Chin. Phys. B, 2018, Vol. 27(3): 030301    DOI: 10.1088/1674-1056/27/3/030301
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# Analytical model of tilted driver-pickup coils for eddy current nondestructive evaluation

Bing-Hua Cao(曹丙花)1,2, Chao Li(李超)1, Meng-Bao Fan(范孟豹)2,3, Bo Ye(叶波)4, Gui-Yun Tian(田贵云)5
1 School of Information and Control Engineering, China University of Mining and Technology, Xuzhou 221116, China;
2 Jiangsu Key Laboratory of Mine Mechanical and Electrical Equipment, China University of Mining and Technology, Xuzhou 221116, China;
3 School of Mechatronic Engineering, China University of Mining and Technology, Xuzhou 221116, China;
4 Faculty of Information Engineering and Automation, Kunming University of Science and Technology, Kunming 650500, China;
5 School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
Abstract  A driver-pickup probe possesses better sensitivity and flexibility due to individual optimization of a coil. It is frequently observed in an eddy current (EC) array probe. In this work, a tilted non-coaxial driver-pickup probe above a multilayered conducting plate is analytically modeled with spatial transformation for eddy current nondestructive evaluation. Basically, the core of the formulation is to obtain the projection of magnetic vector potential (MVP) from the driver coil onto the vector along the tilted pickup coil, which is divided into two key steps. The first step is to make a projection of MVP along the pickup coil onto a horizontal plane, and the second one is to build the relationship between the projected MVP and the MVP along the driver coil. Afterwards, an analytical model for the case of a layered plate is established with the reflection and transmission theory of electromagnetic fields. The calculated values from the resulting model indicate good agreement with those from the finite element model (FEM) and experiments, which validates the developed analytical model.
Received:  08 August 2017      Published:  05 March 2018
 PACS: 03.50.-z (Classical field theories) 03.50.De (Classical electromagnetism, Maxwell equations) 41.20.-q (Applied classical electromagnetism) 41.20.Gz (Magnetostatics; magnetic shielding, magnetic induction, boundary-value problems)
Fund: Project supported by the National Natural Science Foundation of China (Grant Nos. 61701500, 51677187, and 51465024).
Corresponding Authors:  Chao Li     E-mail:  finchlee@cumt.edu.cn