Estimation of breakage position in wire rope cross-section by geometrical formulation of wire shape

Abstract

A wire rope is one of the main components of cranes and elevators. The wires of the rope gradually break with long-term use, and the rope eventually leads to fracture. Rope fracture might cause a serious accident, so it is important to clarify the mechanism of rope damage in order to prevent such accidents. In recent years, IWRC ropes, which have become a mainstream crane rope, are found to have wire breakage inside the rope. Therefore, it is difficult to properly identify the damage of a rope by visual observation, and a method to obtain the wire breakage state in the rope cross section including the inner wires is required. This study proposes a method for estimating the position of wires in the rope cross-section based on geometrical formulation. A damaged rope including wire breakage was produced by S-bending fatigue test, and the locations of wire breakages were estimated by this method. As a result of evaluating the positional relationship between the wire breakage position and the S-bending fatigue test sheave, it was clarified that the relationship between the area prone to wire breakage and the wire position relative to the rope or the test sheave was different for each type of wire. Furthermore, by comparing the wire breakage positions obtained from the cross-sectional images taken by X-ray CT, it was confirmed that the developed method can predict the wire breakage positions with sufficient accuracy to evaluate the damage status of ropes. This study makes it possible to evaluate the relationship between the fatigue test conditions and each wire in the rope cross-section, which is expected to further analyze the damage mechanism of wire ropes.

Keywords

• wire rope
• iwrc
• s-bending fatigue test
• vector analysis
• wire breakage