Crack Detection Method Based on the Poly-Magnetic Probe Structure

Abstract

The detection of cracks has been a difficult task in the damage detection of ferromagnetic components. If the defects cannot be found and treated in time, the damage degree of the defects will gradually increase and there will be heavy losses. The signal amplitude of the cracks is low and the signal is complex, so the cracks are difficult to identify. Aiming to solve this problem, this article explores the influence law of the probe magnetic conductor structure and sensor position on the detection results and proposes a method of detecting the cracks based on the poly-magnetic probe. An arc-shaped magnetic conductor structure is proposed to increase the magnetic flux density of the poly-magnetic probe. The effect of the position of the sensor on the defect detection is then studied, and a method of optimizing the poly-magnetic probe is proposed to improve the amplitude of the crack signal. Cracks with widths of 0.2, 0.5, 1.0, 1.5, and 2.0 mm are experimented, respectively. It was shown in experiments that the crack with a width of 0.2 mm can be detected, and the peak-to-peak amplitude of the defect detection signal of the optimized poly-magnetic probe method is 180%–472% higher.