| In this paper, a multi-domain synthetical method is used to study rigid-flexible coupled dynamic response and wheelsets fatigue life of high speed trailer EMU CRH2. A load-time series which is used to study wheelset fatigue life is outputed as a data file based on the rigid-flexible dynamics simulation model in which wheelsets are considered as flexible body. At first, the wheelset model is established by Solidworks software and the finite element model is established by ANSYS software. The finite element analysis is used to check the fatigue sterngth of wheelset by obtaining the wheelset's stress distribution, and the modal analysis is used to extract the flexible infomation of wheelset. Secondly, two kinds of vehicle dynamics model are established by SIMPACK software, the one is rigid system dynamics model, and the other is rigid-flexible coupled system dynamics model in which wheelsets are considered as flexible body. The dynamics simulation results of two models are compared in three aspects, such as vehicle runing stationarity, security and dynamic response of wheelset. A load-time series is outputed as a data file, which is prepared for calculating wheelset's fatigue life. At last, based on fatigue strength theory and combined with finite element analysis method, the wheelset's fatigue life is studied by N-code software.The results show that, at first, through the finite element analysis, the maximum equivalent stress is 311.7Mpa which occurs under the condition of 0.3mm interference fit between wheel and axis, and the maximum equivalent stress is less than the materal elastic limit stress of wheelset's. That means the interference fit can satisfy the assemnlage requre. The fatigue strength of wheel can satisfy EN 13979-2003 criterion's demand when the wheel is running under the straight line, curve line and turnout. The six extended natural frequency of wheelset is zero, belong to rigid body vibration. The main vibration type of wheelset is the first order mode of bend vibration of axie when its running, and the main vibration frequencies are all less than 200 Hz. Secondly, the dynamics simulation proves that the flexibility of the wheelset has very small influence on the vehicle running stationality and security, but it has great influence on dynamic response of wheelset itself. The vertical vibration acceleration of flexible wheelset is two times greater than that of rigid one, and the lateral vibration acceleration of flexible wheelset is also greater obviously than that of the rigid wheetset. At last, the outputed load-time serises data file is used to do further study on wheelset fatigue life. The results are that the wheelset's fatigue life is 2.26×107 kilometers, the wheel's fatigue life is 2.29×10~7 kilometers, and the axie's fatigue life is 2.24×10~7 kilometers. |
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