【作者】 王彩芸；

【导师】 刘启跃；

【作者基本信息】 西南交通大学 ， 机械设计及理论， 2013， 博士

【摘要】 钢轨作为轮轨系统的重要组成部分,是发展高速、重载以及实现繁忙铁路运输的基础。然而钢轨断裂、波浪形磨损、压溃以及疲劳裂纹扩展等摩擦磨损问题造成的列车脱轨、振动等问题已造成了巨大的人力、物力和材料的损失,钢轨的摩擦磨损问题已成为制约铁路发展的重要问题。研究钢轨的摩擦磨损产生的机理以及影响因素,对减缓钢轨磨损,延长其使用寿命具有重要的现实和经济意义。论文采用实验研究方法从微观和宏观两方面研究钢轨材料的机械性能与摩擦磨损特性,得到了一些磨损量和硬度值；同时采用Kalker的三维弹性体非赫兹滚动接触理论模型和弹性理论的相关知识,为利用摩擦功预测钢轨磨损量提供理论基础。基于实验研究提供的磨损量参考值和理论分析的结果,采用利用轮轨摩擦功和偏最小二乘法分析两种方法预测钢轨磨损量,为研究钢轨磨损量提供一定的参考价值。取得的主要结果和结论如下：(1)微观与宏观实验结果表明,钢轨材料的摩擦磨损性能对其机械性能具有很强的依赖性,即U71Mn钢轨硬度低,强度较PD3钢轨低,耐磨性能较差。(2)钢轨宏观磨损量与列车轴重呈线性增长关系；随曲线半径和列车运行速度的增大,磨损量呈非线性减小趋势发展；在车速小于160km/h,曲线半径小于1200m工况下,磨损量变化速度较快。(3)随着循环次数增加,轮轨磨损量均增大,但车轮磨损量的增加量大于钢轨增加值,钢轨磨损量随着循环次数增加呈线性增长趋势,而与之配对的车轮磨损量呈曲线趋势增加。在相同的循环时间段内,U71Mn轮轨接触副磨痕宽度、深度以及表面不平度均要较PD3轮轨副大。(4)轮轨接触斑粘/滑区面积比重相等点随着夕,(?)和(?)增大向着横移量降低的方向移动,随着摩擦系数增大逐渐向着横移量增大的方向移动。在纯机械载荷作用下,最高应力、等效应力、最高塑性应变和剪应力均产生于易使轮轨材料产生破坏表层位置。(5)基于宏观实验和数值分析基础,利用摩擦功和偏最小二乘法回归两种方法,得到钢轨和磨损量关于随轴重、曲线半径和车速变化的经验公式,对实验室和现场进步研究轮轨磨损问题和预测钢轨磨损量有参考价值。更多还原

【Abstract】 As an important component of wheel/rail system, steel rail plays an important role in of the development of high-speed and heavy-haul railway transportation. However, as the derailment, vibration and other problems of trains caused by friction and wear, such as rail fracture, corrugation, crushing and fatigue crack propagation, have led to great losses of manpower and materials. The friction and wear of steel rail has become a main restricting factor for the development of railway. Therefore, it is of important economic and realistic significance to study the wear mechanism and factors of steel rail to decrease its wear rate and prolong its service life.In this paper, experimental methods of both micro-scale and macro-scale were used to investigate the mechanical and triboloigical properties of rail materials. Numerical calculation was also conducted using Kalker’s non-Hertzian rolling contact theory of three dimensional elastic bodies, aiming to provide a theoretical basis for the wear prediction of steel rail based on friction work. Based on the experimental data and the results of calculation, the wear volume formulas of steel rail were explored by means of friction work of rail-wheel and PLS. Main conclusions were drawn as follows:(1) The tribological behavior of steel rail depended strongly on its mechanical properties. Owning lower hardness, lower intensity, and U71Mn rail material exhibited poorer wear-resisting performance compared to PD3rail material.(2) There exist a linear relation between the wear loss of rail and the axle load of trains. With curve radius and train speed increasing, the wear rate of rail reduced nonlinearly. The wear rate changed rapidly especially when the speed was no more than160Km/h and curve radius less than1200m.(3) As the number of cycles increased, the wear volume of steel rail increased linearly, while the wheel exhibited a nonlinear increase in the wear volume. And the increase rate of wear volume was higher for wheel than for steel rail. Compared with PD3rail, a wear scar with bigger width and depth and uneven surface appeared on the surface of U71Mn rail.(4) With the increase of y, φ andφ, the adhesion/slip area equivalence point of the contact zones of rail/wheel moved forward the direction where lateral displacement reduced. But the point moved forward the direction where lateral displacement increased with the increase of friction coefficient. For sliding condition, the maximum value of normal stress, equivalent stress, plastic strain, and shear stress, were observed in the surface layer where the damage of wheel/rail material easily occurred under the action of mechanical loading.(5) Based on the experimental data and the results of numerical calculation, empirical equations of the variation of the wear loss of steel rail versus axle load, curve radius and wheel speed were established by means of friction work of wheel-rail and PLS respectively. The equations would be helpful to further studies on the wear of wheel/rail and the prediction of rail’s wear volume of both in the laboratory and in the field.更多还原