Three-Dimensional Simulation of Remote Field ECT using the Ar Method and a New Formula for Signal Calculation

Abstract
In this article, a three-dimensional (3D) edge-element finite element method (FEM) code of the Ar method is upgraded to enable the 3D simulation of remote field eddy current testing (RFECT) problem by introducing a new formula for the pickup signal calculation. The validity of the proposed formulation and the corresponding implementation are verified by comparing numerical results of the 3D code with the measured signals and those of an axisymmetric code. The numerical results show that, although both the conventional formulation and the proposed method are for a nonmagnetic tube, the upgraded code has a more satisfactory simulation accuracy for a tube of ferromagnetic material. It is also proven that the upgraded Ar-method code is very efficient in the 3D simulation of the RFECT problem and even a normal PC can accomplish the calculations.