基于蠕滑理论的钢轨临界平面疲劳参量仿真

Simulation of Fatigue Parameters of Rail Critical Plane Based on Wheel-rail Creep Theory

为考虑轮轨蠕滑对钢轨疲劳裂纹萌生的影响，通过车辆-轨道多体动力学模型和钢轨有限元模型，分析不同线路条件下的轮轨接触压力和切向力对钢轨轨头（包括轨距角）的应力-应变响应，定量研究钢轨滚动接触疲劳裂纹萌生疲劳参量 FP中的正应力-应变部分与剪应力-应变部分对裂纹萌生的影响，并比较导向轮和非导向轮对 FP的影响。仿真结果表明，考虑轮轨蠕滑的情况下，钢轨轨头绝大部分节点处于三向受压状态，疲劳参量 FP主要是由剪应力-应变部分作用产生，对裂纹萌生预测应采用剪切型裂纹公式；FPmax所在的临界平面在钢轨横断面的投影线与横向水平轴呈105°～140°夹角，在水平面的投影线与纵向水平轴呈20°～50°夹角；导向轮作用下的 FPmax要远远大于非导向轮作用下的 FPmax 。

To consider the influence of the wheel-rail creep on the initiation life of rail rolling contact fatigue （RCF） cracks ,the vehicle-track multi-body dynamics models and rail FEM models were built to analyze the stress-strain responses of rail heads and gauge corners in w heel-rail contact pressures and tangential forces under different track conditions. FP ,the fatigue parameter of rail rolling contact fatigue crack initiation ,was analyzed to quantify the influence of its normal and shear stress-strain portions on crack initiation. A detailed comparison of FP was taken between the leading and trailing wheels over the rail. The simulation results show as follow s ：Considering the w heel-rail creep ,the vast majority of nodes in rail heads are being under three-di-mensional compression ,and FP is generated by action of the shear stress-strain portion ;the shear crack formula should be chosen to predict the RCF life ;the projection line of the critical plane of the value of FPmax on the rail cross-section takes an orientation about 105°~140° with respect to the lateral direction of the rail ;the projec-tion line of the same plane on the level plane takes an orientation about 20°~50° with respect to the longitudinal direction of the rail ;FPmax caused by the leading w heel is much larger than that by the trailing w heel.