Finite Element Analysis And Optimization Of Bus Skeleton Of Middle Body Built With Aluminum

At present, lightweight design is an important method to lowering fuel consumption, energy conservation and emission reduction and improving characteristics of vehicle. Compared with steel body and aluminum body of vehicle, steel-aluminum body combined the strength and rigidity of body and the cost properly. Steel-aluminum body is the vehicle body which instead some structure by aluminum.This paper instead the material of body between B pillar and C pillar with aluminum based on steel body, and designed five aluminum alloy sections with different cross-sectional shape and connecting pieces, built the CAD model of city bus skeleton which middle body built with aluminum and finite element model. And then had mode analysis and statics analysis of city bus skeleton under four working condition with HyperWorks. According to statistics analysis result, this paper made some locality structure optimization at the place where there is stress concentration; and provided some advices to solve the problem that the deformation of city coach body large opening diagonal is a little big.The result of analysis and optimization showed that low order intrinsic frequency of steel-aluminum city coach body is among 7.084-20.334 Hz, avoid the range of common excitation frequency, and intrinsic mode of vibration has no mutation.The result of four operating condition show that the large opening diagonal deformation of front window under twit operating condition is the largest-13.255 mm. Some large opening deformations were upon 10 mm. The largest stress is 465.397 MPa, at location of abutment where air spring of rear axle. After locality structure optimization and size optimization, the biggest stress decreased 44.931 MPa at the location of stress concentration at the base of static strength analsis.