重载轮轨黏着特性的数值分析

基于ALE (Arbitrary Lagrangian Eulerian)有限元建立稳态轮轨滚动接触的三维有限元模型.利用该模型计算和分析重载轮轨滚动接触的黏着特性,并研究不同速度等级对重载轮轨黏着蠕滑特性的影响.用该模型对重载大功率机车车轮在轨道上从制动、惰行到牵引过程进行计算,得到了这一过程中轮轨接触状态的变化规律和黏着特性曲线.在重载大功率机车从制动、惰行到牵引的过程中,轮轨纵向摩擦力由反方向饱和状态逐渐转变成牵引方向饱和状态,而轮轨横向摩擦力始终呈反对称性分布,其最大值位置先是逐渐靠近接触斑中心,然后又逐渐远离之；摩擦力矢量呈旋转分布,其方向从与运动方向相反逐渐变为与运动方向相同,其旋转中心从轮缘附近逐渐进入接触斑,随后又逐渐向轮缘一侧移动；当轮轨纵向蠕滑率较小(≤0.003)时,黏着力随纵向蠕滑率的增加而近似线性增加,但运行速度对此影响不大；进入大蠕滑率(＞0.003)区域后,黏着力随蠕滑率的增加而减小,并且速度越高,黏着力降低得越快.

Numerical Analysis of Wheel/Rail Adhesion Characteristics for Heavy Haul Train

A wheel/rail steady state rolling contact finite element model based on ALE(Arbitrary Lagrangian Eulerian) finite element method is developed.The model is applied to calculate and analyze the wheel/rail adhesion characteristics of heavy haul train,and also to study the influence of different running speed on the wheel/rail adhesion and creep characteristics.The model is used to analyze the process from braking,idle running to traction of wheels on track for heavy haul high power locomotive.The change law of wheel/rail contact state and the adhesion characteristic curve during this process are obtained.During braking,idle running and traction process of heavy haul high power locomotive,the longitudinal wheel/rail friction force changes gradually from opposite direction saturation state to traction direction saturation state.Whereas the lateral wheel/rail friction force always distributes anti-symmetrically and the location of its maximum value moves towards the center of the contact patch then gradually moves away from the center.During this process,the vector distribution of friction force changes gradually from the opposite motion direction to the same motion direction,and the friction force vector shows rotating distribution with the rotating center moves from wheel flange to the contact patch and then gradually to the side of wheel flange.Under low longitudinal wheel/rail creep rate situation(≤0.003),the adhesive force increases linearly with the increase of longitudinal creep rate while the running speed has no obvious impact.Under high creep rate situation(>0.003),the adhesive force descends with the increase of creep rate,and higher speed will lead to faster descending of adhesive force.