Study On Parametric Modeling And Scheme Optimization Of Aluminum Alloy Car Body

The weight reduction and performance promotion of car body of railway vehicle are always the main objective in the design and manufacture,the optimization design of car body structure is a important measure.The weight can be reduced,ride comfort can be promoted and fatigue life can be improved by a structure optimization design.In this paper,a car body of EMU is chosen as research object,the parameterized geometry model of car body is established by using of APDL programming language,then the finite element model is established by using of Hyperme sh software,therefore a quasi parameterized finite element model is accomplished.Basing on the parameterized finite element model,the quick modification of section and door parameters of car body is implemented,then the multi-scheme modal calculation are performed,and the optimized global parameters and sizes of car body are achieved,the overall section shape are therefore ascertained.Then,the plate thicknesses are optimized for further promoting performance and reducing weight.The main contents of this paper include as follows.1.The parameterized geometry model of car body of a EMU is established by using of APDL programming language in ANS YS software;2.The parameterized geometry model of car body is imported into HyperMesh software,the mesh generation is accomplished,the finite element model is established and therefore the finite element model is quasi parameterized,and then the modals of the empty car body are calculated;3.Basing on the quasi parameterized finite element model,the section outline parameters of car body including the height,width,total thickness of underframe,total thickness of side wall and total thickness of roof are chosen as design variables,the modal frequencies of various car body are calculated,then the optimized scheme of car body having the highest lower order modal frequencies are ascertained;4.The position of end door and middle door,the height and width of middle door are chosen as the design variable,the multi-scheme optimization design of car body are accomplished for promoting the modal frequencies,then again a new car body having the optimum door parameters are achieved for further promoting the lower order modal frequencies;5.Basing on the new car body having the optimized section outline and door parameters,the plate thicknesses of underframe,side wall,roof and door are chosen as design variables,the weight reduction is chosen as objective while the first three modal frequencies are kept not decreasing or further increasing,the optimization designs are completed.The results show that the lower order modal frequencies of car body can be promoted by improving the section outline and door parameters,and the lower order modal frequencies can be further increased by a optimization design of plate thicknesses,furthermore the weight of car body are also reduced while the strength is kept not decreasing.