重载铁路轮轨磨耗预测及钢轨型面优化研究

发布时间：2018-06-25 00:09

本文选题：重载铁路 + 车辆-轨道耦合动力学　；参考：《北京交通大学》2017年博士论文

【摘要】：重载铁路运输运能大、效率高、运输成本低,是世界铁路货物运输发展的共同趋势。在铁路轮轨系统存在的诸多病害中,车轮与钢轨的磨耗现象一直是最为普遍并且难以解决的问题。轮轨磨耗引起车轮与钢轨型面的改变,进而会导致轮轨接触状态和系统动力性能发生变化,对列车运行稳定性、安全性及系统各部件使用寿命都会产生较大影响。对于重载铁路而言,轮轨磨耗问题尤为突出,养护维修工作巨大,磨耗超过一定限度如果没有及时更换,则可能引起列车脱轨等重大事故。本文针对重载铁路发展过程中凸显出的轮轨磨耗问题,在对既有研究进行调研分析的基础上,创建了较完善的轮轨磨耗演化发展的数值仿真预测模型,可对实际运营条件下车轮和钢轨的磨耗分布特征、发展过程、规律进行分析预测。首次对轨道柔性在磨耗计算中的影响进行了探索研究。对关键参数、措施对于轮轨磨耗具体分布发展的影响规律进行了系统的研究。提出了一种新的钢轨型面优化数学模型方法,并采用此方法对重载铁路R75钢轨型面进行了优化设计,给出了R75钢轨优化型面。主要研究工作和成果如下:(1)创建了轮轨磨耗演化发展的数值仿真预测模型·针对轮轨磨耗问题目前的研究现状及存在的问题,对重载铁路轮轨磨耗演化过程的数值模拟进行了深入研究,提出并建立了整套的轮轨磨耗演化发展预测模型。模型由车辆-轨道耦合动力学计算、轮轨滚动接触分析、材料摩擦损失模型、复杂运营条件的模拟策略、型面更新自适应步长方法等内容组成。基于Archard材料磨损理论模型,在车辆轨道耦合动力学仿真和轮轨局部接触分析基础上进行轮轨接触斑磨耗深度分布计算;通过多工况仿真并引入无量纲的权重因子来实现对实际铁路复杂运营条件的合理模拟;采用了一种自适应步长算法进行轮轨型面的更新,可有效减少误差累积、改善数值模型的稳定性和可靠性。开展数值试验对轮轨接触斑网格密度对于粘着区滑动区分布、蠕滑力分布、轮轨磨耗深度分布、轮轨磨耗速率指标等的影响进行了系统分析,对磨耗模型中合理的接触斑网格密度取值进行了探讨。(2)针对既有研究空白,首次对软道柔性对于轮软磨耗计算的影响进行了探索研究·既有磨耗数值仿真研究中均未考虑轨道柔性的影响,针对此研究空白,本文对柔性轨道对轮轨磨耗的影响进行了探索研究。首先,基于Pearce-Sherratt摩擦功磨耗理论建立了一种简化的轮轨磨耗计算模型,以提高磨耗计算速度。通过与所建立的精确磨耗模型对比,对简化模型的合理性进行了验证。然后基于有限单元浮动坐标方法(FE/FFR)建立柔性轨道模型,通过缩减模态技术减少钢轨振动变形模态坐标数目、消除高频模态以减小计算代价。然后通过合理的轮轨接触算法和钢轨几何型面更新策略实现车辆系统与柔性轨道系统的动力学耦合。最后基于所建模型通过数值试验明确了理想轨道条件下和不平顺轨道条件下柔性轨道对于轮轨磨耗发展的影响特性。(3)系统研究掌握了实际运营条件下重载铁路车轮及钢轨磨耗演化发展规律。通过系统的仿真分析,掌握了重载铁路直线地段和曲线地段钢轨的磨耗分布特征和发展规律、以及车辆通过曲线条件下不同位置车轮的磨耗分布发展特性,同时也验证了所建立的磨耗预测模型的合理性。并对大秦铁路实际线路运营条件下重载车辆各车轮的实际磨耗发展过程进行了数值仿真预测。(4)率先对关键材料、结构参数及措施对于轮轨磨耗分布发展的影响规律进行了系统研究,为线路设计、运营、养护提供了理论依据和参考。设计开展了系统的数值试验,对轮轨材料硬度、钢轨轨底坡、货车轴重、运行速度等主要的材料结构参数及钢轨润滑等减磨措施对于轮轨磨耗水平以及具体分布发展状况的影响规律、特点进行了系统研究,并提出了系列的建议和原则。为线路设计、运营管理及养护维修提供了理论依据和参考。(5)提出了一种新的钢轨型面优化模型方法,并给出了重载铁路R75钢轨优化型面,可有效改善轮轨动力相互作用,减缓磨耗发展。对重载铁路钢轨型面的优化设计问题进行了深入研究,提出了一种新的钢轨型面优化数学模型方法。将钢轨型面参数化处理,表示为一系列离散点坐标变化量的广义函数。然后以所有可能轮轨接触情形下接触点附近轮轨型面共形度最高为原则设计优化目标函数。在目标函数构造过程中,编制了轮轨接触几何算法以实现轮轨接触点位置的快速探测。为了满足一些基本限制,施加了一系列线性/非线性约束条件。这样,将钢轨型面优化问题创新性地抽象为一个典型的单目标多变量多约束非线性数学优化问题。采用序列二次规划算法(SQP)结合拉格朗日方程、拟牛顿方法实现对此优化模型的快速准确求解。基于所建立的优化模型,对我国重载铁路R75钢轨型面进行优化设计以更好地匹配LM型车轮型面,并提出了 R75优化型面。分别从型面几何特征、轮轨接触几何关系、车辆-轨道系统动力学性能并最终从轮轨磨耗发展方面对优化型面和原始型面进行了系统的对比分析。结果表明,优化型面可有效改善轮轨接触几何关系及动态相互作用,有效减缓轮轨磨耗的发展,可考虑作为我国重载铁路钢轨设计的一个较好的选择。
[Abstract]:Heavy haul railway transportation has large transportation energy, high efficiency and low transportation cost. It is a common trend in the development of railway freight transportation in the world. In many diseases of railway wheel rail system, the wear phenomenon of wheel and rail has been the most common and difficult to be solved. Wheel rail wear causes wheel and rail profile change, which will lead to wheel and rail. The change of the contact state and the dynamic performance of the system will have great influence on the train running stability, safety and the service life of the components of the system. For heavy haul railway, the wheel rail wear problem is particularly prominent, the maintenance and maintenance work is great, and the wear over a certain limit, if the fruit is not changed in time, may cause the train derailment and so on. In this paper, aiming at the wheel rail wear problem highlighted in the process of heavy haul railway development, based on the research and analysis of the existing research, a more perfect numerical simulation prediction model of wheel rail wear evolution and development is established, which can be used to analyze the wear distribution characteristics, development process and law of wheel