Research On Inherent Properties And Mechanical Performances Of Wire Rope

Wire rope is a flexible space helix steel product, which has the characteristics of flexible, damping absorption and high strength. It is essential to have safety performance for rope.And therefore, wire rope is widely used in buildings, bridges, machinery processing, mining production, communications, transportation, aerospace and other fields. Due to the complicated structure and bearing more complex forces, wire rope have to endure stretching, bending, torsion, contact stress and other dynamic loads. It is composed by many steel wires, whose material is non-alloy carbon steel with high-strength. Rope is eventually fabricated by steel wires after a series of process, such as wire rod, heat treatment, pickling wiredrawing and stranding. Thus, the mechanical properties of the steel have a direct effect on the mechanical performance of the entire rope. It is difficult to measure stress state of rope, stress magnitude and distribution in the wires of different wire layers and is important for rope of strength, longevity and safety assessment. To ensure its safe and efficient operation within the specified time limit, it is very necessary to research on inherent properties and mechanical performances of wire rope. Meanwhile, the selection, structure design, use and maintenance is very important. In this paper, the mathematical models of a helix of the wire in straight and bend state were established by analyzing the structural characteristics of wire rope and space spiral winding relations of wire. On this basis, the Frenet-Serret frame diagram of space curve was established by using the theory of different geometry. Space vector expressions of double helix of the wire in straight and bend state were deduced, respectively. By using the calculation methods of curvature and torsion of space curve and programming procedures of MATLAB, the magnitude and distribution of curvature and torsion in the wires of different wire layers of spiral rope1×37IWS and multi-strand rope6x36WS+IWRC in straight and bend state were calculated and analyzed. Based on the theory of elasticity Costello’s rope, the characteristics of stress and deformation of the wire after loading were analyzed. The expressions of tensile stress and additional stresses that generated by stretching of the wire in strand and stranded ropes were deduced. The magnitude and distribution of tensile stress and additional stresses in the wires of different wire layers of spiral rope1×37IWS and stranded ropes6×36WS+IWRC in straight and bend state. By theoretical analyzing the changes characteristic of curvature when turn straight into the bend state, the magnitude and distribution of bending stress in the wires of different wire layers of spiral rope1×37IWS and stranded ropes6×36WS+IWRC in rope groove were calculated and analyzed.Based on three-dimensional modeling software Pro/E and analysis software ANSYS Workbench, the solid models and finite element analysis models of ropes were established respectively. By using Augmented-Lagrangian algorithm, the contact models and contact parameters in the wires of different wire layers, and between rope and pulley or frictional wheel were added and set. Combined with the appropriate boundary conditions for loading analysis, the distribution of stress and deformation in the wires of different wire layers of spiral rope1×37IWS and stranded ropes6×36WS+IWRC were simulated in straight state. The distribution of stress and deformation in the wires of different wire layers of spiral rope6×7IWS were simulated in bend state. Finally, By testing about separating strand in wire rope of6×7IWR+FC and6×36WS+FC, breaking force, bending times and torsional times were obtained, the effects of twisting ways on mechanical properties of steel were analyzed by using mathematical statistical methods.