Inversion of thicknesses of multi-layered structures from eddy current testing measurements.
Luquire et al.'s impedance change model of a rectangular cross section probe coil above a structure with an arbitrary number of parallel layers was used to study the principle of measuring thicknesses of multi-layered structures in terms of eddy current testing voltage measurements. An experimental system for multi-layered thickness measurement was developed and several fitting models to formulate the relationships between detected impedance/voltage measurements and thickness are put forward using least square method. The determination of multi-layered thicknesses was investigated after inversing the voltage outputs of the detecting system. The best fitting and inversion models are presented.
Huang
Ping-jie
PJ
Institute of Advanced Manufacturing Engineering,Zhejiang University, Hangzhou 310027, China. vamadis@yahoo.com.cn
Wu
Zhao-tong
ZT
D000465:Algorithms; D003198:Computer Simulation; D003238:Connective Tissue / Q000502:physiology*; D017097:Electric Impedance; D004574:Electromagnetic Fields; D009716:Numerical Analysis, Computer-Assisted; D011846:Radio Waves