Semi-Analytical Computation of a Quasi-Static Field Induced by a 3-D Eddy Current Probe in Anisotropic Material With Rough Interfaces

This article presents a numerical model dedicated to the computation of a quasi-static field induced by a 3-D eddy current probe in unidirectional composite material presenting delamination. The specimen is homogeneously anisotropic and the flaw is represented by a local deformation in the planar geometry. The curvilinear coordinate method (CCM) is used to solve Maxwell's equations in covariant form. Based on the Fourier modal method, the semi-analytical approach consists of presenting the electromagnetic field components as eigenmode expansion in a new non-orthogonal coordinate system fitting the geometrical perturbation. Then, interface conditions can be analytically included in order to evaluate the unknown amplitude of eigenmodes. To take into account the contribution of lower interfaces, a recursive and stable scattering matrix algorithm is implemented. The numerical validation shows a good agreement between simulation results and finite element (FE) data.