| As socialism with Chinese characteristics enters a new era,the people's need for a better life is growing day by day.In order to meet the high requirements of the public for travel,highspeed railway,as the preferred mode of transportation for the public in recent years,has made great contributions to the public travel and regional economic development with its convenient service mode and efficient service quality.In order to make high-speed rail vehicles serve the people continuously and safely,it is necessary to study the fatigue of key load-bearing components of high-speed rail vehicles.Bogie,as the key bearing part of high-speed rail vehicles,supports the vehicle body,bears and transfers the alternating load between the vehicle body and wheelset,and is the key part of the smooth and safe operation of high-speed rail vehicles.Therefore,the bogie frame connecting the functions of the bogie components,as the bogie skeleton,directly bear the various loads from the outside.With the increasing speed of highspeed railway,the extreme value of the alternating load on bogie frame is increasing,and the fatigue damage is increasing.At present,bogie is mainly divided into welded frame and nonwelded frame,and welded frame,because it is processed by welding,the welding zone is easy to be the stress concentration area of the welded frame,which is easy to induce fatigue damage and cause safety accidents under the long-term action of load.Therefore,the research on the fatigue life of bogie welding frame can provide theoretical basis for the design and maintenance of bogie frame.This paper focuses on the fatigue life analysis of the bogie welding frame of a certain type of high-speed emu.It mainly analyzes the static strength,fatigue strength and the fatigue life of the weld zone of the bogie welding frame of a certain type of high-speed emu based on the UIC standard,and finally considers the impact of welding residual stress on the fatigue life.1.in this paper,the solid model of bogie frame of a certain type of high-speed emu is firstly established and simplified to obtain a reasonable simplified finite element model.The static strength of bogie frame is analyzed according to the international railway union code UIC615.2.according to the working conditions of bogie frame in service,the load time history of each bearing part of bogie frame under cyclic working conditions was obtained,and the load spectrum was compiled in the fatigue analysis software.The finite element results of stress fatigue life analysis of bogie frame under unit load are obtained by quasi-static method.The fatigue analysis process was completed in ANSYS and nCode Designlife.The stress fatigue life analysis of bogie frame based on nominal stress method was completed by using s-n curve of material and load spectrum under cyclic working conditions and Miner's rule.3.refine the weld structure of the welding area between the upper vertical plate and the left and right side plates of the side beam of the bogie frame and the riser area.The weld zone was characterized by quadrilateral element and set as a set.The results of stress analysis for fatigue life analysis of welds are obtained by quasi-static method in finite element software.The fatigue life of the weld joints on the side girder of bogie frame was analyzed by using the weld fatigue analysis module based on the s-n curve of the seam welding materials provided by the seam welding in cyclic working condition load spectrum and nCode DesignLife material library.4.considering the influence of welding residual stress on fatigue life,the residual stress generated by welding is considered into the fatigue life analysis of welding seams by means of modifying the average stress through static compensation.According to the residual stress values measured in the literature,the residual stress peaks of tensile and compressive stresses based on the measured values were given by the static compensation method,and the fatigue life was calculated in this case.Considering the influence of heat treatment on the fatigue life,after welding bogie frame are obtained by literature,with or without heat treatment after welding residual stress in the measured values of each area by static compensation value method to implement the two cases of different welding area of residual stress value,through analysis to get approved by or not the heat treatment after welding bogie frame under the condition of fatigue life. |
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