Numerical Model of Eddy Current Inspection with DC Magnetic Field Associated

Abstract

Most non-destructive techniques can be well represented in a virtual environment, in particular, eddy current testing (ECT) simulation is a useful and well-established tool to predict and represent real inspection situations permitting testing customization in a fast, cheap and efficient way. Conventional ECT generally works with low-intensity magnetic fields, however, for advanced variations of the technique, where external DC magnetic fields can be applied to locally decrease the magnetic permeability, there is no Finite Element Method (FEM) packages available to deal with such nonstandard model. Many authors [1] and [2] have presented this ECT solution for different industrial applications using external DC magnetization to carry nonlinear ferromagnetic materials to the saturation level of the magnetization curve to increase the ECT depth penetration. In general, ECT modelling calculation is benefited by properties of steady-state regime where all magnetic fields are oscillating at the same frequency not permitting through multi-frequency calculation. The present work proposes a simulation solution for such a case where DC magnetic field is associated with ECT. A theoretical model is presented together with experimental results validation.