Distinguish Abnormal Tensile and Torsional Stresses of Steel Wire Rope Using Magnetoelastic Effect

Nondestructive testing and structural health monitoring are highly important for safe operation of industrial systems. Steel wire ropes are key load-bearing components in these systems. Under the condition where multiple wire ropes are used simultaneously, the safe operation of the system will then be affected if the stress in these wire ropes is inconsistent. To date, research has focused mainly on changes in the tensile stress in steel wire ropes. Steel wire ropes are also affected by torsional stress during actual operation. The spiral structure of the wire rope means that when the torsional stress in the wire rope changes, then the tensile stress will also change. Abnormal tensile or torsional stresses in a wire rope will cause abnormal tensile stress in the wire rope. However, the treatment methods for these two stresses are different. It is thus necessary to distinguish the tensile and torsional stresses in steel wire ropes. This study uses the magnetoelastic effect to measure abnormal tensile and torsional stresses in steel wire rope through the time-domain and frequency-domain characteristics of a white noise signal. The method is to detect and distinguish the relative change of stresses in the multiple steel wire ropes. The frequency spectrum of the detection signal is used to detect abnormal stresses. The root mean square and center of gravity frequency of the detection signal is extracted to distinguish abnormal tensile and torsional stresses in multiple steel wire ropes and monitor its health.