Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing

Xiaobai Meng; Mingyang Lu; Wuliang Yin; Abdeldjalil Bennecer; Katherine J. Kirk

doi:10.1109/TIM.2020.3038289

Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing

Xiaobai Meng, Mingyang Lu, Wuliang Yin, Abdeldjalil Bennecer, Katherine J. Kirk

EEE - Academic & Research

The University of Northampton

Research output: Contribution to journal › Article › peer-review

Abstract

For the electromagnetic eddy current testing, various methods have been proposed for reducing the lift-off error on the measurement of samples. In this paper, instead of eliminating the measurement error caused by the lift-off effect, an algorithm has been proposed to directly measure the lift-off distance between the sensor and non-magnetic conductive plates. The algorithm is based on a sample-independent inductance (SII) feature. That is, under high working frequencies, the inductance is found sensitive to the lift-off distance and independent of the test piece under an optimal single high working frequency (43.87 kHz). Furthermore, the predicted lift-off distance is used for the thickness prediction of the non-magnetic conductive samples using an iterative method. Considering the eddy current skin depth, the thickness prediction is operated under a single lower frequency (0.20 kHz). As the inductance has different sensitivities to the lift-off and thickness, the prediction error of the sample thickness is different from that of the lift-off distance. From the experiments on three different nonmagnetic samples – aluminium, copper, and brass, the maximum prediction error of the lift-off distance and sample thickness is 1.1 mm and 5.42 % respectively at the lift-off of 12.0 mm.

Original language	English
Journal	IEEE Transactions on Instrumentation and Measurement
DOIs	https://doi.org/10.1109/TIM.2020.3038289
Publication status	Published - 24 Nov 2020

Keywords

Eddy current sensor
lift-off measurement
non-destructive testing
sample-independence
thickness measurement

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10.1109/TIM.2020.3038289

Electromagnetic Sensing Group
Peyton, A. (PI), Fletcher, A. (Researcher), Daniels, D. (CoI), Conniffe, D. (PGR student), Podd, F. (PI), Davidson, J. (Researcher), Anderson, J. (Support team), Wilson, J. (Researcher), Marsh, L. (PI), O'Toole, M. (PI), Watson, S. (PGR student), Yin, W. (PI), Regan, A. (PGR student), Williams, K. (Researcher), Rana, S. (Researcher), Khalil, K. (PGR student), Hills, D. (PGR student), Whyte, C. (PGR student), Wang, C. (PGR student), Hodgskin-Brown, R. (PGR student), Dadkhahtehrani, F. (PGR student), Forster, S. (PGR student), Zhu, F. (PGR student), Yu, K. (PGR student), Xiong, L. (PGR student), Lu, T. (PGR student), Zhang, L. (PGR student), Lyu, R. (PGR student), Zhu, R. (PGR student), She, S. (PGR student), Meng, T. (PGR student), Pang, X. (PGR student), Zheng, X. (PGR student), Bai, X. (PGR student), Zou, X. (PGR student), Ding, Y. (PGR student), Shao, Y. (PGR student), Xia, Z. (PGR student), Zhang, Z. (PGR student), Khangerey, R. (PGR student) & Lawless, B. (Researcher)
1/10/04 → …
Project: Research

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@article{078d0335b9d5476c8503b20bef4f4638,

title = "Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing",

abstract = "For the electromagnetic eddy current testing, various methods have been proposed for reducing the lift-off error on the measurement of samples. In this paper, instead of eliminating the measurement error caused by the lift-off effect, an algorithm has been proposed to directly measure the lift-off distance between the sensor and non-magnetic conductive plates. The algorithm is based on a sample-independent inductance (SII) feature. That is, under high working frequencies, the inductance is found sensitive to the lift-off distance and independent of the test piece under an optimal single high working frequency (43.87 kHz). Furthermore, the predicted lift-off distance is used for the thickness prediction of the non-magnetic conductive samples using an iterative method. Considering the eddy current skin depth, the thickness prediction is operated under a single lower frequency (0.20 kHz). As the inductance has different sensitivities to the lift-off and thickness, the prediction error of the sample thickness is different from that of the lift-off distance. From the experiments on three different nonmagnetic samples – aluminium, copper, and brass, the maximum prediction error of the lift-off distance and sample thickness is 1.1 mm and 5.42 % respectively at the lift-off of 12.0 mm.",

keywords = "Eddy current sensor, lift-off measurement, non-destructive testing, sample-independence, thickness measurement",

author = "Xiaobai Meng and Mingyang Lu and Wuliang Yin and Abdeldjalil Bennecer and Kirk, {Katherine J.}",

year = "2020",

month = nov,

day = "24",

doi = "10.1109/TIM.2020.3038289",

language = "English",

journal = "IEEE Transactions on Instrumentation and Measurement",

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T1 - Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing

AU - Meng, Xiaobai

AU - Lu, Mingyang

AU - Yin, Wuliang

AU - Bennecer, Abdeldjalil

AU - Kirk, Katherine J.

PY - 2020/11/24

Y1 - 2020/11/24

N2 - For the electromagnetic eddy current testing, various methods have been proposed for reducing the lift-off error on the measurement of samples. In this paper, instead of eliminating the measurement error caused by the lift-off effect, an algorithm has been proposed to directly measure the lift-off distance between the sensor and non-magnetic conductive plates. The algorithm is based on a sample-independent inductance (SII) feature. That is, under high working frequencies, the inductance is found sensitive to the lift-off distance and independent of the test piece under an optimal single high working frequency (43.87 kHz). Furthermore, the predicted lift-off distance is used for the thickness prediction of the non-magnetic conductive samples using an iterative method. Considering the eddy current skin depth, the thickness prediction is operated under a single lower frequency (0.20 kHz). As the inductance has different sensitivities to the lift-off and thickness, the prediction error of the sample thickness is different from that of the lift-off distance. From the experiments on three different nonmagnetic samples – aluminium, copper, and brass, the maximum prediction error of the lift-off distance and sample thickness is 1.1 mm and 5.42 % respectively at the lift-off of 12.0 mm.

AB - For the electromagnetic eddy current testing, various methods have been proposed for reducing the lift-off error on the measurement of samples. In this paper, instead of eliminating the measurement error caused by the lift-off effect, an algorithm has been proposed to directly measure the lift-off distance between the sensor and non-magnetic conductive plates. The algorithm is based on a sample-independent inductance (SII) feature. That is, under high working frequencies, the inductance is found sensitive to the lift-off distance and independent of the test piece under an optimal single high working frequency (43.87 kHz). Furthermore, the predicted lift-off distance is used for the thickness prediction of the non-magnetic conductive samples using an iterative method. Considering the eddy current skin depth, the thickness prediction is operated under a single lower frequency (0.20 kHz). As the inductance has different sensitivities to the lift-off and thickness, the prediction error of the sample thickness is different from that of the lift-off distance. From the experiments on three different nonmagnetic samples – aluminium, copper, and brass, the maximum prediction error of the lift-off distance and sample thickness is 1.1 mm and 5.42 % respectively at the lift-off of 12.0 mm.

KW - Eddy current sensor

KW - lift-off measurement

KW - non-destructive testing

KW - sample-independence

KW - thickness measurement

U2 - 10.1109/TIM.2020.3038289

DO - 10.1109/TIM.2020.3038289

M3 - Article

AN - SCOPUS:85097163332

SN - 0018-9456

JO - IEEE Transactions on Instrumentation and Measurement

JF - IEEE Transactions on Instrumentation and Measurement

ER -

Inversion of lift-off distance and thickness for non-magnetic metal using eddy current testing

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Keywords

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Electromagnetic Sensing Group

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