A Domain Decomposition Finite-Element Method for Eddy-Current Testing Simulation

A typical eddy-current testing (ECT) process involves scanning of conducting test sample using an EC probe, which can be an air-core coil or ferrite-core coil. Its accurate and efficient modeling is critical to probe and testing parameter optimization. The finite-element method (FEM) has been widely used in ECT simulation. Unfortunately, the conventional FEM is cumbersome and inefficient when the movement of a ferrite-core coil is to be considered, because the change of the coil position results in repetition of meshing as well as generating and preconditioning matrix equation. In this paper, we resolve the problem by dividing the solution domain into subdomains. The test sample and the ferrite core are assigned to different subdomains, and each subdomain is meshed independently. The excitation coil is not included in a subdomain, and its contributions to the magnetic fields in both subdomains are calculated analytically. Solutions of the subdomains are coupled by calculating the contribution of the induced current or magnetization current in a subdomain to the magnetic field in the other subdomain. The proposed method has the merits of easy mesh generation and efficient and accurate solution.