| With the improvement of train running speed, which requires the vehicle bogie to develop in the direction of lightweight. The framework as a main load-bearing structure of the bogie, which is the most important object of bogie to lightweight development. The lightweight inevitably reduces the overall stiffness of the framework, and due to the decrease of the stiffness that caused natural frequency of the structure is reduced. At the same time, the range of the line excitation frequency become widening with the increase of vehicle speed,which leads to the line excitation frequency close to the natural frequency. The vibration of train body is aggravated and the destruction of the local structure is formed during the operation of train. Besides, because of high speed, the increasing dynamic-load stress of CRH3 bogie is so obvious that the fatigue strength problem of the bogie is more important.This paper takes the CRH3 Trailer bogie frame(non dynamic) as research object, and establishs the geometry entity model by referencing the two-dimensional engineering graphics of framework. The geometry entity model of framework is established by using the SolidWorks 3D modeling software. The mode is transformed into ANSYS analysis software,and the finite element model of framework is established by using workbench module. Firstly,according to the theory of the finite element modal analysis, modal parameters are calculated under the free modal, and the results including natural frequencies and modal vibration types.Based on the mode diagram of modal vibration, explaining the dynamic characteristics of framework,and judging the weak link prone to fatigue failure during the process of structure vibration by determining the extremum position of vibration curve curvature. The modal analysis results show that the weak link of the framework is mainly manifested in three areas during the process of vibration:The first,the connection area of the side beam and cross beam;The second,the cross section area where turning arm positioning seat is installed on the side of the beam;The third,the middle area of the cross beam. Then the framework is made analysis of static strength and fatigue strength respectively by using UIC615/515 and JISE standard. According to the standard of UIC615/515 loading experiment, in exceptional load conditions,the location of maximum stress is located in the connection area of lateral stop block and brake bracket,and the maximum stress value is 296.0MPa. In a simulated operating conditions, the key regional test points are evaluated about the fatigue strength, which based on the Goodman fatigue limit diagram. The results show that the most dangerous area is located in the connection area of turning arm positioning seat installed on the side of beam and the cover plate of beam; The danger area is located in the connection area of lateral stop block and brake bracket,as well as lateral stop block and the cross beam. According to theJISE loading test standard, the location of average maximum stress is located in the connection area of lateral stop block and brake bracket under braking load conditions,and the maximum value is 308.0MPa. In braking load conditions, based on the JIS fatigue limit diagram, the key regional test points are evaluated about the fatigue strength. The results show that the most dangerous area is located in the connection area of lateral stop block and brake bracket.The calculation results of frame modal analysis and strength analysis are integrated,and the characteristics of structure and technology are also considered, there are three main areas,which are prone to fatigue failure for CRH3 trailer bogie frame during the process of using as follow:The first,the connection area of the side beam and turning arm positioning seat;The second,the connection area of the side beam and cross beam;the third,the connection area lateral stop block and brake bracket. |
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