Thickness Measurement of Laminated Structure Based on Harmonic Eddy Current Technology

Laminated structural materials are widely used in various fields, and the simultaneous measurement of the thickness of multilayer materials with different physical properties is a difficult problem. It has significant academic value to measure the thickness of multi-layer materials. This article aims at the synthetic fuel rod shell structure, and establishes a laminated conductive structure impedance model with non-conductive layer. The viability of measuring the thickness of non-conductive layer and conductive layer is verified by Comsol finite element simulation. The traditional eddy current method can measure the thickness of non-conductive layer. The analytical model of laminated structure can fit the thickness of conductive layer by measuring impedance. In the end, the impedance analytical model effectively reduces the influence of skin depth and lift off effect, the thicknesses of two layers of different materials are obtained, which provides a theoretical basis and a quick method for the thickness measurement of complex laminated structures.