The bending fatigue of the wire rope is caused by running on the sky wheel or opening and closing on the single-layer drum.
Fatigue cracks generally start at the contact point between the external steel wire and the surface of the crown wheel or drum or at the intersection between the various steels. Then the cracks continue to increase with the number of bendings, and finally fractures perpendicular to the axial direction of the steel wire appear. Fatigue breakage occurs more frequently on the inner side of the wire rope bend (at the point of contact with the crown wheel) than on the outer side of the bend (at the point of highest bending stress). The fatigue resistance of a wire rope generally increases with the increase in the number of outer wires of the rope and the decrease in diameter. However, this improvement is accompanied by a decrease in the abrasion resistance of the rope.
The durability of the wire rope can also be increased by increasing the crown wheel or increasing the diameter of the drum or by reducing the rope tension. Wear or corrosion may increase the rate of crack formation and crack propagation. However, good steel rope lubrication and relubrication during use will reduce the friction between the steel rope components and then improve the fatigue resistance of the steel rope.