面向磨耗和应力的曲线钢轨廓形优化设计

Optimal Design of Curved Rail Profile for Wear and Stress

为了缓解重载曲线钢轨易出现的磨耗严重、接触应力大的问题,建立曲线钢轨廓形非对称优化设计方法,分析优化策略对轮轨磨耗和轮轨接触应力的影响。基于车辆-轨道动力学理论、轮轨磨耗理论、赫兹接触理论、遗传优化算法、层次分析法,以钢轨廓形离散点坐标为优化变量,以车辆动力学性能指标和钢轨几何特征为约束条件,以磨耗和应力作为优化目标,获得曲线钢轨廓形非对称优化设计方法。运用该方法研究在优化迭代中只考虑磨耗、只考虑应力和同时考虑磨耗-应力的三种优化设计策略。结果表明,与现场实际钢轨廓形相比,只考虑磨耗的设计策略会导致应力上升24%,综合评价指数上升8%;只考虑应力的策略会导致磨耗上升149%,综合评价指数上升258%;同时优化磨耗和应力的策略使磨耗和应力分别下降32%和22%,综合评价指数下降17%;最优钢轨廓形在能够提供较大轮对横移量的同时并没有加剧轮缘磨耗,更有利于曲线通过;随着速度和载重的增大,最优钢轨廓形的磨耗指数、接触应力以及脱轨系数等性能指标相比实测廓形更小。

In order to alleviate the phenomenas of the severe wear and large contact stress of the heavy-haul curve rails, the method is established about the asymmetric optimization design of curve rail profiles, which analyzes the influences of the different optimized strategies on the wheel-rail wear and contact stress. Based on the vehicle-track dynamics theory, wheel-rail wear theory, Hertz contact theory, genetic algorithm, and analytic hierarchy process, the method set the coordinates of discrete points of the rail profile as optimization variables, set vehicle dynamics performance indicators and rail geometric characteristics as constraints. With wear and stress as the optimization targets, a symmetrical optimization design method of curved rail profiles is obtained. The above method to study three optimization design strategies which only consider wear, stress only and wear-stress at the same time are studied in the optimization iteration. The results show that, compared with the actual measured rail profile on site, the strategy, only considered wear,causes the stress to rise by 24%, and the comprehensive evaluation index rises by 8%. The method, only considered stress, causes the wear to rises by 149%, and the comprehensive evaluation index rises by 258%. The method of optimizing the wear and stress in the same time makes the wear drop by 32%, makes the stress decrease by 22%, and the comprehensive evaluation index drops by 17%.The optimal rail profile curve passing performance and vehicle running adaptability perform well. The optimal rail profile does not aggravate the wheel flange wear while providing a larger wheelset lateral displacement, which is more conducive to curve passing.With the increase of speed and load, the wear index and contact stress and derailment coefficient are smaller than those of the measured profile.