轮轨高速滚动接触及钢轨疲劳裂纹扩展研究

为研究高速列车轮轨滚动接触疲劳损伤,通过引入应变率效应,获得了轮轨接触作用力的分布,并基于最大周向应力判据,对车轮滚过裂纹过程中裂纹可能的扩展角度进行了统计分析,确定了钢轨表面疲劳裂纹的扩展方向.根据威布尔分布,用可能扩展角度均值作为裂纹扩展方向,获得了裂纹扩展路径.研究结果表明,低速列车钢轨的裂纹扩展为张开型裂纹逐渐变为滑开型裂纹,高速列车的钢轨裂纹扩展基本都是张开型裂纹;高速列车钢轨的裂纹扩展速率快于低速列车钢轨;模拟的裂纹路径与实验测得的裂纹路径吻合,验证了用可能扩展角度的均值作为裂纹扩展方向的合理性. 

Research on Wheel/Rail Rolling Contact at High Speed and Fatigue Crack Propagation in Rail

To analyze the rolling contact fatigue damage of wheel/rail for high-speed trains, the distribution of contact forces between wheel and rail was obtained by introducing the strain-rate effect. Based on the maximum circumferential stress, the possible propagation angle of the crack was counted when a wheel roll over a crack and the crack propagation directions were determined. According to the Weibull distribution, crack path was obtained by using the average crack propagation angle as the crack propagation direction. The results show that the crack mode becomes to sliding crack from opening crack for low-speed trains. The crack mode is always opening crack for high-speed trains. The crack propagation velocity for high-speed trains is faster than that of low-speed trains. The simulation crack path is in agreement with the experimental crack path, which proves that it is reasonable to use the average crack propagation as crack propagation direction.