变工况条件下机车轮对轴承动力学行为仿真与实验研究

Due to the influences of many factors, such as traction, braking, track irregularity and track geometry, the actual running speed and radial load of locomotive wheelset are constantly changing. As a result, the variable speed and load are usual to the roller bearing in wheelset. The sensor, acquisition and identification of dynamic behavior of wheelset roller bearing under these variable operating condition, and evolution law of dynamic performance and damage mechanism of roller bearing are major contents in dynamic study. In the project, a large number of experiments on locomotive bogie faults diagnosis test rig are carried out, for study the variation law of key dynamic performance in locomotive wheelset roller bearing under variable operating condition. The important raw experiment data also can be obtained. After an analysis of the effect of load, temperature and rotational speed on contact stiffness, contact damping and frictional factor, the roller bearing models with typical faults are built by using multi-body dynamics and finite element method. Numerical simulation method is used to study the variation law of key mechanical parameters, and to explore the damage mechanism which lead to worse of the dynamic performance of roller bearing. The research results of this project have important theoretical significance and practical application values in deepening the fault diagnosis technology and improve the fault diagnosis theory and maintenance strategy of wheelset roller bearings.

受牵引、制动、轨道激励及线路状况等因素的影响，机车轮对的实际运行速度和所受径向载荷都是不断变化的。因此，轮对轴承的变转速和变载荷工况是一种常态。在这种变工况条件下轮对轴承动力学行为的感知、采集和识别，以及其动力学性能的演化规律和损伤机理等都是动力学研究需要考虑的重点内容。本项目拟先通过机车走行部故障诊断实验台，研究变转速、变载荷等变工况条件下的机车轮对轴承关键动力学性能的变化规律，并获得第一手实验数据。在充分考虑接触刚度、接触阻尼和摩擦系数等受载荷、温度和转速的影响情况的基础上，采用多体动力学和有限元方法建立机车轮对轴承的典型故障模型，通过数值仿真研究关键力学参量的变化规律，探索复杂工况和运行状态下导致轮对轴承性能劣化的损伤产生机理和演化规律。本课题的研究成果对深化故障诊断技术、完善轮对轴承的故障诊断理论和维修策略具有重要的理论意义和实际应用价值。

本项目在执行期内，通过高速列车轴承综合实验台和中国标准动车组服役性能跟踪试验，研究变工况条件下的列车轮对轴承关键动力学性能的变化规律，并获得了宝贵的第一手实验数据。采用非线性理论和转子动力学有关方法建立了含故障的滚动轴承非线性模型，分析了轴承内圈转速和故障尺寸对系统运动状态的影响。在充分考虑接触刚度、接触阻尼和摩擦系数等受载荷、温度和转速的影响情况的基础上，采用多体动力学和有限元方法，建立了列车轮对轴承的典型故障刚柔耦合模型，研究了变工况条件下滚动轴承存在损伤时内/外圈滚道、滚子和保持架之间的动态碰撞过程，分析应力、应变和振动随损伤状态(尺寸、位置等)的变化规律，探索了复杂工况和运行状态下导致轮对轴承性能劣化的损伤产生机理和演化规律。分别以变转速工况下轴承的故障诊断和微弱故障的特征提取为研究对象，提出了基于RE-SES算法的变转速条件下轴承的故障诊断算法，以及基于自适应EEMD和滑动峰态解调的滚动轴承的故障诊断方法等。利用NI虚拟仪器平台开发列车轮对轴承故障诊断系统，并通过大量的试验数据验证了系统的有效性。这些研究成果对解决变工况条件下轴承的服役性能演化规律、深化滚动轴承故障诊断技术、提高高速列车运行安全提供了理论基础和技术支持。