Fast computation of the response of any 3D Eddy Current probe scanning a 3D stratified conductor characterized by a set of arbitrary interfaces of complex shape

Abstract

This paper concerns the development of a semi-analytical model dedicated to the fast computation of the response of a 3D Eddy Current (EC) probe scanning a planar conductor of complex shape. The workpiece is characterized by a finite number of complex interfaces k, 1 ≤ k ≤ N, each one being defined by any 2D arbitrary surface a _k(x, y). A previous semi-analytical model based on the Curvilinear Coordinate Method (CCM) has been presented for the computation of quasi-static fields induced by any 3D EC probe scanning a half-space of complex shape. This paper gives a natural extension of this preliminary work. CCM consists in introducing a change of coordinates in order to be able to write analytically and easily boundary conditions separating two media. No mesh is needed, nevertheless, the covariant form of Maxwell’s equations is required due to a novel generalized metric space. Boundary conditions at multiple interfaces are efficiently implemented thanks to the S-matrix algorithm. Finally, some numerical experiments show the validity of the numerical model by some comparison between simulated data obtained by a FE commercial code and those provided by the proposed numerical model.

Keywords

Covariant form of Maxwell’s equations eddy current simulation Eddy current nondestructive testing

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