动车组车轮疲劳性能数值仿真和评定方法研究

发布时间：2018-05-14 05:17

本文选题：数值模拟 + 疲劳强度评定　；参考：《中国铁道科学研究院》2014年博士论文

【摘要】：高速铁路显著缩短了出行时间，为旅客出行带来极大方便，我国已经具备高速铁路列车的自主研发和产业化生产能力，然而就其关键走行部件——车轮而言，目前主要依赖进口，这一问题影响并制约我国高速列车的国产化程度。研究和开发具有自主知识产权的动车组车轮，实现动车组车轮自主创新和国产化，对于降低车轮采购和运用检修成本、优化铁路资源配置等具有重要意义。开展动车组车轮疲劳性能数值仿真和评定方法研究是动车组车轮自主创新的关键环节，车轮服役性能与轮型设计、材质性能、热处理工艺、轮轨匹配及踏面伤损等诸多因素有关，是众多因素共同作用下的车轮综合表现；需要从车轮疲劳强度、热处理残余应力、轮轨接触强度、轮辋裂纹及其损伤容限等方面开展研究，分析各因素对车轮性能的影响。结合辐板裂纹萌生的物理特性和辐板表面应力特点，提出了以全尺寸车轮弯曲疲劳极限表征疲劳强度极限状态的主应力法和Crossland准则，并将二者结合提出了一种动车组车轮疲劳强度评定方法。在测试实物力学性能基础上拟合了车轮辐板S-N曲线和ε-N曲线，结合应力准则、应变准则、能量准则等3类准则和4个典型动车组车轮轮型开展了评定方法适用性分析。新方法评定效果的稳定性较强，适用于各型动车组车轮的疲劳强度评定，易于编程，适合工程应用。结合理论推导和试验，给出了车轮热处理模型中强制对流系数、相变潜热等关键参数的确定方法。建立了CRH5型动车组车轮整个热处理过程的温度场、应力场数值仿真模型，通过与实测温度和残余应力比较，对模型的正确性和可靠性进行了验证。首次定量给出了热处理残余应力和踏面镟修量的关系，以及二者对辐板疲劳强度的影响。分析发现，车轮热处理产生的残余应力有利于提高轮轨接触疲劳寿命，以CRH5-XP55车轮为例，热处理残余应力提高接触疲劳寿命的计算值约3倍以上。在实测真实应力-应变曲线、疲劳数据的基础上建立了弹塑性轮轨接触有限元模型和疲劳分析模型，开展了相关仿真计算。研究表明，具有良好轮轨接触几何关系的车轮踏面，一般也具有良好的轮轨接触应力分布规律和接触疲劳性能，综合考虑轮轨接触几何、等效锥度、强度薄弱点位置以及轮轨接触疲劳等性能指标，LMA踏面的综合性能最优。车轮轮型对接触疲劳寿命也有一定程度的影响，采用低径向刚度车轮可以在一定程度上提高轮轨接触疲劳强度。提出了一种塑性应力强度因子修正方法，并应用于轮辋裂纹损伤容限分析。提出了基于解析解的轮辋浅层裂纹的应力强度因子计算方法。结合有限元子模型技术和自适应网格划分技术，建立了轮辋内部埋藏型裂纹的任意三维裂纹扩展仿真模型。研究表明，直径不大于1mm的圆形面片裂纹对应的应力强度因子小于裂纹扩展门槛值，因此裂纹不会扩展。轮辋埋藏裂纹趋近于踏面表面时，裂纹耦合面趋近圆形；而裂纹远离踏面时，裂纹耦合面形状趋近椭圆并以车轮运行方向为长轴。在动车组的轴重范围内，轮辋内部萌生的裂纹扩展到一定尺寸后，裂纹深度对裂纹扩展速率的影响不显著。
[Abstract]:High speed railway significantly shortens the travel time and brings great convenience to passengers. China has the ability to develop and industrialization of high speed railway trains. However, its key walking parts, wheels, are mainly dependent on imports. This problem affects and restricts the degree of domestic high speed trains in China. It is of great significance to develop EMU wheels with independent intellectual property rights, and to realize independent innovation and localization of the wheels of the EMU. It is of great significance to reduce the cost of the wheel procurement and use the maintenance and optimize the allocation of railway resources.
The research on the fatigue performance simulation and evaluation method of the EMU wheel is the key link of the independent innovation of the wheels of the EMU. The service performance of the wheel is related to the wheel type design, the material performance, the heat treatment process, the wheel rail matching and the tread damage and so on. It is the comprehensive performance of the wheels under the joint action of many factors; it needs to be tired from the wheel fatigue. Strength, heat treatment residual stress, wheel rail contact strength, rim crack and damage tolerance were studied, and the influence of various factors on wheel performance was analyzed.
Combining the physical characteristics of the crack initiation and the surface stress characteristics of the spoke plate, the main stress method and Crossland criterion are proposed to characterize the ultimate state of the fatigue strength by the full size wheel bending fatigue limit, and a method for evaluating the fatigue strength of the EMU wheel is proposed by the combination of the two, and the vehicle is fitted on the basis of the mechanical properties of the test material. The S-N curve and the epsilon -N curve of the wheel spoke board, combined with the 3 types of criteria, such as stress criterion, strain criterion, energy criterion and so on, and 4 typical EMU wheel wheels, the applicability analysis of the evaluation method is carried out. The new method has strong stability, which is suitable for evaluating the fatigue strength of various types of EMU wheels, easy to program and suitable for engineering applications.
