Failure Evolutions of the Vibration-Worn Wire Ropes Under Different Service States in Mine

Abstract

The service environment of the multilayer winding wire rope in mine hoist is complex and harsh, and the working conditions such as poor lubrication and mineral dust pollution are inevitable. The harsh environment is easy to accelerate the friction damage of a winding contact wire rope, coupled with the vibration effect, and eventually causing the rapid degradation of its mechanical properties. The mapping relationships between the vibration condition, lubricating state as well as mineral dust environment and the performance degradation characteristics of the vibration-worn wire ropes were explored based on experimentation in the article, and the fracture failure mechanisms under different stress states were revealed. The conclusions show that the wire rope mainly undergoes the stages of structural deformation, elastic deformation, plastic deformation, localized necking plastic deformation and fracture at the action of tensile load, the necking appears in the stage of localized necking plastic deformation, and the fracture of steel wire is cup-cone shape. Additionally, the bending fatigue fracture of steel wire is a process of cumulative regression. The evolution of the hazardous region of bending fatigue broken wires for the vibration-worn wire rope in the state of dry friction is concentrated in the wear region first, and then dispersed in the strand-strand bending extrusion contact region and the region subjected to relatively large tensile-bending coupling stress. The breaking force reduces by 6.03% and the number of bends when the wire rope reaches the scrap standard reduces by 11.29% with the lubricating state of wire rope deteriorates from full lubrication to dry friction. The mineral dust has little influence on the service performance of wire rope in the state of full lubrication. Furthermore, micropore aggregation fracture occurs for the steel wire at the action of tensile load, while the bending fatigue fracture mechanism of steel wire is mainly brittle fracture, the fatigue source zone is transferred to the wear surface or subsurface, and the speed of crack propagation is accelerated for the worn steel wire.

Keywords: wire rope, vibration wear, tensile strength, bending fatigue, fracture failure mechanism