高速列车车轮踏面滚压强化有限元分析

为提高镟修后高速列车车轮踏面强度和使用寿命，进行了车轮踏面滚压强化过程的数值模拟，并对滚压强化的工艺参数进行了优化. 以CRH3高速列车车轮为研究对象，建立了滚压轮-车轮-钢轨三维滚动接触有限元模型；通过计算不同滚压轮尺寸、滚压力及滚压道次对车轮踏面残余应力和等效塑性应变场分布的影响来分析滚压强化机理；采用Borrow-Miller准则修正的Manson-Coffin公式计算了滚压后轮轨接触时车轮踏面的疲劳裂纹萌生寿命，进而对车轮踏面滚压强化工艺参数进行优化. 研究结果表明:随着滚压力的增加，车轮踏面的疲劳裂纹萌生寿命先增后减，且随着滚压道次的增加而下降，即滚压道次的增加反而会降低车轮踏面的疲劳裂纹萌生寿命；滚压道次的增加对残余应力的影响不大，滚压轮圆弧半径的增加会导致疲劳裂纹萌生寿命小幅度增大；综合考虑，以滚压道次为3次、滚压力为1 kN、滚压轮圆弧半径为6 mm时的滚压效果最佳，此时车轮踏面的疲劳裂纹萌生寿命可提升约58%. 

Finite Element Analysis of Rolling Strengthening Process for Wheel Tread of High-Speed Trains

To improve the wheel tread strength and service life of high-speed trains after reprofiling, the numerical simulation of rolling strengthening for the wheel tread was carried out, and the process parameters of rolling strengthening were optimized. Focusing on the wheel of the CRH3 high-speed train, a three-dimensional rolling contact finite element model was established which combines the roller, wheel, and rail. According to the influences of roller size, rolling pressure and rolling time on the distributions of residual stress and equivalent plastic strain fields of the wheel tread, the rolling strengthening mechanism were numerically investigated. The fatigue crack initiation life of the wheel tread after rolling strengthening in wheel-rail contact were estimated by the Manson-Coffin model modified by Borrow-Miller criterion, and the process parameters of rolling strengthening were optimized. The results show that, with the increase of rolling force, the fatigue crack initiation life of the wheel tread increases at first and then decreases, and it decreases with the increasing rolling time, which implies that the increasing rolling time reduces the fatigue crack initiation life of the wheel tread. Meanwhile, increasing the rolling time has little effect on the residual stress, and the increasing roller radius leads to a small increase of the fatigue crack initiation life. In summary, the optimal rolling strengthening parameters can be considered as the rolling times of 3 times, rolling force of 1 kN and roller radius of 6 mm, which can increase the fatigue crack initiation life of the wheel tread by about 58%.