Strength Analysis And Modal Study On Bogie Frame Of High-speed EMU

As a carrier for high-speed railway transportation, EMU must keep good application status. As the key bearing structure of the bogie, the frame not only bears the body weight and load, but also transfers various loads in the running vehicle. High speed intensifies the vehicle vibration conditions, and it makes the working condition of the frame more severe. Therefore, in order to ensure the safety and reliability of the running vehicle, the frame must have sufficient strength and rigidity.This paper selected the welded frame of EMU as the research object. By using the finite element method, the strength and modal of the frame was analyzed. This paper mainly completed the following work.The domestic and foreign strength design and testing standards of frame were compared and analyzed. Based on the JIS E 4207 standard “Truck frames for railway rolling stock-General rules for design” and “the interim provisions of 200km/h and higher speed railway vehicle strength design and test”, the loads of the frame was calculated under various conditions.The establishment of 3D entity model is the basis of the structural strength analysis. According to the technical drawing of the frame, the entity model of the frame was established by using 3D modeling software SolidWorks. In the modeling process, the frame was simplified. The non-stress concentration region of the fillet, chamfer were suppressed. The components installed on the frame which had little effect on the analysis results were also simplified.The finite element model was established using the finite element analysis software ANSYS Workbench, including the mesh model and the constraint boundary conditions. Based on the calculated load conditions, the static strength analysis of the frame was completed. And the static strength of the frame was evaluated based on the Mises stress method. The static strength of the frame meets the requirements of stress under various loading conditions.According to the results of the static strength analysis of the frame, the stress of the stress concentration position was calculated. And the fatigue strength of the frame was checked using the Goodman fatigue limit diagram. The stress of the checked position doesn’t exceed the envelope contour of the fatigue limit. The bogie meets the requirements of fatigue strength.Using sub modeling technique, the mesh of the guide column of the air spring mounting base was refined. In accordance with the analysis of the extraordinary vertical load of the "Provisional Regulations", the strength analysis of the sub-model was conducted. The maximum stress of the sub model was 57.875 MPa. Compared with the overall model analysis, the use of sub-model technique greatly reduces the computation time and improves the accuracy of the result.Finally, in the ANSYS Workbench, the modal analysis of the frame was carried out. The inherent vibration characteristic of the frame was studied. The vibration frequency and mode was obtained. The lowest natural frequency of the frame is 39 Hz, much bigger than the excitation frequency. So the resonance phenomenon can be prevented.