Characteristics of Eddy Current Attenuation and Thickness Measurement of Metallic Plate

Autor: Zhiwei Zeng, Pengcheng Ding, Jiayi Li, Shaoni Jiao, Junming Lin, Yonghong Dai
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Chinese Journal of Mechanical Engineering, Vol 32, Iss 1, Pp 1-9 (2019)
Druh dokumentu: article
ISSN: 1000-9345
2192-8258
DOI: 10.1186/s10033-019-0419-6
Popis: Abstract In eddy current testing, the law of attenuation of eddy current (EC) is of great concern. In conductive half space under the excitation of uniform magnetic field, the EC density decreases exponentially in the depth direction. However, in conductor with finite thickness tested by coil, the distribution of EC in the depth direction is more complicated. This paper studies the characteristics of EC attenuation in metallic plate of finite thickness. Simulation results show that there is an EC reflection at the bottom of plate, which changes the law of EC attenuation. A new concept, namely the equivalent attenuation coefficient, is proposed to quantify the speed of EC attenuation. The characteristics of EC attenuation are utilized to explain the nonmonotonic relation between coil voltage and plate thickness. Procedure of selecting frequency is discussed. Thereafter, measurement of plate thickness is carried out and accurate result is obtained.
Databáze: Directory of Open Access Journals
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