高速动车组车轮疲劳裂纹研究

发布时间：2018-03-20 18:10

本文选题：轴重　切入点：横移量　出处：《太原理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：近年来随着我国高铁事业的飞速发展,极大地带动了国民经济的增长。京沪高铁与京广高铁的相继开通,大大加强了京津冀经济圈与长三角、珠三角经济圈的联系,促进了生产要素的快速流通,预计到2020年,“四纵四横”铁路规划网络会全面贯通,这将会带动东部、中部、西部地区的经济发展。并且随着“一带一路”战略的实施,我国的高铁技术将会走出国门,角逐世界市场。高速铁路与其他交通运输方式相比,具有以下优点:舒适快捷、安全平稳、节能环保、载运量大,同时高铁运输的整套设施可以带动我国装备制造业的向前发展。如今,动车组的实际速度可达到250~380km/h,运行一段时间后在车轮踏面和钢轨上就会看到大量的疲劳裂纹,这些裂纹贯通后又会形成许多点蚀凹坑。以及由于磨耗造成车轮踏面轮廓变形,即车轮失圆,上述的失效损伤都会恶化轮轨接触状态,并且引起冲击载荷,这时车轮需要进厂返修或更换钢轨,通过旋修工艺或打磨技术恢复轮轨的使用性能。调研发现:车轮表面比较光滑的部分,疲劳裂纹往往很少;表面粗糙的部分,疲劳裂纹很多。这说明轮轨间的疲劳与磨耗存在一定的竞争关系,一定程度上正是磨耗作用将部分疲劳裂纹磨去,抑制了裂纹的进一步扩展。因此在一定运行里程范围内,研究轮轨接触疲劳与磨耗的竞争关系,对于正确维护保养车轮与钢轨具有重要的现实意义。车轮踏面上的接触疲劳形成机理十分复杂,涉及到许多交叉的学科,至今对此类破坏现象形成的原因还在探索。本文在广泛借鉴国内外轮轨滚动接触疲劳损伤问题研究的基础上,首先模拟仿真轮轨接触在不同轴重、横移量、冲角、轨底坡下的应力应变状态,并找出对轮轨接触状态影响最大的因素,为后文进一步分析接触疲劳打下基础。其次对车轮踏面上人造裂纹的演化进行了定性分析,重点考察弯道半径、运行里程、冲击载荷对车轮踏面上疲劳裂纹的影响。实验操作为将车轮试样安装在实验台架上,对照现场采集到的运动状态信号,通过实验台架上的液压驱动器施加给车轮,促使人造裂纹演化。在实验后期,利用扫描电子显微镜、能谱分析仪、超声波探测仪、踏面轮廓测试仪等设备对车轮试样上的人造裂纹进行测试分析。结果表明:运行里程和接触状态对磨耗和疲劳都有很大影响,并且由于磨耗的存在,在实验里程范围内,车轮踏面上人造裂纹的最终演化深度小于其原始深度,因此可以得出车轮在运行20~30万公里后再进厂返修是可行的。
[Abstract]:In recent years, with the rapid development of high speed railway in China, greatly boosted the growth of the national economy. The Beijing-Shanghai high-speed railway and Beijing Guangzhou high-speed rail have opened, greatly strengthened the Beijing Tianjin Hebei economic circle and the Yangtze River Delta, Pearl River Delta economic circle, promoting the rapid flow of production factors, is expected to 2020, the "four vertical and four horizontal" the railway network planning will be fully opened to traffic, which will drive the eastern, central and western region's economic development. And with the implementation of the "The Belt and Road" strategy, high-speed rail technology in China will go abroad, for the world market. High speed railway compared with other means of transportation, has the following advantages: comfortable and fast, safe and stable. Energy saving and environmental protection, carrying a large amount, while the entire facility of high-speed rail transport can drive forward the development of the manufacturing industry of China's equipment. Now, the actual speed of the EMU can reach 250~380km/h, after a period of time running in Wheel tread and rail will see lots of fatigue crack, the crack will form many corrosion pits after. As well as wear caused by wheel tread contour deformation, namely the wheel out of roundness, the damage failure will cause deterioration of the wheel / rail contact state, and impact load, when the wheels need to repair or replace the rail into the factory the use of performance, by rotating the repair process or polishing technology. The research found that the recovery of rail wheel slippery surface, fatigue crack often; rough surface, fatigue crack a lot. This shows that there is a competition between fatigue and wear of wheel rail, to a certain extent it is part of the fatigue crack will wear off and inhibit further crack extension. Therefore in the running mileage range, competition between the study of wheel rail contact fatigue and wear, for the proper maintenance of wheels Has the important practical significance. The wheel and rail contact fatigue on the surface of the mechanism is very complex, involving many cross disciplines, so far the cause of such damage phenomenon is still exploring. In this paper, drawing on a wide range of basic research on rolling contact fatigue damage problem at home and abroad on the rail, the first contact simulation under different axle load, lateral displacement, impact angle, rail base slope under the state of stress and strain, and find out the influence factors on the contact state, for the further analysis to lay the foundation of contact fatigue. Secondly, a qualitative analysis of the surface crack of the artificial evolution wheel, focusing on the radius of the bend, running mileage, impact load on the surface fatigue crack effect of wheel tread. The experimental operation for the wheel mounted on the specimen on the test bench, the control state of motion signals collected at the scene, the hydraulic test bench. The actuator applied to the wheel, the artificial crack evolution. In the end of the experiment, by using scanning electron microscopy, energy spectrum analyzer, ultrasonic detector, tread profile tester and other equipment to test and analyze samples of artificial flaws. The results show that the running mileage and the contact conditions have a great influence on wear and fatigue, and because wear, in the mileage range, the final depth of surface crack evolution of artificial wheel less than its original depth, so it is feasible in wheel running 20~30 million kilometers after the factory repair.

【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U266

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