小半径曲线上P75钢轨打磨廓形设计及应用研究

Research on Design and Applications of Grinding Profiles of P75 Rail on Sharp Curve

以国内某重载铁路R400 m曲线P75钢轨为研究对象,建立了轮轨接触模型和轮径差曲线描述模型,选取代表性车轮踏面和钢轨廓形,采用轮径差曲线逆向求解法优化了轮轨接触区域钢轨廓形,并依据打磨量最小化原则设计得到了曲线钢轨打磨廓形。建立了实测参数下的车辆-轨道多体动力学仿真模型,对比分析了实测廓形和设计廓形匹配下的动力学指标。按钢轨廓形设计要求,在该R400 m曲线上实施了钢轨打磨试验和轮轨动力学测试。研究结果表明,优化后轮径差曲线趋于平滑,车辆曲线通过能力得到提高,抗脱轨能力得到保持;轮轨关系得到显著改善、轮轨接触点交叉跳跃和集中问题得到缓解;轮轨横向力减小20%以上,脱轨系数减小16%以上,钢轨法向接触应力减小32%以上,轮轨蠕滑力减小26%以上;实施打磨后,轮轨横向力减小34%以上,脱轨系数减小35%以上,钢轨振动加速度减小35%以上;打磨后3个月轨面疲劳伤损未见明显发展,钢轨使用寿命由前一换轨周期的8个月延长至13.5个月。仿真分析和打磨试验验证了钢轨廓形设计方法在重载铁路小半径曲线的应用效果。

Taking the P75 rail on R 400 m curve of a heavy-haul railway as the research object,the description model of wheel-rail contacts and wheel diameter difference curve was established,and the representative measured wheel treads and rail profiles were selected.The rail profiles in the wheel-rail contact areas were optimized by the reverse solution method of the wheel diameter difference curves,and the grinding profile of the curves was designed according to the principle of minimizing the amounts of grinding.A simulation model of vehicle-track multi-body dynamics with real parameters was established in the multi-body dynamics software,and the dynamic indexes matching with measured and designed profiles were compared and analyzed.The R 400 m curve was ground with designed profiles,and the wheel-rail dynamics tests were carried out.The results show that,after optimization,the curves of wheel diameter difference tend to be smoother,the curve passing ability of vehicle is improveds,and the anti-derailment ability is maintained.The wheel-rail relationship is significantly improved matching with the designed profiles,and the cross-jumping and concentration problems at the wheel-rail contact points are alleviated.The lateral wheel-rail force was reduced by more than 20%,the derailment coefficient was reduced by more than 16%,the normal contact stress of the rail is reduced by more than 32%,and the wheel-rail creep force was reduced by more than 26%.After grinding with the designed profile,the lateral wheel-rail force is reduced by more than 34%,the derailment coefficient is reduced by more than 34%,the vibration acceleration of the rail is reduced by more than 35%,the fatigue damage of the rail surface doesn t develop significantly in 3 months,and the service life of the rail is extended from 8 months to 13 months.The application effectiveness of rail profile design method on sharp curve in heavy-haul railway is verified through simulation analysis and field tests.