Lu, M.; Meng, X.; Huang, R.; Chen, L.; Peyton, A.; Yin, W. A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor. NDT & E International, 2021, 123, 102519. https://doi.org/10.1016/j.ndteint.2021.102519.
Lu, M.; Meng, X.; Huang, R.; Chen, L.; Peyton, A.; Yin, W. A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor. NDT & E International, 2021, 123, 102519. https://doi.org/10.1016/j.ndteint.2021.102519.
Lu, M.; Meng, X.; Huang, R.; Chen, L.; Peyton, A.; Yin, W. A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor. NDT & E International, 2021, 123, 102519. https://doi.org/10.1016/j.ndteint.2021.102519.
Lu, M.; Meng, X.; Huang, R.; Chen, L.; Peyton, A.; Yin, W. A High-Frequency Phase Feature for the Measurement of Magnetic Permeability Using Eddy Current Sensor. NDT & E International, 2021, 123, 102519. https://doi.org/10.1016/j.ndteint.2021.102519.
Abstract
Electromagnetic sensing has been used for diverse applications of non-destructive testing, including the surface inspection, measurement of properties, object characterization. However, the measurement accuracy could be significantly influenced by the lift-off between sensors and samples. To address the issue caused by lift-offs, various strategies have been proposed for the permeability measurement of ferromagnetic steels, which mainly involves different sensor designs and signal features (e.g., the zero-crossing feature). In this paper, a single high-frequency scenario for the permeability retrieval is introduced. By combining the signal of two sensing pairs, the retrieval of magnetic permeability is less affected by the lift-off of sensors. Unlike the previous strategy on reducing the lift-off effect (directly taking the phase term out of the integration) using the Dodd-Deeds analytical method, the proposed method is based on a high-frequency linear feature of the phase term. Therefore, this method has the merit of high accuracy and fast processing for the permeability retrieval (a simplified version of Dodd-Deeds analytical formulas after the integration). Experimental measurement has been carried out on the impedance measurement of designed sensors interrogating ferromagnetic dual-phase steels. For sensor lift-offs of up to 10 mm, the error of the permeability retrieval is controlled within 4 % under the optimal frequency.
Keywords
electromagnetic sensing; lift-off; eddy current; magnetic permeability; non-destructive testing
Subject
Engineering, Automotive Engineering
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
