Lightweight Body Structure Of City Bus Based On Topology Optimization And Sensitivity Analysis

Bus transportation is an important tool for people to travel.The lightweight of bus can improve passenger capacity effectively,achieve energy-saving and emission reduction.The body skeleton is the main load-bearing structures of passenger car,so it's significantly important to research on its lightweight.On the basis of finite element method,with the modern optimization theory and optimization design method utilized,and by means of finite element software,the study of lightweight based on a bus body skeleton of a bus manufacturer has been made.Based on the 3D digital model,the bus suspension system and finite element model of the body skeleton have simulated as well as the four kinds of typical working condition.The four condition are horizontal bending,torsion limit,emergency braking and sharp turns working condition.Through low-order vibration of free modal based on bus body skeleton analyzing dynamic characteristics of skeleton.And the results showed parameters of strength on the skeleton,stiffness and low-order vibration.Taking first order bending,torsion frequency of the skeleton,bending and torsional flexibility as constraint conditions and the minimum volume as the objective function,to analysis topology optimization of it.That based on the results of topology optimization,selecting 371 groups of bars as design variables to have sensitivity analysis for the skeleton.According to the result of topology optimization and sensitivity analysis,combining the regulation of company for finalize the design product,lightweight of body skeleton has been put forward,which made skeleton quality reduced by 240 kg.Compared with original skeleton,the new skeleton performance of original torsional stiffness and modal vibration have been maintained,bending stiffness improved,and strength improved significantly.Achieving the goal of bus body skeleton lightweight.