| In recent years,rail vehicles have developed rapidly.Bogie as one of the core technologies of rail vehicles,how to guarantee the structural reliability of Bogies and the safety of vehicle operation is an important topic of rail vehicles.In order to reduce the self weight of the bogie frame structure of railway vehicles in China,the steel welding structure is generally adopted,due to the introduction of various stress concentration in complex welded joints,the fatigue strength of the bogie is reduced,which makes the bearing condition of the bogie worse.It is of great engineering significance for improving the welding process design of Bogies and ensuring the reliability of the welding frame if we can study the stress characteristics of the welds in each area of the frame and get a reliable stress concentration factor.In this paper,the analysis and summary of the large stress parts of each type of steering frame are carried out by combining the data of test and test fatigue test data and test experience accumulated for many years in the laboratory of structural strength testing.Taking the bogie frame of Beijing Metro Line 4 as the research object,load analysis,static loading test and stress concentration test are carried out.The main research work is as follows:(1)In the light of the large amount of data on the dynamic stress test and static strength test of the subway and high speed rail EMU,the large stress parts of various types of structures are summarized in the subregion,and the specific position and direction of the stress measurement point of the key part of the key fatigue control part are clearly constructed,which provides the corresponding reference value for the dynamic stress test and the static strength test in the future;(2)Classify the load types of bogie frame and calculate the load of simulation operation according to the design standard of EN13749 bogie,carry out static loading test of frame,and the load response of the key fatigue control part is obtained by arranging the force sensor.The stress concentration factor of each welding structure is calculated and analyzed,and the stress concentration factor is obtained respectively;(3)Based on the measurement of welded structure size,the modeling method of welding structure using finite element simulation is established.With the help of ANSYS finite element analysis platform,the stress values of the welded structure of the frame are calculated.With the help of the Matlab scientific numerical computing platform,the specific position of the nominal stress in the simulation modeling structure is determined by the spatial surface interpolation method,thus the fatigue strength evaluation method of the simulation clockwise on the weld position of the welded frame is formed.The research in this paper can be used to improve the test criteria for the steering frame.It is of great significance for the design of the new frame and the reliability improvement of the insufficient fatigue strength of the structure of the welded structure,and it also provides data base support for evaluating the fatigue life of welded structural parts,enhancing the structural reliability of rail vehicles,and preventing the occurrence of safety accidents. |
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