An interaction between electromagnetic field and materials: Characterization of mechanical stress in ferromagnetic materials using Eddy currents non-destructive techniques
For more than thirty years the GeePs Laboratory has been working on the numerical simulation of electromagnetic systems through numerous research topics. During this conference, we propose to present a recent problem that has been addressed by the laboratory. This application concerns the use of Eddy Currents (EC) in non-destructive testing (NDT) to characterize the stress state of a ferromagnetic material. For this kind of material, the electromagnetic properties are modified under the effect of mechanical stresses. A "COMSOL Multiphysics" modeling was implemented to evaluate and to optimize the response of the sensor to EC signal according to a stress state. The modelling consists in including in a low frequency 3D electromagnetic finite element model a magnetomechanical constitutive law (here the multiscale model [Daniel and Galopin 2008], [Daniel 2013], [Dahia et al 2015]) by calling an external compiled C function. A nonlinear resolution is then necessary. The presence of regions with small skin thickness implies the use of a mix of different geometric elements in the 3D mesh.