Article Article
Characteristics of Eddy Current Attenuation in Double-Layer Metallic Plate and Measurement of Gap Thickness

Multilayer metallic plate is made by stacking homogeneous or heterogeneous metallic plates and connecting them with fasteners. The air-gap thickness between the adjacent layers affects the performance of the plate structure. The eddy current testing (ECT) technology has been used for the nondestructive testing of multilayer plate. However, the effect of air gap on the characteristics of eddy current (EC) attenuation in multilayer plate remains unclear and the study of the relation between the response of the EC probe and the gap thickness is very limited. The computation results of the paper show that the air gap in a double-layer plate reduces the amplitude of EC density in the bottom layer and decreases the rate of EC attenuation in the top layer. The mechanism is revealed. The effect of gap thickness on probe response is investigated. It is found that the presence of air gap makes the EC response either larger or smaller, depending on the working frequency. The reason is explained based on the characteristics of EC attenuation. Thereupon, the experiment of measuring gap thickness using the ECT is carried out.



1. H. Chan, B. Masserey, and P. Fromme. Smart Mater. Struct. 24 (2), 025037 (2015). DOI: 10.1088/0964-1726/24/2/025037.

2. D. Hopkins et al. B-scan technique for localization and characterization of fatigue cracks around fastener holes in multi-layered structures. 44th Annual Conference on Review of Progress in Quantitative Nondestructive Evaluation. Utah, America, 140003 (2017).

3. X. Teng, T. Wierzbicki, and M. Huang. Int. J. Impact Eng. 35 (8), 870–884 (2008). DOI: 10.1016/j.ijimpeng.2008.01.008.

4. R. Mohammad, M. M. Tohid, and O. Togay. Thin-Walled Structures. 144, 106332 (2019). DOI: 10.1016/j.tws.2019.106332.

5. Y. Yuan, W. Cheng, and X. Yang. Nondestruct. Test. 33(1): 31–36 (2011).

6. M. Pan et al. IEEE Trans. Instrum. Meas. 62(10), 2849–2856 (2013). DOI: 10.1109/TIM.2013.2239892.

7. G. M. Javier, G. G. Jaime, and V. S. Ernesto. Sensors. 11 (3), 2525–2565 (2011). DOI: 10.3390/s110302525.

8. X. Mao and Y. Lei. NDT & E Intl. 78, 10–19 (2016). DOI: 10.1016/j.ndteint.2015.11.001.

9. Y. Yu, D. Zhang, and C. Lai, Tian G, et al. IEEE Trans. Instrum. Meas. 66(7), 1874–1882 (2017). DOI: 10.1109/TIM.2017.2669843.

10. J. S. Kim, H. I. Sang, and G. S. Park. A study on the skin effect and eddy current distributions in conductive media. 20th IEEE International Conference on Electrical Machines and Systems, Sydney, Australia, 8056094 (2017).

11. Q. Zhang, Y. Li, Y. Liao, Zeng Z, Lin J, Dai Y, et al. Res. Nondestruct. Eval. 3: 177–189 (2021). DOI: 10.1080/09349847.2021.1930306.

12. C. V. Dodd and W. E. Deeds. (1975). ORNL-TM-4958.

13. M. S. Luloff et al. NDT & E Intl. 96, 1–8 (2018). DOI: 10.1016/j.ndteint.2018.02.003.

14. S. K. Burke. J. Appl. Phys. 67 (1), 465–476 (1990). DOI: 10.1063/1.345227.

15. Y. Li, T. Theodoulidis, and G. Tian. IEEE Trans. Magn. 43 (11), 4010–4015 (2007). DOI: 10.1109/TMAG.2007.904930.

16. J. R. Bowler and D. J. Harrison. Measurement and calculation of transient eddy-currents in layered structure. 18th Annual Conference on Review of Progress in Quantitative Nondestructive Evaluation, Brunswick, Germany, 241–248 (1991).

17. Z. Mottl. NDT & E Intl. 23 (1), 11–18 (1990). DOI: 10.1016/0308-9126(90)91444-X.

18. G. Mook, O. Hesse, and V. Uchanin. Mater. Test. 49 (5), 258–264 (2007). DOI: 10.3139/120.100810.

19. S. Jiao, X. Liu, and Z. Zeng. IEEE Trans. Magn. 53 (7), 6201608 (2017). DOI: 10.1109/TMAG.2017.2669181.

20. H. Hoshikawa and K. Koyama. Mater Eval. 57(6): 587–593 (1999).

21. Z. Zeng et al. Chin. J. Mech. Eng. 32(1), 106–114 (2019). DOI: 10.1186/s10033-019-0419-6.

22. J. Zheng et al. Meas.Technol. 3: 30–32 (2003).

23. Z. Chen et al. Numerical Simulation Method of Electromagnetic Nondestructive Testing. (China Mechanical Industry Press, Beijing, 2017).

24. B. Bandelier et al. IEEE Trans. Magn. 35 (3), 1171–1174 (1999). DOI: 10.1109/20.767157.

25. I. Cerny, J. Sis, and D. Mikulova. Surf. Coat. Technol. 243, 20–27 (2014). DOI: 10.1016/j.surfcoat.2012.06.008.

26. S. Hosseini and A. Lakis. NDT & E Intl. 47, 70–79 (2012). DOI: 10.1016/j.ndteint.2011.12.001.

27. H. Shang, H. Zhang, and Q. Chen. Nondestruct. Test. 41(3): 9–13 (2019).

28. M. Le et al. Appl. Sciences-Basel. 12 (10), 12105175 (2022). DOI: 10.3390/app12105175.


Usage Shares
Total Views
63 Page Views
Total Shares
0 Tweets
0 PDF Downloads
0 Facebook Shares
Total Usage