Combined with theoretical deduction and experiment, the key parameters such as forced convection coefficient and latent heat of phase change in the wheel heat treatment model are given. The temperature field of the whole heat treatment process of CRH5 type EMU wheel is established, and the numerical simulation model of stress field is established. By comparing with the measured temperature and residual stress, the correctness and reliability of the model are carried out. The relationship between the residual stress of heat treatment and the tread repair quantity and the effect of the two on the fatigue strength of the spoke plate are given for the first time. The analysis shows that the residual stress produced by the wheel heat treatment is beneficial to the increase of the contact fatigue life of the wheel and rail. The calculation value of the residual stress of the heat treatment to increase the fatigue life of the contact fatigue is about 3, with the CRH5-XP55 wheel as an example. More than twice.
On the basis of actual stress-strain curve and fatigue data, the elastoplastic wheel rail contact finite element model and fatigue analysis model are established, and the related simulation calculation is carried out. The research shows that the wheel tread with good wheel rail contact geometry relation is generally also with good contact stress distribution and contact fatigue performance of wheel rail contact. Considering the contact geometry of wheel and rail, the equivalent taper, the position of strength weak point and the wheel rail contact fatigue, the comprehensive performance of the LMA tread is the best. The wheel wheel type has some influence on the contact fatigue life, and the wheel rail contact fatigue strength can be improved to a certain extent by using the low radial stiffness wheel.
A modified method for plastic stress intensity factor correction is proposed and applied to the damage tolerance analysis of rim cracks. A calculation method of stress intensity factor for shallow rim cracks on the rim is proposed based on analytical solution. An arbitrary three-dimensional crack propagation in the inner rim of the rim is established by combining the finite element submodel technique and the adaptive mesh division technique. The simulation model shows that the stress intensity factor of a circular face crack with a diameter of not more than 1mm is less than the crack propagation threshold, so the crack will not expand. When the rim burial crack approaches the surface of the tread, the crack coupling surface approaches the circle; while the crack is far away from the tread, the shape of the crack coupling surface approaches the ellipse and runs on the wheel. In the axle load range of the EMU, the crack propagation to a certain size will not affect the crack propagation rate.

【学位授予单位】：中国铁道科学研究院
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U266

【参考文献】