Analytical modelling of eddy current response from driver pick-up coils on multi-layered conducting plates

Abstract

A driver pick-up probe possesses better sensitivity and flexibility due to individual optimisation of its coils. It is preferred for sophisticated applications, such as an eddy current array probe. In this study, a non-coaxial cylindrical driver pick-up probe above a multi-layered conducting plate has been analytically modelled with coordinate transformation for eddy current non-destructive evaluation. The reflection and transmission theory of electromagnetic fields is adopted to derive the generalised reflection coefficient for a layered plate, which measures the relationship between the primary and secondary eddy current fields. The calculated values from the resultant model indicate good agreement with those from the finite element model and experiments.