【作者】 李培；

【导师】 张乐乐；

【作者基本信息】 北京交通大学 ， 安全技术及工程， 2009， 硕士

【摘要】 我国高速铁路快速发展,对高速列车的承载安全性提出了新的要求。高速列车中重要的承载部件——转向架构架普遍采用焊接工艺,在构架焊接过程中形成的焊接残余应力和焊接缺陷势必会影响构架局部结构的承载状况。因此,分析研究焊接残余应力和焊接缺陷对构架承载能力的影响具有非常现实而重要的意义。本文利用有限元分析软件ANSYS,以国内某型高速列车转向架构架为研究对象,应用热机耦合有限元法进行了构架局部结构的焊接仿真,并分析了焊接残余应力场和焊接缺陷对构架承载能力的影响。最后设计并搭建了焊接缺陷超声波检测平台。首先,对转向架构架进行了有限元建模,并应用国际铁路联盟UIC515规范对构架整体进行了整体强度分析,得到了构架上平均应力和应力幅较大的局部结构。其次,建立了构架的局部结构有限元模型,应用热机耦合有限元法对局部结构进行了焊接仿真,得到了焊接残余应力场的分布趋势,并进一步分析了焊接残余应力场对构架承载能力的影响。应用弹塑性结构承载极限理论,计算了含有残余应力场的结构的承载极限,并画出了承载极限图。另外,建立了空洞类焊接缺陷的数学模型,以缺陷处的应力集中系数为评判标准,分析了不同形状和位置的空洞类焊接缺陷对构架承载能力的影响,绘制了影响曲线。最后,探讨了焊接缺陷的超声波检测平台的硬件设计,进行了硬件调试。更多还原

【Abstract】 The rapid development of high-speed railway in China calls for a new requirement of the safety of high-speed train. The bogie frame, which is welded together, is the most important component in a high-speed train. In the welding process, the welding residual stress and welding defects are formed, which will certainly affect the load-carrying capacity of welded bogie frame. Therefore, it is quite important to study how the welding residual stress and welding defects affect the load-carrying capacity of the welded bogie frame.Based on the finite element software ANSYS, a type of welded bogie frame is studied. Four local structures of the bogie frame have been welding simulated and analyzed based on the thermo-mechanical coupled finite element method. Furthermore, the affection of the welding residual stress and welding defects on the load-carrying capacity of welded bogie frame has also been analyzed. At last, an ultrasonic detection platform for welding defects are designed and debugged.Firstly, the finite element model of the welded bogie frame is set up, and then it is analyzed according to the UIC515 norms of International Union of Railways. Some local structures with larger average stress and stress amplitude of the bogie frame are obtained.Secondly, the finite element models of those local structures are set up and welding simulated based on the thermo-mechanical coupled finite element method to get the distribution trend of the welding residual stress on those local structures. According to the result of simulation, the cause of how welding residual stress affect the load-carrying capacity of welded bogie frame is studied. The ultimate bearing of the local structures with the welding residual stress is calculated based on the theory of ultimate bearing of elastic-plastic structural.Furthermore, the mathematical models of the empty type of weld defects are set up, the impact of different shapes and location of the welding defects, whose standard is the stress concentration factor, on the load-carrying capacity of welded bogie frame is then studied.In the end, the ultrasonic detection platform for welding defects is discussed and designed; also the hardware debugging is carried out.更多还原