and rail under actual operating conditions. The influence of the track flexibility in the wear calculation is explored for the first time. The effect of the key parameters and measures on the development of the wheel rail wear specific distribution is systematically studied. A new mathematical model method for the rail surface optimization is put forward, and the method is used to optimize the R75 rail surface of the heavy haul railway. The optimized surface of R75 rail is given. The main research work and achievements are as follows: (1) the numerical simulation prediction model of wheel rail wear evolution and development is created. In view of the current research status and existing problems of wheel rail wear, the number value simulation of wheel rail wear evolution process in heavy load railway is deeply studied and set up and set up. The model is composed of vehicle track coupling dynamic calculation, wheel rail coupling dynamics calculation, wheel rail rolling contact analysis, material friction loss model, complex operation condition simulation strategy, model surface updating adaptive step length method and so on. Based on Archard material wear theory model, vehicle track coupling dynamics simulation and wheel On the basis of local contact analysis of rail, the depth distribution of wheel rail contact spot wear is calculated. A reasonable simulation of the complex operating conditions of the actual railway is realized through the simulation of multiple working conditions and the introduction of the dimensionless weight factor. An adaptive step length algorithm is used to update the wheel rail profile, which can effectively reduce the accumulation of errors and improve the numerical model. The numerical test is carried out to carry out a systematic analysis on the influence of wheel rail contact spot grid density on the sliding zone distribution, creep force distribution, wheel rail wear depth distribution, wheel rail wear rate index and so on. The reasonable contact spot grid density value in wear model is discussed. (2) there are both research space. In white, the influence of soft channel flexibility on the calculation of wheel soft wear was explored for the first time. The influence of orbital flexibility was not considered in the numerical simulation of existing wear. The effect of flexible track on wheel rail wear was explored in this paper. First, the theory of friction work wear based on Pearce-Sherratt was established. The simplified model of wheel rail wear calculation is introduced to improve the speed of wear calculation. The rationality of the simplified model is verified by comparing with the exact wear model established. Then the flexible track model is established based on the finite element floating coordinate method (FE/FFR), and the number of modal coordinates of the rail vibration deformation is reduced by reducing the mode state technology. In addition, the high frequency mode is used to reduce the computational cost. Then the dynamic coupling of the vehicle system and the flexible rail system is realized by the rational wheel rail contact algorithm and the rail geometry surface updating strategy. Finally, based on the numerical test, the flexible track for wheel rail wear and rail wear under the ideal track condition and the uneven track condition is determined. (3) the system research has mastered the evolution