| Along with our country’s economic and cultural development level,urbanization faster and faster,with rail transit industry has made great development,the high-speed railway in the railway traffic planning and the proportion of larger and larger.The mileage of China’s highspeed railways that have been put into operation has come from behind to rank among the top in the world.At the same time,the operation safety of EMU has gradually become the new focus of people’s attention.With the design of rail vehicles being lightweight and running at high speed,more and more attention has been paid to the load condition of the train body.By using advanced analysis methods,it can quickly and accurately analyze and improve the relatively dangerous stress position,which is of great significance to ensure the safe operation of the train.In this paper,the body of the head car of a certain type of EMU is taken as the research object.Through careful analysis of its structural drawings,a three-dimensional model is established,and its static strength,stiffness and modal simulation analysis are carried out.Based on the relevant standards,it is judged that all of them meet the standard requirements,and it is found that the crack location is the area with large stress;According to the site operation has been the location of the fault structure improvement,and then check that the safety factor of the location has been improved,and finally lightweight optimization design of the car body,the main work is as follows:(1)The simplified geometric model of car body is established by section equivalent method in software,and it is discretized into finite element model by Hyper Mesh;(2)According to EN12663-1-2010 and other standards,the load type and size of the car body strength analysis are calculated,and 16 kinds of car body static strength analysis conditions are obtained.According to the design condition combination,the strength and stiffness of the car body are analyzed by using the finite element analysis software.The strength analysis is based on the fourth strength theory,and the results meet the standard requirements.The analysis results show that the stress value at the fault location is larger,The reference standard of stiffness analysis is larger than the corresponding value,which meets the standard requirements;(3)The first twelve order free modal analysis was carried out on the car body under the two states of empty car body and ready car body.According to the modal analysis results and related data,the natural frequency of the first order bending of the car body in the empty car body was greater than 14 Hz,and the natural frequency of the first order bending of the car body in the ready car body was greater than 10 Hz,which met the standard requirements.(4)According to the failure of the car body of this type of train,combined with the strength analysis,the reasons are analyzed,and the reinforcement measures for structural improvement are made.Then,the strength of typical working conditions is checked,and the results show that the measures are effective,and the safety factor of the fault part is improved;Taking the thickness of the car body as the design variable,the stiffness displacement and the stress at the fault location with large stress as the constraint conditions,the lightweight optimization design of the car body is completed,and the overall weight of the car body is reduced by 7.96%,so as to achieve the purpose of lightweight.Finally,the static strength,fatigue strength check and modal analysis of the improved car body are carried out,and it is concluded that the design standard is met,and the lightweight design is reasonable. |
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