Thickness Measurement of Multi-layered Structure by Eddy Current Testing

摘要

Based on the work of Luquire and Cheng, the impedance change model of a probe coil of rectangular cross section above a structure with an arbitrary number of parallel layers is studied. Following this model, the thickness measurement of multi-layered configurations is investigated and simulation programs are developed. The experimental eddy current detection system is developed and methods of the impedance measurements inversion are proposed. The agreement between calculated and observed values is within the limits of experimental error and the results show that the forward model and inverse techniques studied in this paper are feasible and reasonable.