Multi-Body Dynamics Simulation of Hoisting Wire Rope and Its Stress Analysis

提升钢丝绳多体动力学仿真及股丝应力分析

School of Mechanical Engineering, Northwestern Polytechnical University, Xi'an 710072, China

Received: 2 September 2019

Abstract

As a key component of the hoisting system of the crane, the steel wire rope will bear a variety of loading actions such as stretching, bending, vibration and impact in the process of traction hoisting. Therefore, it is important to determinate the dynamic characteristics of the steel wire rope under complex loads and understand the stress-strain state to predict the risk of hoisting operation in advance. This article takes the bridge crane as the engineering background, first, a dynamic model of a steel wire rope lifting system based on ADAMS/Cable was established, and the dynamic stress spectrum of the steel wire rope during the lifting process was calculated and obtained. Secondly, by establishing the geometric model and finite element model of the wire rope, the tensile stress and wire displacement distribution of the wire rope and the contact stress between the wire rope and the pulley and the wires inside the wire rope are analyzed during the lifting process of the crane. The final results show that the instantaneous acceleration of the steel wire rope increases the maximum tensile stress of the steel wire rope by 37% compared with the stable lifting stage at the instant of starting the steel wire rope, causes an increase in the stress amplitude of the wire rope cross section, and the lifting process of the steel wire rope is accompanied by unstable vibration loads. The analysis found that the outermost cross-section of the steel wire rope's outer strand was subjected to the greatest stress, and its local maximum tensile stress amplitude was increased by 56% compared to the stable lifting stage. The contact stress generated by the contact between the steel wire rope and the pulley causes contact wear on the external and internal strands of the steel wire rope, and promotes fatigue fracture of the steel wire rope.

摘要

钢丝绳作为起重机提升系统的关键部件，在牵引提升过程中将承受拉伸、弯曲、振动和冲击等多种载荷作用，因此研究复杂载荷下钢丝绳动力学特性，掌握钢丝绳的应力应变状态对提前管理起重机吊装作业风险有重要作用。以桥式起重机为工程背景，首先建立基于ADAMS/Cable的钢丝绳提升系统的动力学模型，计算获得了钢丝绳在提升过程中的动态应力谱。其次通过建立钢丝绳的几何模型和有限元模型，分析起重机在提升过程中钢丝绳的拉伸应力和钢丝位移分布及其钢丝绳与滑轮及钢丝绳内部各丝的接触应力。结果表明，钢丝绳启动瞬间，瞬时加速度使钢丝绳承受最大拉应力比稳定提升阶段增大37%，导致钢丝绳横截面应力幅值升高，钢丝绳在提升过程伴随不稳定的振动载荷。分析发现钢丝绳外股最外层钢丝横截面承受应力最大，其局部最大拉伸应力幅值比稳定提升阶段提高了56%。钢丝绳与滑轮接触产生的接触应力对钢丝绳外部及内部股丝产生接触磨损，促进钢丝绳发生磨损疲劳断裂。