小半径曲线钢轨非对称打磨廓形设计方法

为设计可提升列车小半径曲线通过性能的钢轨非对称打磨目标廓形，对中国现有CN60钢轨廓形进行了几何推导；以钢轨廓形几何参数作为设计变量，以车辆系统多体动力学指标作为综合目标函数，考虑钢轨打磨约束条件，提出了一种针对小半径曲线钢轨非对称打磨廓形的多目标数值优化模型；基于差分进化算法编写了相应的数值计算程序，并选择合理的计算参数求解了优化模型；根据实际线路参数分析了优化后钢轨打磨廓形的轮轨接触几何特性，并验证了列车的小半径曲线动力学性能。研究结果表明:提出的优化方法具有较快的计算速度，优化模型仅迭代了97次即可获得理想的钢轨打磨廓形；非对称打磨使内外钢轨具有差异性的打磨位置与打磨深度，将轮轨对中位置向轨道内侧移动了约10 mm，且不会改变轮缘处的轮轨匹配特性，有效增大了轮对横移10 mm范围内的轮对滚动圆半径差与轮轨接触角差，降低了列车在通过小半径曲线时的轮对横移、轮轨横向力、脱轨系数和轮重减载率，提高了转向架的横向稳定性和轮轨磨耗性能；虽然该打磨方式获得的钢轨廓形增大了轮轨接触应力，但并不会引起轮轨塑性变形。由此可见，该设计方法为提高列车的中小半径曲线通过能力提供了一种可行途径。 

Design method for asymmetric grinding profile of rails in sharp curves

For improving the performance of trains passing through sharp curves, the geometric derivation was performed on the profile of existing CN60 rails in China to design the target rail profile by asymmetric grinding. Taking the geometric parameters of the rail profile as design variables and the multi-body dynamics index of vehicle system as the comprehensive objective function, a multi-objective numerical optimization model for the asymmetric grinding profile of rails in sharp curves was proposed considering the rail grinding constraints. On the basis of the differential evolution algorithm, the corresponding numerical calculation program was written, and reasonable calculation parameters were selected to solve the optimization model. According to the actual line parameters, the wheel-rail contact geometric characteristics of the optimized grinding profile of rails were analyzed, and the dynamics performance of trains passing through sharp curves was verified. Research results reveal that the proposed optimization method is fast in calculations, and the ideal grinding profile of rails can be obtained after only 97 iterations of the optimization model. Due to the asymmetric grinding, the inner and outer rails have different grinding positions and grinding depths, and the centering positions of wheels and rails move to the inner side of rails by about 10 mm, without any change in the wheel-rail matching characteristics at the flange. This effectively increases the wheelset rolling radius difference and the difference in wheel-rail contact angles in the wheelset lateral displacement range of 10 mm, reduces the lateral displacement of wheelset, lateral wheel-rail force, derailment coefficient, and rate of wheel load reduction when trains pass through sharp curves, and improves the lateral stability of the bogie and the wheel-rail wear performance. Although the rail profile obtained by this grinding method increases the wheel-rail contact stress, it does not cause the plastic wheel-rail deformation. Therefore, this design method is feasible to improve the capability of trains passing through small- and medium-radius curves. 3 tabs, 16 figs, 31 refs.