【作者】 李志华；

【导师】 任尊松；

【作者基本信息】 北京交通大学 ， 车辆工程， 2008， 硕士

【摘要】 车钩钩舌是货物列车中最重要的承载件之一,它直接关系着列车的运行安全和可靠性。随着我国铁路货运的重载化要求的不断提高,对车钩也提出了更高的要求。目前,大秦线重载列车的钩舌大量出现疲劳裂纹,其寿命远达不到设计的要求。因此,有必要对钩舌的疲劳可靠性进行研究,为提高钩舌的疲劳寿命提供依据。本文以我国大秦线上使用的国产16、17号车钩和美国产16、17号车钩为对象,分析了其可靠性,研究了二者的差异。本文主要作了以下四个方面的工作:1、建立小子样升降法数值仿真模型并进行大量模拟试验,为试验和准确处理数据提供依据。传统配对法求得的方差偏小,对计算结果影响较大。本文在数值模拟试验和已有数据的基础上,得出了关于小子样升降法应力级差、应力级数以及方差数据处理的一些结论。2、用MTS试验机以及GPL-100高频疲劳试验机,测试了国产材料和美国材料的性能参数;结合模拟试验结论采用成组法与升降法测试了两种材料的p-S-N曲线。3、通过考虑形状因素、尺寸效应和表面系数的影响,由材料的p-S-N曲线推导钩舌的p-S-N曲线。并且以尺寸效应为研究重点,分析总结了计算尺寸效应的各种方法。根据钩舌的受力状况,主要以有限元计算为基础,研究了尺寸效应的统计因素。4、建立钩舌有限元模型,分析钩舌的受力与约束,用ANSYS进行加载计算。根据车钩载荷谱和试验所得的基本疲劳性能数据,计算了国产钩舌和美国钩舌的可靠性寿命。美国钩舌的疲劳寿命高于国产钩舌。本文的研究结果将为我国重载列车钩舌的设计与应用提供技术保证与支持;本文的一些研究方法为同类型问题的研究提供参考。更多还原

【Abstract】 Coupler knuckle is one of the most importent bearing weight parts of heavy haul train. Coupler knuckle is importent to the safety of the railway transport and the problem of coupler knuckle cracks has been serious with the development of railway transport.It is necessary to study the reliability of coupler knuckle’s fatigue lifetime as fatigue cracks is more likely to appear on the coupler guard arm area. The object researched in this paper are the types of no.16 and no.17 coupler knuckles,which are used universally on heavy-load wagon of china.Two kinds of that coupler knuckles,the Chinese coupler knuckle and the American coupler knuckle, were studied and the difference has been find.The contents of this paper can be summarized as follows:1. Simulation model of small subsample fluctuation method is built and many tests have been carried out to service for the test and data processing. The finally calculation results will be very different as the dual small subsample fluctuation method gives a smaller variation.In this part some useful conclusions about test interval, the number of staircases of small subsample fluctuation method and the variation estimatent have been caried out based on numerical simulation and some test date.2. The Chineae and American material properties have been tested by MTS and GPL-200 high frequency fatigue testing machine.Also combined with the conclusions obtained by numerical simulation ,fatigue limits and p-S-N curves have been tested using the group method and up-down method.3. The coupler knuckle’s p-S-N curves have been derived by deduction from the material’s curves.Geometry effect,size effect and surface effect are considered in this process.the focus of this discussion is size effect. Methods of calculate size effect have been summarized in this part.according to the coupler guard arm area’s stress,size effect has been calculated mostly by the Statistics factors based on the resuts of the finite element analysis.4. Finite element analysis of the coupler knuckle is proposed.Finite element model of the coupler knuckle is built according to its entity, then is calculated by ANSYS based on its loads and constraints.Reliability analysis of fatigue lifetime of coupler guard arm area is proposed. It can program composition for caculating the reliability life of the coupler knuckle with the load spectrum date.the dispersion of coupler knuckle’s fatigue strength can be simulated with the Monte-Carlo method. As the fatigue lifetime of American coupler knuckle is higher than the Chinese coupler knuckle,the main difference is the slope of the p-S-N curves.The research results of this paper can provide technical guarantee and support for the design and application of coupler knuckle of Chinese heavy haul train.Some research methods in this paper also can be used in the research of similar type problems.更多还原