NON-DESTRUCTIVE TESTING METHOD FOR THE WIRE ROPE WITH DIFFERENT SURFACE WEAR

Steel wire ropes, as key load-bearing components, suffer from significant wear and broken wire damage during their service period, which poses a serious threat to operational safety. Addressing the issues such as the single excitation method in traditional eddy current detection methods, the large noise interference from the phase wave, and the low accuracy of damage quantitative identification, this paper proposes a new non-destructive testing method that combines a dual-level excitation structure with signal processing. Firstly, a dual-level excitation structure composed of three asymmetric magnetic poles on the left, middle, and right sides was designed. By using differentiated permanent magnet grades (N35/N52/N52) and a 60 mm magnetic pole spacing, two independent intervals with significantly different excitation intensities (up to 7.7%) were formed within the steel wire rope, effectively reducing mutual interference. Subsequently, through finite element simulation analysis, the influence of magnetic pole parameters on the excitation effect was investigated, and a signal processing method based on offset superposition and sliding average filtering was proposed to effectively suppress periodic phase wave noise. Experimental results show that this method established a high-precision cubic polynomial quantitative model between the number of broken wires and the peak-to-peak value of the eddy current signal (coefficient of determination R² = 0.995), and compared with existing detection devices, the error rate of broken wire identification was significantly reduced from 51.3% to 13.3%. This research provides an effective technical means for the precise quantitative identification of wire rope wear and broken wire damage, especially composite damage.