【作者】 温泽峰；

【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， 2006， 博士

【摘要】 钢轨波浪形磨损(简称波磨)是铁路工业界难以解决的技术问题。人们对它的观察和研究已有一百多年的历史。虽然人们通过理论和数值方法对钢轨波磨初始形成和发展机理的认识有了很大的进展,但是迄今为止还没有一种广泛认同的统一有效的理论模型来解释波磨初始形成机理和影响波磨发展的因素。随着列车速度、轴重的提高、车流密度的加大和新型机车车辆结构的推广使用,钢轨波磨现象变得日趋严重,因而导致较高的铁路运输成本,直接影响铁路运输安全。钢轨波磨导致车辆轨道结构激烈的振动并产生噪声,不仅影响旅客乘坐的舒适度和装运货物的完整,而且缩短结构部件的使用寿命。因此,开展钢轨波磨的研究具有很强的理论意义和工程应用背景。 受到国家自然科学基金重点项目“轮轨滚动接触表面波浪形磨损和滚动接触疲劳的研究”(59935100)、国家自然科学基金面上项目、高等学校全国优秀博士学位论文作者专项基金和西南交通大学博士生创新基金等项目的资助,本文主要开展了以下几方面的研究工作: (1) 首先对国内外钢轨波磨的研究历史和现状进行了详细论述,明确了钢轨波磨研究的意义和研究方向。 (2) 建立了较为完整的钢轨磨耗型波磨理论计算模型,模型中包含了车辆一轨道垂向横向耦合动力学理论模型、轮轨材料摩擦磨损模型和改进的三维非赫兹滚动接触理论模型,并发展了相应的数值程序。该模型是目前国内外最完整最复杂的钢轨波磨计算模型,突破了已有方法仅考虑轮轨垂向耦合振动对钢轨波磨形成的影响和仅借助赫兹滚动接触理论进行型面损伤计算的局限性。用它不仅可以计算一个车轮和钢轨动力行为与摩擦磨损的循环作用过程,还可以同时计算半个车体一个转向架四个车轮和钢轨动力耦合作用与摩擦磨损的循环作用过程。利用该模型详细分析计算了各种可能的轨道缺陷对钢轨波磨形成和发展的影响,得到了大量的数据结果,这些结果对进一步认识钢轨波磨初始形成与发展机理和解决钢轨波磨问题有重要的参考价值。使用1:1试验装置对钢轨磨耗型波磨计算模型进行了试验验证。钢轨磨耗型波磨理论模型与试验结果吻合较好。 (3) 针对过去人们进行滚动接触应力分析只局限于稳态的情形,本文建立了二维弹塑性非稳态滚动接触有限元模型。模型中材料本构采用能较好描述材料棘轮效应的循环塑性模型。分别研究纯滚动、全滑动、牵引滚动和多步载荷条件下钢轨的残余应力、应变和变形,得出了钢轨材料在反复滚压条件更多还原

【Abstract】 Rail corrugation is one of the most serious problems in railway engineering. The phenomena of rail corrugation has been observed and studied for over 100 years. Although much progress on the recognition of the mechanisms of initial corrugation formation and development has been made with theoretical and experimental methods, the studies on corrugation have not explained the mechanism of its initial formation perfectly, and have not formulated a united and validated mathematical model to explain the initial formation mechanism and the factors affecting the evolution of rail corrugation so far. With increases of train speed, axle load, traffic density and the introduction of new vehicles, etc., the phenomenon of rail corrugation shows a tendency to increase. Therefore a great deal of money is spent every year by railway transportation companies on the maintenance and replacement of corrugated and broken rails. The railway transportation security is directly endangered. Rail corrugation causes fierce vibrations of the structures of both railway vehicle and track, noise, discomfort for passengers and residents living near the tracks, damage for goods and reduction of the use life of structural parts. Therefore studies on rail corrugation are very important from the practical and cognitive points of view.Supported by the Natural Science Foundation Committee of China (Nos. 59935100, 50375129 and 50575188), the Foundation of Ph.D. Student Education of Education Ministry of China (No.20020613001) and the Special Foundation for Excellent Ph.D. Thesis, the main research work in the present dissertation involves:(1) The studies on rail corrugation in the past and now in the world are reviewed. The significance and research orientation of rail corrugation are indicated.(2) A rail corrugation calculation model due to wear mechanism is established, which considers a combination of Kalker’s non-Hertzian rolling contact theory to be modified, a rail material wear model and a vertical and lateral coupling dynamics of half a passenger car and a curved track. A corresponding numerical program is developed. The corrugation model is more completed and complicated as compared with other ones appeared in published papers. The developednumerical program can consider a feedback process not only between the rail wear and the transient coupling dynamics of one wheel and the curved track, but also between the rail wear and the transient coupling dynamics of four wheels of a same bogie and the curved track. The effect of rail defects on the formation and development of rail corrugation is investigated in detail. A lot of numerical results are obtained. Theses results help understand the mechanism of corrugation initiation and development and settle the corrugation problem. The corrugation model is validated by experiment using a full-scale test facility. The test results are in good agreement with the numerical results.(3) Most of previous stress analyses of rolling contact assumed a constant normal pressure. The current work presents a two-dimensional elastic-plastic finite element model of non-steady state rolling contact. The general cyclic material behavior including cyclic strain ratcheting and stress relaxation that occur under rolling contact is taken into account. The effects of different conditions of pure rolling contact, full slip and partial slip rolling contact and multiple step loading on residual stresses and strains are considered. The developments of rolling contact stresses, strains and deformations are obtained for repeated rolling contact. The results indicate that studies of rolling contact fatigue and the initiation and development mechanism of surface corrugation or ripple should take non-steady state and cyclic strain ratcheting effect into consideration.(4) A rail corrugation calculation model due to plastic deformation is established, which considers a combination of Carter’s two-dimensional rolling contact theory, the elastic-plastic finite element model of non-steady state rolling contact and a vertical dynamics model of one quarter of a car coupled with a curved track. The model involves a concept of feedback between the uneven running surface plastic deformation and the contact vibration of wheel and track. The ratcheting effect of rail material under repeated rolling contact and the effect of residual deformation accumulation on corrugation are considered. The formation and development of rail corrugation due to plastic deformation under non-steady state loading are studied. The influence of a scratch on rail on the initiation and evolution of the plastic deformation induced rail corrugation is investigated. The evolution rule of an initial corrugation with an increase of car passage is analyzed. Detailed material performances under the trough and crestsuch as stresses, strains and plastic flow rate are obtained.(5) According to field survey and statistical analysis of the number of damage rails, the phenomena of rail squashing and cracks in rail joint region are one of the main problems in heavy haul lines and mountainous lines in China. The rail joint is always an origin of the initiation and development of rail corrugation. In this thesis, three-dimensional nonlinear finite element dynamic analysis code ANSYS/LS-DYNA3D is used to establish an elastic-plastic finite element model of three-dimensional contact and impact of wheel and rail. Mutibody contact problem is taken into consideration in the model. The wheel-rail contact-impact process during the wheel running over the rail gap is simulated. The distribution of stresses and strains in the jointed rail head are given. The influences of axle load, train speed, yield stress and tangent modulus of rail material on the stresses and strains are investigated in detail. The study would provide a method and useful datum for further research on the mechanism of impacting damage on railhead at jointed rails and improving the rail joint mode.更多还原