite element code has been developed to study the associated electromagnetic field/defect interaction phenomena. Alternative forms of probe impedance calculations are examined in this paper together with the effects of mesh structure on the finite element prediction of probe impedance plane trajectories.