Affiliations: [a] School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, China
Correspondence:
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Corresponding author: Yihua Kang, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, 430074, Wuhan, China. E-mail: [email protected]
Abstract: In order to illustrate influence of surface roughness on the energy change of excitation process in thickness measurement of electromagnetic acoustic transducer (EMAT), the change of Lorentz force during the excitation process is analyzed theoretically. A finite element simulation model of EMAT is established with different surface roughness. The distribution of eddy current density and Lorentz force density of different rough surface is discussed. The results show that the eddy current density gets nonuniform due to the irregular profile of the surface. The average value of Lorentz force density decreases with the increase of surface roughness Ra, which makes the excitation energy of EMAT get weaker. Finally, the experiment results verify the analysis of the theory and finite element simulation.
Keywords: Surface roughness, eddy current density, Lorentz force density, excitation energy change, EMAT
