Affiliations: School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei, 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, Wuhan 430074, Hubei, China. E-mail:yihuakang@mail.hust.edu.cn
Abstract: In order to improve the signal-to-noise ratio (SNR) of
the rough surface crack signal, a magnetic flux leakage (MFL) detection
technique based on the magnetic medium lift-off is proposed for the first
time. The influence of surface roughness on the crack signal is analyzed
based on a simplified model of the workpiece with rough surface. By
replacing the air region of the lift-off between the sensor and workpiece
with magnetic medium, the leakage magnetic field of the crack and surface
roughness are redistributed which results in the change of signals acquired
by the sensor. The improvement of the SNR comparing to the widely used air
medium lift-off is demonstrated and confirmed through simulation approaches.
In addition, the different thickness and relative permeability of the
magnetic medium lift-off are analyzed to optimize the improvement method in
this paper.
Keywords: Magnetic flux leakage (MFL) detection, surface roughness, signal-to-noise ratio (SNR), lift-off
