【作者】 李霞；

【导师】 金学松；

【作者基本信息】 西南交通大学 ， 载运工具运用工程， 2012， 博士

【摘要】 一个多世纪以来,钢轨波磨引起了铁路工作者的广泛注意和研究兴趣,然而人们却一直没有总结出治愈波磨的根本方法。一个公认的事实是：不同类型的波磨其形成机理也不同,因而很难用某一种方法完全治愈钢轨波磨。但是部分类型的钢轨波磨也可以通过相应的措施得到很好地预防。随着城市轨道交通的不断发展,我国地铁发展迅速,与此同时,各个城市的地铁线路都出现了不同程度的波磨。地铁钢轨波磨的形成机理十分复杂,至今尚未完全弄清楚。它的研究涉及多学科多领域的相关知识,如结构动力学、固体接触力学、滚动接触理论、摩擦学、计算方法等。因此,深入研究地铁钢轨波磨问题是十分重要的,揭示其形成机理并提出相应的波磨减缓措施,对确保我国地铁车辆安全运行和城市轨道的减振降噪具有重要意义。我国某地铁线路开通不久后,整个线路多种轨道形式上均出现严重的钢轨波磨,其不仅引起了车辆轨道结构的强烈振动,还带来了恼人的环境噪音,引起了乘客和附近居民的强烈不满。因此,本文对该地铁线路钢轨波磨的形成机理及其相关的减磨措施展开详细的研究和探讨,主要包括：(1)简单介绍了城市轨道交通的发展概况,对轨道交通发展过程中出现的钢轨波磨问题进行了简单论述,对地铁波磨的研究现状做了详细的综述,指出了钢轨波磨研究的重要性。(2)详细介绍某城市地铁车辆轨道结构特征、典型区段钢轨波磨状态和轨道结构特性测试结果,对钢轨波磨通过频率与轨道结构振动频率的相互关系做了详细探讨,发现该线路上出现的波磨主要与轨道结构形式相关。(3)建立了车辆簧下质量与多种轨道耦合作用的三维实体有限元理论分析模型,分析讨论了轨道结构的动态特性与波磨发生发展的相互关系,给出了各种轨道形式波磨形成机理的初步解释。(4)建立了地铁车辆-无砟轨道钢轨耦合作用下的波磨理论分析模型,模型集成了考虑刚柔特性的整车-无砟轨道垂横向耦合动力学模型、改进的轮轨非Hertz滚动接触模型、轮轨材料摩擦磨损模型和钢轨波磨磨耗叠加模型。该模型可以考虑整车车辆轮轨之间的动力作用对钢轨波磨形成和发展的影响,以及波磨导致钢轨表面不平顺发生变化后其对轮轨接触和动力学的反激励作用,即整个大模型可以考虑车辆轨道瞬态动力作用行为与轮轨磨耗的往复循环相互作用过程。动力学耦合模型中,车辆结构采用多刚体质量块—弹簧—阻尼系统来模拟,钢轨采用铁木辛柯梁模型,轨道板采用三维实体有限元来模拟,更加真实地反应了轨道结构的特性；滚动接触模型中考虑了磨耗逐步累积的钢轨波磨对轮轨接触的影响；材料摩擦磨损模型采用考虑自旋效应的摩擦功磨耗模型；波磨磨耗叠加模型可以同时计算整车车辆8个车轮与钢轨相互作用所形成的磨耗。(5)详细介绍某地铁现场波磨的发展情况,掌握了该地铁特定轨道形式上波磨的发展规律。结合现场跟踪的实测结果,对本文的理论模型进行了试验验证,仿真计算结果表明该模型能够能客观地反应实际情况,其模拟结果和现场调查情况相吻合。(6)研究了白噪声激励、复合不平顺激励和凹坑激励下普通短轨枕曲线轨道和科隆蛋减振直线轨道钢轨波磨的形成机理和其发展情况。研究结果表明,普通短轨枕轨道结构在60Hz～90Hz范围内钢轨和轨道板整体相对于路基的垂向弯曲振动是125mm～160mm波磨产生的根本原因；数值结果显示在多种激励下,普通短轨枕轨道内外轨波磨的显著波长与现场情况相一致。科隆蛋(Cologne)减振扣件轨道在160Hz～300Hz的钢轨垂向弯曲振动和钢轨扭转振动是形成40mm～50mm波磨的根本原因；数值结果显示在多种激励下,科隆蛋减振扣件轨道左右轨波磨的显著波长与现场情况相一致。数值结果还表明,钢轨波磨的形成与随机不平顺中的初始波长关系较小,与轨道结构自身的固有特性以及车辆通过速度关系较大,只有初始不平顺中的波长与波磨通过频率对应波长相近时,其才能发展成波磨,否则其会在轮轨的碾压过程中消失。(7)研究了扣件参数、曲线超高、车辆载重和摩擦系数对钢轨波磨的影响,并提出了相应地减缓措施。研究结果表明,随着扣件参数的增大,科隆蛋减振轨道的敏感频率发生偏移,波磨的波动幅值明显减小,且钢轨波磨的发展速度也比较缓慢；适当地减小小半径曲线过超高值,以及设置较小的欠超高有利于减缓曲线轨道钢轨波磨形成和发展速率；相同条件下,高峰期车辆通过波磨轨道时所形成的均匀磨耗偏大,而非高峰期车辆形成的非均匀磨耗偏大,即波磨更严重；在保证正常牵引制动需求的情况下,轮轨摩擦系数控制在0.35以下时,钢轨波磨的发展速度能够得到很好的控制。更多还原

