Eddy Current Analytical Calculation Under Low Frequency AC Excitation

The paper deals about the simulation of linear and non-linear eddy current (EC) techniques in the commercial 3MA NDT systems. Robust analytical computation is established to investigate the properties of bilayer specimens. In non-linear EC, the quasi-static magnetic behaviour is described via the Jiles-Atherton model. In order to take into account the dynamic phenomena, the model is extended to Berttoti formula. Based on electromagnetic meso-macroscopic behaviour, the experimental signals are accurately reproduced. The impact of frequencies and surface layer thickness are analysed experimentally and numerically.