Improving the Accuracy of Finite Element Modeling of a High-Frequency Eddy Current Probe

The paper considers the issues of finite element modeling of an eddy current probe designed to measure the thickness of a dielectric coating on an electrically conductive non-magnetic base metal. The quality criteria of the model are formulated and the requirements for them are presented: the precision and error of calculating the signals of the finite element model of an eddy current probe should not exceed ±(0.001h + 0.1) microns when the thickness h of the coating changes. To achieve this task, an analysis of the parameters affecting precision and error was carried out, the criteria for their assessment were justified and an approach to the problem of increasing the frequency of the finite element grid in critical places of the finite element model was formulated. To confirm the achieved characteristics, a real eddy current probe was manufactured, its characteristics were evaluated using a coating thickness simulator machine and measures of specific electrical conductivity. An algorithm for calibrating the signals of a real eddy current probe is presented, which is used to validate a finite element model.