The metal thickness detection using pulsed eddy-current computation and detection method
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Through detecting method of pulsed eddy-current (PEC) and according to thickness testing model of multi-layer metal, infer the mathematical model of eddy current testing method in single-layer metal. Use Maxwell field equations to find solutions of vector magnetic potential in its boundary conditions thus infer the impedance of hollow coil placed right above metal. Analyze the variation relationship between induced current and metal thickness in theory level. (1) Obtain three characteristic signals of induced current: altitude of current peak value (ACPV), time of reaching current peak (TRCP) and time of traversing zero point (TTZP). The thickness of the metal and the distance between the metal and coil were obtained. (2) Introduce the concept of the lift-off intersection point (LOI) and puts forward a new method of metal thickness detection based on the LOI. By analyzing the results of the experiment, it confirms the feasibility of the LOI of measurement in the metal thickness.
KeywordsMetal thickness Pulsed eddy-current (PEC) Nondestructive test Lift-off intersection point (LOI)
This work was financially supported by National Nature Science Foundation of China (Grant Nos. 51478383, 5120916, 51678470), National Program on Key Research SUB-Project (Grant No. 2017YFC0704207-03), Youth Science and Technology Project of Shaanxi Province (Grant No. 2016KJXX-64), Science and technology project of Xi’an (Grant No. JKDZ0011), Science and technology project of Xi’an BEI LIN (Grant No. GX1705).
- 4.Zheng, G., Xia, R., Chen, Y., et al.: Research on double coil pulse eddy current thickness measurement. In: Proceedings of the International Conference on Intelligent Computation Technology and Automation. pp. 406–409 (2017)Google Scholar
- 5.Azaman, K.N., Sophian, A., Nafiah, F.: Effects of coil diameter in thickness measurement using pulsed eddy current non-destructive testing. Mater. Sci. Eng. 260(1), 012001 (2017)Google Scholar
- 13.Yuedong, W.U., Huang, C., Xiong, B., et al.: Compensation method of sensor lift-off effect to thickness measurement of pulsed eddy current. Ship Electr. Eng., 2015Google Scholar
- 15.Huang, C., Wu, X.: Probe lift-off compensation method for pulsed eddy current thickness measurement. In: Proceedings of the International Conference on IEEE Antennas and Propagation. pp. 937–939 (2014)Google Scholar
- 16.Gang, Z., Ding, L., Zhen, Z., et al.: Research on thickness measurement based on lift-off intersection of pulsed eddy current. Chin. J. Sci. Instr. 29(8), 1745–1749 (2008)Google Scholar
- 17.Lefebvre, J.H.V.: Mandache C. Pulsed eddy current measurement of lift-off. In: Proceedings of the Review of Progress in Quantitative Nondestructive Evaluation. American Institute of Physics, pp. 669–676 (2006)Google Scholar
- 19.Cheng, C.C., Dodd, C.V., Deeds, W.E.: General analysis of probe coils near stratified conductors. Int. J. Nondestr. Test. 3, 109–130 (1971)Google Scholar
- 21.Chen, X.: Time-domain analytic expressions for pulsed eddy current field of conductive plate and characteristic quantity for thickness measurement. Trans. China Electr. Soc. 28(7), 1–8 (2013)Google Scholar