3-D Finite Element Modeling of the Remote Field Eddy Current Effect
Differences between conventional single frequency eddy current (EC) nondestructive testing (NDT) and remote field eddy current (RFEC) NDT are summarized schematically in Fig. 1. In the testing of steam generator tubing, a differential probe (Fig. la) is used to produce impedance plane trajectories (Fig. lc) which are indicative of the tubes condition. From a numerical simulation or modeling point of view, the finite element (FE) prediction of such impedance plane trajectories [1-3] requires a geometry of the dimensions shown in Fig. le. The relatively small mesh sizes associated with the FE simulation of EC probe behavior are a distinct advantage in that only modest computer resources are required. Indeed, for axisymmetric geometries, such code can run on a personal computer.