Development Of Skeleton Structure For The Frame/Body Construction Of A Mini Electric Vehicle

At present,the world automotive industry is pushing new energy vehicles,forming a new trend of industrial development.With the target of research on electric vehicle,China is increasing the research and development of related technologies continually.Endurance is the key performance index to restrict the performance of electric vehicles,the battery technology and the lightweight level of the body are the two main factors affecting the endurance.It is of great significance to improve the research and development level and endurance performance of electric vehicle in China by adopting the body design mode and forward development technology which are suitable for the market requirements,structural characteristics,performance requirements of electric vehicle.Based on the judgement of the development trend of Modular,platform electric vehicle body structure,in this paper,the light weight design is carried out for the body and frame structure of a kind of mini electric vehicle which adopts a non-load-bearing type body.In order to fully explore the load capacity and improve the lightweight level of body,the whole structure of vehicle with body chassis frame is decomposed into body and frame,and the concept of vehicle body bearing is defined.In this paper,the connection form and force transfer between body and frame are studied,and the function relationship between body bearing capacity and the force of each connection node is deduced,then,the body bearing capacity is introduced into the process of forward conceptual design of body and frame structure as an optimization variable.Furthermore,the calculation model of the forward design stiffness chain of the vehicle body including the bearing capacity of the body and the cross-section parameters of the structural beam element is established.The minimum mass of the whole structure of vehicle with body chassis frame is taken as the design goal,and the optimized structural parameters of the body,frame and the optimum load ratio between the vehicle body and frame is obtained by using the genetic algorithm.Which realizes the comprehensive optimal distribution of the vehicle material.And the rationality of the optimization result is verified by using the finite element analysis method.In this paper,some problems in lightweight design of steel and aluminum integrated frame are further studied.Based on the principle of equal stiffness,somebeam elements in the whole steel frame are replaced with aluminum alloy materials,and discussing the flow of conceptual optimization design of frame of steel and aluminum integrated structure from three aspects: determination of replacement position,analysis of lightweight characteristics of rectangular aluminum alloy thin-walled beam element and selection of optimization method,which has been proved reasonable,finally,pointing out the significance of the research on the connection and assembly process of steel-aluminum and aluminium-aluminum in conceptual design stage.