Research On Failure Behavior And Damage Mechanism Of Wire Ropes In Parallel Grooved Multi-layer Winding

The damage and the failure of wire rope is directly related to safety, reliability and technology economy of the use of wire rope which has been a focus of study attracts much attention these days. With the increasing of the units of the lifting load, the parallel grooved multi-layer winding is more and more widely used in the drive system of the lifting machinery. The problems such as the failure behaviors of the wire rope, damage mechanism and regulations that each condition influences the wire rope working life in the parallel grooved multi-layer winding, haven't a clear research conclusion and the basis of the test and argument. So in this paper, it combines theoretical analysis with experimental research to research the failure behavior and damage mechanism of the wire rope of the parallel grooved multi-layer winding in order to master the regulation of the failure behavior of the parallel grooved multi-layer winding and explore the damage mechanism of the wire rope.The complexity of the wire rope structure determines that its damage and failure behaviors are closely related to the service conditions. Based on the study of wire rope parallel grooved multilayer winding characteristics, the wire rope on the drum are arranged into three forms,"Pyramid" form, axes intersection "X" shape and" wedge" from, and the contact mechanics behaviors of wire ropes under the three arrangement forms are analyzed in this paper. On this basis, focusing on theoretical analysis of the wear of wire rope during parallel grooved multilayer winding and bending fatigue damage by combining qualitative method with quantitative method. The results show that the force of wire rope winding process and the degree of wear in the rope are closely related to winding positions of wire ropes on wound roll and the arrangement form; bending diameter D during reverse bend of wire rope is the main influencing factor that determines the degree of fatigue damage.The complexity of damage and failure of wire rope makes the research method based on combination of theories analysis and experimental study. Therefore, the paper research and develop the wear test device of multilayer winding wire rope and sheave that can simulate the real operation condition of parallel grooved multi-layer winding, based on comparison and summary on advantages and disadvantages of wire rope test device, according to the operating Features of steel wire rope for hoisting machinery. Besides, the two factors:performance of lubricant grease, diameter of sheaves are chose to be the objects of investigation by using the test device, comparison experiments on two groups of parallel grooved multi-layer winding wire rope and sheave failure is executed.The regularity of failure of wire rope is the important basis for the proper selection and arrangement of service conditions. Failure form of multilayer winding wire rope, distribution and development discipline of broken wire, variation characteristics of wear in wire rope, the influence of performance of lubricant grease, diameter of sheaves on the life of wire rope and so on are researched profoundly by analyzing and comparing test results of the two groups of failure of wire rope on the different performance of lubricant grease and diameter of sheaves. The results indicate that the failure form of parallel grooved multi-layer winding wire rope is outer layer wire breaking; distribution of broken wire and variation of wear in wire rope correlate closely to the position where the wire rope lie in the drum; the performance of lubricant grease has no discernible effect on the life, but the diameter ratio of sheave and wire rope has significant effect on the life of wire rope.Failure process of parallel grooved multi-layer winding wire rope is essentially the process of the emergence and development of the broken wire in wire rope. Broken wire position of parallel grooved multi-layer winding wire rope and fracture surface of broken wire are analyzed in this paper, fracture behaviors and fracture mechanisms of outer layer wire and rope core are discussed. The results revealed that fracture of outer layer wire is the result of a combination of plastic deformation caused by the extrusion of wires and wear caused by the extrusion of wire ropes during the parallel grooved multi-layer winding, and the fractured of wire in rope core is caused by fatigue failure under the influence of fretting wear.