高速列车轮对旋转走行动力行为及安全性理论和工程应用研究

When the velocity of the high speed Electrical Multi-Unit (EMU) reaches upto some figures, the work velocity of the wheelsets is higher than its first critical rotation speed, and the wheelset must be dealt with an elastic rotor to investigate the operation safety and the reliability of the EMU-track system. By use of some theories such as railway vehicle system dynamics, rotor dynamics, structural strength and vibration, an elastic high-speed EMU-track dynamic coupling model will be established and be verified by filed test data. The elastic displacement of rotating wheelset, gears mesh vibration and wheel/rail rotation contact are included in the coupling model. .With the help of mathematics simulation and analysis, the wheel/rail contact relationship and dynamic behaviour will be investigated to obtain the influence of the elastic displacement, gear meshing vibration and rotation speed of the wheelset on the wheel/rail creep, adhesion, moving, non-uniform wearing and the critical velocity of the EMU. The operation stability of the rotating wheelset will be studied and the effects of the axle flexibility, axle spring stiffness and wheel/rail constrain on its critical rotation velocity will be presented and the reasonable rigidity of the wheel axle for different design speed will be offered. The influence of the elastic displacement of the wheelset caused by unbalance mass and forces on the operation safety of the wheel/rail system will be researched and all of the safety indexes such as derailment coefficient, decrease load ratio and maximal forces will be investigated. The effect of the wheelset faults such as wheel flat and out-of-round profiles on the system dynamics will be studied and some combined conditions including wheel faults, unbalance mass and elastic displacement of the wheelset on the operation safety of the EMU and the reliability of the wheel axle will be investigated when the high speed train passes turnout and curve. Moreover, the characteristics and radial distribution of the stress at the assembled sections of the rotating wheel axle will be examined when the train runs on some combined conditions and the reasonable assemble forces of the wheelset for different operation speed will be suggested. .It is very useful of the project to widen the railway vehicle-track system dynamics and to master the design theories and methods of the high-speed wheelset of China, and it is helpful to investigate the abnormal dynamics and failure mechanism of the bearings of the high speed wheelset.

列车速度提高到一定程度后，高速旋转轮轴进入挠性转子范畴。结合车辆动力学、转子动力学及结构强度等理论，在建立包含轮对弹性振动、旋转走行关系和齿轮啮合振动的全弹性高速车辆-轨道系统动力学模型并验证的基础上，①研究轮轴弹性变形和截面转角下的轮轨接触、蠕滑、走行和非均匀磨耗等动力行为，揭示高速轮对弹性变形对轮轨蠕滑、黏着和临界速度影响机理；②研究高速旋转轮对稳定性，获得轮对临界转速与轮轴刚度、轮轨约束和轴箱弹性约束之间关系；③研究多种最不利组合工况轮轨安全性、轮轴运用可靠性，获得极端条件下轮轨安全性特征；④研究轮轴弹性变形附加动力与轮轨强迫振动，揭示轮对弹性对轮轨安全性影响特征，确定高速轮对动平衡量合理限值；⑤研究高速旋转轮对轮轴压装截面应力分布特征，获得高速轮对压装力合理限值等。项目将拓展和丰富轮轨动力学理论研究范畴，为国内掌握高速轮对设计方法奠定理论基础，为研究高速轮对轴承振动和失效创造条件。

高速列车运行过程中轮对作旋转走行运动，这将引起轮轴弹性变形、车轮踏面磨耗、擦伤等缺陷。这些缺陷又将进一步影响轮轨系统安全性和结构可靠性。结合车辆动力学、转子动力学及结构强度等理论，在建立包含轮对弹性振动、旋转走行关系、齿轮啮合振动以及轴承振动的全弹性高速车辆-轨道系统动力学模型的基础上，项目开展了以下研究工作。.①研究了轮轴弹性变形和截面转角下的轮轨接触、蠕滑、走行和非均匀磨耗等动力行为，获得了高速轮对弹性变形对轮轨蠕滑和黏着影响规律。②研究了多种工况缺陷工况下轮轨安全性、轮轴运用可靠性，获得不同条件下轮轨安全性特征，提出了车轮踏面扁疤不同长度和宽度下列车安全运行速度域。③研究了轮轴弹性变形附加动力与轮轨强迫振动，揭示了轮对弹性对轮轨安全性影响特性。④研究了高速旋转轮对稳定性和轮轴压装截面应力分布特征，获得了轮轨约束和不同速度下轮轴压装应力变化规律。⑤分析了齿轮啮合载荷、安全性指标及部件振动特性，揭示了齿轮传动对高速车辆系统振动及安全性影响规律。⑥探究了轮对高速旋转走行下轴箱轴承的振动特性，获得了多种速度和激励条件下轴箱轴承载荷的变化规律。. 结果表明，高速动车组运行过程中车轴中部最大弹性变形量约为0.9mm，且车轴弹性变形对轮轨安全性有一定的影响。不同的车轮扁疤长度和宽度列车有不同的安全运行速度。在时变刚度和传动系统振动影响下，轮重减载率将比非传动工况下有一定程度增大，但对脱轨系数无影响。随机激扰影响下轴承载荷将发生变化，统计和提取这些载荷特征可为轴承设计提供帮助。项目拓展和丰富轮轨动力学理论研究范畴，为进一步揭示高速车辆系统振动本质和内在规律创造了条件，为保证我国高速列车运行安全性提供了帮助。. 项目共计发表期刊论文19篇，其中SCI和EI检索论文18篇、中文核心期刊论文1篇。培养博士和硕士研究生11名。