The effect of variable tensile stress on the MFL signal response of defective wire ropes

This paper considers the effect of tensile stress on the strength of the magnetic leakage field of a steel wire rope defect, which is easily neglected in the actual detection process. An inspection platform was built to load a variable force onto reproduced samples of typical defective wire ropes. Coil sensors were used to detect the radial component of the magnetic leakage field. In addition, the wavelet denoising method and wavelet singularity analysis were used to reduce the background noise and acquire the peak-to-peak values of low-frequency components of the magnetic flux leakage (MFL) signal, respectively. The validity of the extracted data and the effect of tensile stress on the strength of the magnetic leakage field were verified via the analysis of variance method. The experimental results reveal that the peak-to-peak values of the MFL signal from all the defective wire ropes increase with increasing tensile stress, in an approximately linear relationship. The tensile stress must remain consistent and stable during inspection to obtain better repeatability. Moreover, the detection accuracy can be improved by increasing the loading force within an appropriate range. The results of this study have significant implications for the enhancement of the reliability of wire rope defect detection.