Calculation of eddy-current probe signal for a 3D defect using global series expansion

Abstract

Purpose -The purpose of this paper is to present a novel eddy-current modeling technique of volumetric defects embedded in conducting plates. This problem is of great interest in electromagnetic non-destructive evaluation and has already been exhaustively studied. Design/methodology/approach -The defect is modeled by a volumetric current dipole density which satisfies an integral equation. The latter is solved by the classical method of moments. The authors propose the use of globally defined, continuous basis functions for the expansion of the current dipole density. Findings -The proposed global expansion provides an improvement of the numerical stability and the performance of the simulation, over classical approaches. The proposed method is tested against both measured and synthetic data obtained by a different defect model. Originality/value -The new discretisation scheme -in contrast to the classical approaches -does not need the discretisation of the defect volume. This involves numerous advantages that are discussed in the paper.