Jin, Z.; Meng, Y.; Yu, R.; Huang, R.; Lu, M.; Xu, H.; Meng, X.; Zhao, Q.; Zhang, Z.; Peyton, A.; et al. Methods of Controlling Lift-Off in Conductivity Invariance Phenomenon for Eddy Current Testing. IEEE Access, 2020, 8, 122413–122421. https://doi.org/10.1109/access.2020.3007216.
Jin, Z.; Meng, Y.; Yu, R.; Huang, R.; Lu, M.; Xu, H.; Meng, X.; Zhao, Q.; Zhang, Z.; Peyton, A.; et al. Methods of Controlling Lift-Off in Conductivity Invariance Phenomenon for Eddy Current Testing. IEEE Access, 2020, 8, 122413–122421. https://doi.org/10.1109/access.2020.3007216.
Jin, Z.; Meng, Y.; Yu, R.; Huang, R.; Lu, M.; Xu, H.; Meng, X.; Zhao, Q.; Zhang, Z.; Peyton, A.; et al. Methods of Controlling Lift-Off in Conductivity Invariance Phenomenon for Eddy Current Testing. IEEE Access, 2020, 8, 122413–122421. https://doi.org/10.1109/access.2020.3007216.
Jin, Z.; Meng, Y.; Yu, R.; Huang, R.; Lu, M.; Xu, H.; Meng, X.; Zhao, Q.; Zhang, Z.; Peyton, A.; et al. Methods of Controlling Lift-Off in Conductivity Invariance Phenomenon for Eddy Current Testing. IEEE Access, 2020, 8, 122413–122421. https://doi.org/10.1109/access.2020.3007216.
Abstract
Previously, a conductivity invariance phenomena (CIP) has been discovered – at a certain lift-off, the inductance change of the sensor due to a test sample is immune to conductivity variations, i.e. the inductance – lift-off curve passes through a common point at a certain lift-off, termed as conductivity invariance lift-off. However, this conductivity invariance lift-off is fixed for a particular sensor setup, which is not convenient for various sample conditions. In this paper, we propose using two parameters in the coil design – the horizontal and vertical distances between the transmitter and the receiver to control the conductivity invariance lift-off. The relationship between these two parameters and the conductivity invariance lift-off is investigated by simulation and experiments and it has been found that there is an approximate linear relationship between these two parameters and the conductivity invariance lift-off. This is useful for applications where the measurements have restrictions on lift-off, e.g. uneven coating thickness which limits the range of the lift-off of probe during the measurements. Therefore, based on this relationship, it can be easier to adjust the configuration of the probe for a better inspection of the test samples.
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.
