Study on Characteristics of Pulsed Eddy Current Field of Copper Belt Detection

Abstract

Abstract. In order to effectively represent the mechanism of pulsed eddy current testing, the analytical model of harmonic eddy current field above copper strip and plate is worked out in cylindrical coordinate by applying the theory of reflection and transmission of electromagnetic waves and Truncated Region Eigenfunction Expansion method. By Fourier transform of the unit square-wave pulse, analytical model of the pulsed eddy current field is derived, as well as the impedance model and response model of eddy current probe. Those models are simulated by using Mathematical and Comsol, and the relationship is sum up which eddy current probe's impedance and induced voltage vary with thickness, lift-off height, excitation frequency，thus the correctness of analytical model of pulsed eddy current field is validated.