The fast computation of eddy current distribution and probe response in homogenized composite material based on semi-analytical approach

Abstract

Due to the excessive use of composites in the industrial field, many numerical modeling approaches dedicated to the characterization of such complex material by means of Non Destructive Testing Techniques were developed. In this paper, we present a numerical model dedicated to simulate the inspection of unidirectional Carbon Fiber Reinforced Polymer using Eddy Current technique for detecting fiber disorientation. A semi-analytical model based on a modal approach is developed for the fast computation of quasi-static field induced by an arbitrary 3D Eddy Current probe in the material. Because of the high anisotropy and strong heterogeneity of such material, a prior phase of homogenization is assumed and the material is then considered as homogeneously anisotropic. The modal approach consists in resolving Maxwell’s equations in the Fourier domain. Therefore, the electromagnetic field is expressed as a sum of eigen-modes. To take into account the wave propagation through the multilayered structure and boundary conditions at each separating interface, a stable and recursive scattering matrix algorithm has been implemented. The impedance of the probe is computed analytically using Auld’s formula in orders to identify the main orientation of the fibers in the inspected zone. For numerical validation, simulated data provided by the model are compared to finite element data.