钢轨轨缝接触-冲击的有限元分析

Finite Element Analysis of Contact-Impact of Wheel/Rail at Rail Gap

基于弹性点支承梁模型,采用三维非线性动力分析有限元程序ANSYS/LS-DYNA3D,建立了轮轨轨缝处接触-冲击有限元分析模型,通过模拟车轮经过轨缝时冲击钢轨接头的过程,研究了冲击过程中轨头的应力分布情况.结果表明:车轮冲击钢轨接头时,轮轨间最大垂向接触力出现在冲击开始后0.5ms左右,约为静载时的2.6倍,且在一定时间段里,轮轨间出现瞬时脱离现象.同时,轮轨间接触力及各种最大应力均随着轴重的增加成正比增大;当车轮冲击轨端瞬时,最大VonMises等效应力出现在轨端头部,约为静接触时的3倍;最大剪应力发生在离轨顶面5mm处.研究结果对于揭示轨头的冲击破坏机理和改善铁路轨缝连接方式具有指导作用.

Based on the discrete elastic support model, a finite element analysis model for the contact-impact problem due to the gap of rail joint was proposed by making the use of three-dimensional nonlinear finite element dynamic analysis code ANSYS/LS-DYNA3D. The model was used to simulate the impact process of a running wheel to the rail joint. The stress distributions within the rail-head at the rail gap are studied in detail as well. It was found that the maximum vertical contact force appeared after the impact initiating of 0.5 ms, which was about 2.6 times as much as the static contact force. The wheel/rail remained separated for a period of time after the occurrence of the wheel/rail impact. The maximum contact force of the wheel/rail and the maximum stress increased linearly with the increase of the axle load. The maximum Von Mises equivalent stress reached the peak value at the head of rail-end, which was about 3 times as much as that in a static contact. The peak shear stress appeared at a depth of 5 mm from the rail top surface. The results could be used as the reference to further understand the mechanism of the impacting damage at the rail-head and to improve the rail joint mode.