Coupling t-ϕ formulation with surface impedance boundary condition for eddy current crack detection

¹ Cedrat S.A. 15, Chemin de Malacher, 38246 Meylan Cedex, France
² Laboratoire de Génie Électrique de Grenoble, G2Elab, UMR 5269 INPG-UJF-CNRS, ENSIEG –, BP 46, 38402 Saint-Martin-d'Hères Cedex, France

Corresponding authors: Christophe.Guerin@cedrat.com Gerard.Meunier@g2elab.inpg.fr Fabrice.Foucher@cedrat.com

Received: 14 December 2009
Revised: 18 March 2010
Accepted: 22 March 2010
Published online: 21 October 2010

Abstract

We present in this paper a 3D electromagnetic formulation to describe two conductors in electric contact with each other, submitted to the field of a coil in which an AC current is flowing. One of the two conductors is described by the t-ϕ formulation, the other conductor is described by the surface impedance boundary condition. The proposed coupled formulation has been validated with a numerical example with a simple geometry. This coupled formulation has then been applied to a numerical example on which a crack has to be detected. It is composed of a non magnetic tube embedded in a thick steel tube sheet, submitted to the field of a coil.