【Abstract】 Rail corrugation has excited the interest of railway researchers for more than a century. But there is not a good cure for it. It has been realized that different type of corrugation arises from different mechanism, and some types of corrugation can indeed be prevented through proper method. Now, rail corrugation appears on many metro lines. The mechanism of subway rail corrugation is complex and it is still not fully understood. Its research involves many subjects and multi-field knowledges, such as structural dynamics, rolling contact theory, tribology, material science, computational method, etc. Therefore, it is very important to carry out in-depth research on rail corrugation in metro system so as to understand the formation mechanism and then propose the corresponding mitigation measures, which is of great significance for ensuring the safe operation of metro vehicles and urban railway noise and vibration reduction.Rail corrugation has caused serious problems on a Metro line shortly after the operation, which not only caused strong vibration of the vehicle and track, but also brought annoying ambient noise, and aroused strong dissatisfaction of passengers and nearby residents. Aiming at investigating the formation mechanism and mitigation measurements of rail corrugation, the present paper conducts a detailed study on the following aspects.(1) A brief overview of the development of urban rail transit and the accompanied corrugation problem is presented. The studies on subway corrugation are reviewed in detail. The importance of study on rail corrugation is pointed out.(2) The thesis gives a detailed description of the characteristics of vehicle-track structure of the selected Metro line, rail corrugation on the typical sections, and obtained test results of track structure. The relationship between the natural frequencies of the track structure and the passing-frequencies of the existing corrugations is investigated. It shows that the corrugation occurrence has nothing to do with the wheelset twist resonance and mainly corresponds to the characteristic of the track structure.(3) The3D FEM mod is developed. The model considers the coupling effect of the vehicle unsprung mass and the track structure. Using the model finds the relationship between the mode shapes and the corresponding resonance frequencies of the track structure and the corrugations. The preliminary explanation of the formation mechanism of corrugation on different track structure is presented.(4) A rail corrugation model for the metro vehicle and the slab track is developed. It considers a combination of the coupling dynamics model of a whole vehicle and track, the modified Kalker’s non-Hertzian rolling contact model for wheel and rail, a material wear model and a accumulated wear model. It considers not only the effect of wheel/rail transient dynamic interaction on the formation and development of corrugation, but also the effect of the accumulated corrugation on the wheel/rail contact and coupling dynamics. That is, this model can take into account a feedback process between the long-term effects of the rail corrugation and the transient coupling dynamic of whole vehicle. In the coupling dynamic model, the vehicle is treated as a full rigid multi-body system; the rail is modeled with a Timoshenko beam resting on discrete rail pads. The slab is modeled as a three-dimensional flexible structure based on finite element method. The effect of the accumulated corrugation on the wheel/rail contact is considered in rolling contact model. The material model is based on the frictional work which considers the spin effect. The accumulated wear model can superimpose the corrugation formed due to the interaction between the8wheels of the whole vehicle and the rails.(5) Extensive filed measurements of rail corrugation are carried out and analyzed in detail. The developed corrugation model is validated by using the tracking test results and the validation shows a good agreement between the results of the test and the calculation by the model.(6) The formation and development mechanism of corrugation on the tracks with fix-dual short sleepers and Cologne fastenings is investigated through the numerical simulation which calculates the response of the wheel/rail system to the excitations of white noise, mixed-sin irregularities and dent defect. The obtained results are as follows:①the resonant in the band of60Hz-90Hz of the fix-dual short sleepers track is an underlying cause of the125mm-160mm wavelength corrugation, and indicates that the rail together with the slab vibrates with respect to the subgrade in vertical direction.②the resonant in the band of160Hz-300Hz of the Cologne fastenings track is the root cause of the40mm-50mm wavelength corrugation. The resonant includes the vertical bending vibration and the torsional vibration of the rail, with respect to the slab.③the calculated wavelengths of corrugation are consistent with the measured results.④the formation of corrugation is mainly influenced by the inherent characteristics of track structure and vehicle speed.⑤the track irregularities can develop into rail corrugations only when the passing frequencies of their wavelengths are close to the frequencies of the track resonances to be easily excited. Otherwise, they will disappear gradually in the wheel/rail rolling contact process.(7) The effect of fastener parameter, curve superelevation, vehicle load and friction coefficient on the rail corrugation formation is also investigated through the numerical simulation, and the corresponding mitigation methods are proposed. The numerical results show that with the increase of fastener parameter the sensitive resonance frequencies of the Cologne track are changed and the fluctuating amplitude at the passing frequency of the corrugation significantly decrease and the development speed of the corrugation is quite slow. An appropriate reduction in the superelevation can slow down the formation and development rate of corrugation. When passing over the corrugated rail, the vehicle in non-peak results in larger non-uniform wear compared to the vehicle in peak, that is, the corrugation resulting from the vehicle in non-peak is more serious. On the premise of ensuring the braking and traction requirements, the friction coefficient less than0.35can effectively controls the development of rail corrugation.更多还原