Wire breakage evaluation of IWRC 6×Fi(29) considering position in wire rope cross section

Abstract

SWire rope is one of the main components in mechanical structures such as cranes and elevators. During hoisting and lowering of a load, the rope moves along the sheaves under tension and is subjected to bending loads. This repetitive bending load causes the wires to gradually break, leading to rope rupture. Furthermore, IWRC ropes which have become the mainstream rope for cranes in recent years had clarified that wire breakage occur preferentially inside the rope. Therefore, it is necessary to establish a method for detecting wire breakage inside the rope and to elucidate the breakage mechanism. However, since ropes are composed of multiple twisted wires, it is difficult to identify the position of wire breakages in the rope cross-section. In this study, the positions of wire breakages in rope cross-section were evaluated applying a recently proposed estimation method. The subject ropes were prepared by S-bending fatigue test. The results of wire breakage distribution in a rope cross-section revealed that there were conditions under which wires were prone to breakage, depending on the sheave contact area and the positional relationship with adjacent wires. In addition, the mechanism of visible wire breakage and its relationship with the current disposal standards were discussed.