and development law of heavy load railway wheels and rail wear under the actual operating conditions. Through the system simulation analysis, the wear distribution characteristics and development rules of the rail in the heavy load railway line and the curve section are mastered, as well as the wear of the wheels in different positions under the curve conditions. It also verified the rationality of the established wear prediction model, and carried out numerical simulation prediction on the actual wear development process of the wheel of heavy load vehicles under the actual line operation condition of Daqin Railway. (4) the influence law of key materials, structural parameters and measures on the development of wheel rail wear distribution was carried out. The system research provides a theoretical basis and reference for the design, operation and maintenance of the line. A systematic numerical test is designed and carried out to influence the wheel rail material hardness, the rail rail bottom slope, the axle load of the freight car, the running speed and other main material structure parameters and the rail lubrication to reduce the wear level and the specific distribution development of the rail lubrication. Law and characteristics have been systematically studied, and a series of suggestions and principles are put forward. It provides a theoretical basis and reference for line design, operation management and maintenance. (5) a new method of rail surface optimization model is proposed, and an optimized rail surface for heavy rail R75 rail is given, which can effectively improve the interaction of wheel and rail dynamic and slow down wear and wear. The problem of optimal design of rail profile surface for heavy haul railway is deeply studied. A new mathematical model method for rail profile optimization is proposed. The parameterized rail surface is parameterized as a generalized function of a series of discrete point coordinates. In order to satisfy some basic constraints, a series of linear / nonlinear constraints are applied to meet some basic restrictions. In order to meet some basic restrictions, a series of linear / nonlinear constraints are applied. Thus, the optimization of rail surface optimization is abstracted to a typical one. The single objective multivariable and multi constraint nonlinear mathematical optimization problem is solved by using the sequential two order programming algorithm (SQP) combining the Lagrange equation and the quasi Newton method to solve this optimization model quickly and accurately. Based on the established optimization model, the optimal design of R75 rail surface in heavy haul railway in China is designed to better match the LM wheel type surface. The optimized surface of R75 is put forward. The geometric characteristics of the surface, the contact geometry of wheel and rail, the dynamic performance of the vehicle track system and the ultimate surface of the wheel rail wear are compared and analyzed. The results show that the geometric relationship and dynamic interaction of the wheel and rail contact can be effectively improved by the optimized surface. The effective development of wheel rail wear can be considered as a better choice for rail design of heavy haul railways in China.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U211.5

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