重载铁路固定辙叉区轮轨瞬态滚动接触行为分析

固定辙叉有害空间造成的轨线不连续及结构不平顺大幅加剧车辆与辙叉间的动态相互作用,进而引起道岔伤损劣化加剧及服役寿命缩短。以重载铁路12号固定辙叉为研究对象,基于显式积分算法,建立考虑材料弹塑性及轮轨真实几何廓形的车轮-辙叉三维轮轨瞬态滚动接触有限元模型,研究不同运营速度下车轮不同方向通过时车轮与固定辙叉动态相互作用及轮轨接触行为,详细分析轮载过渡区内辙叉钢轨应力、应变大小及分布规律,结合材料安定图及疲劳指数对轮轨接触疲劳伤损特性进行分析,得到了钢轨滚动接触疲劳伤损易发区域为心轨断面顶宽20~30 mm,与现场固定辙叉疲劳裂纹发生位置基本一致。所建立的模型及研究结论能够为固定辙叉结构优化及疲劳寿命预测提供理论支撑。

Analysis of 3D Transient Wheel-rail Rolling Contact Behavior for Fixed Frog in Heavy Haul Railways

The track discontinuity and structural irregularity caused by the gap in the frog and structure will increase the dynamic interaction between the train and the frog,which is the key factor leading to the aggravation of the turnout damage and the shortening of service life.A 3D wheel-frog transient rolling contact finite element model of No.12 fixed frog in heavy haul railway was established based on the explicit time integration scheme,considering the material elastoplasticity and the true geometry of the wheel and rail.An analysis was made on the dynamic interaction between the wheel and the fixed frog and the contact behavior between the wheel and the rail when wheels pass in different directions at different operating speeds.The distribution and the magnitude of the stress/strain of frog rails in the wheel-load transition zone were analyzed.The characteristics of rolling contact fatigue damage were analyzed based on the shakedown map and the fatigue index.The nose rail section of 20-30 mm in width was the area where the rolling contact fatigue may occur,which was basically consistent with the location of fixed frog fatigue crack.The model and results can be a new tool for the prediction of rolling contact fatigue and structure optimization of frog.