Fatigue Analysis Of Aluminum Welding Body Of High-speed Train

With the great development of rail transportation technology in China,in recent years,various models of the EMU continuously rolled off the production line,through the vast majority of aluminum profile is used for passenger car body are formed a preliminary machining after welding the weld car body,make body of the aluminium alloy profiles for hollow extrusion forming,has high strength,light quality,excellent mechanical properties,easy processing and car body compared with the traditional made of carbon steel body with less number of weld,light weight,good air tightness and the advantages of the simplified process.But even so,the fatigue life assessment of welded joints has always been a difficult problem,and the corresponding agencies are constantly exploring appropriate assessment methods.Based on this,this paper will focus on the following contents:The difference between fatigue of welded joint and metal fatigue is summarized.By comparing several systems for evaluating the fatigue life of welding,it is found that the actual welded joint type is difficult to fit the existing joint type in relevant standards under the nominal stress method system.The equivalent structural stress method can realize the insensitivity of the stress to the grid and overcome the disadvantages of the nominal stress method.In this paper,the finite element model of the head car body of a certain type of emu is established,boundary conditions and working conditions are set as required,the performance of the car body under 10 static strength working conditions is investigated,the free mode of the car body is calculated,and the structural characteristics of the car body are analyzed as a whole based on the results of the two parts,so as to provide support for the selection of subsequent welding seams.With reference to the calculation results of static strength,free mode and fatigue static strength,10 evaluation welds were selected on the vehicle body.First,the fatigue life of 10 welds was evaluated by the master S-N curve method,and the corresponding conclusions were obtained by comparing the results under various working conditions.Then ANSYS and FE-WELD were combined to calculate the residual fatigue life of the weld based on the specific initial crack,and the general rule was obtained.Finally,the IIW standard was used to evaluate the fatigue life of 10 welds again,and the results obtained under the two evaluation systems were compared horizontally to compare the differences between them,and the corresponding conclusions were given.