Research On Forward Conceptual Design And Lightweight Of Mini Electric Vehicle Body

With the increasingly prominent problems of environment and energy,countries around the world are committed to the development of new energy vehicles,and pure electric vehicles have become a key research target due to zero pollution and relatively mature technology.However,pure electric vehicles are faced with the difficulties of short cruising range and difficult charging.Lightweight body can reduce the weight of the car,which is one of the important ways to improve the cruising range of pure electric vehicles.The lightweight design of the body is actually a forward design of the whole vehicle that is performance-oriented.At present,most of China’s automobile manufacturers still use the traditional reverse design,which restricts the development of lightweight.Therefore,the research on the body’s positive development and lightweight technology is of great significance for improving China’s automobile research and development capabilities and accelerating China’s pace of becoming an automobile power.Conceptual body design is an important part of vehicle development,and this paper focuses on the thin-wall stiffness design method suitable for forward conceptual design of the body,and introduces the lightweight concept into the body conceptual design stage to optimize the main cross-section parameters of the body beam.Firstly,taking the miniature electric vehicle body as an example,starting from the overall layout of the body and the basic structural parameters,using the topology optimization method and comprehensively considering 5 typical working conditions to perform multi-objective topology optimization design for the lack of body structure information in the conceptual design stage,and determining the skeleton model of the car body beam,thereby extracting the simplified geometric model of the car body.Secondly,considering that the body beam is a thin-walled structure,combined with the warpage characteristics of the thin-walled structure,the mechanical model of an arbitrary closed single-cell cross-section beam is derived using the Vlasov beam theory,and the mechanical relationship between the 14 state vectors and 15 section properties of the thin-walled beam is established.Then,using the joint of the car body beam as the coupling node,the transfer matrix method is used to derive the stiffness chain model of the whole car body beam,and the car body stiffness analysis model including the properties of the main section is established.By comparing with theresults of finite element analysis and the calculation results of existing stiffness chain methods,the validity of the thin-walled stiffness analysis model proposed in this paper is verified.Finally,In order to further improve the weight reduction effect of the car body,two-layer optimization of the main body section is performed,with bending and torsional stiffness as performance constraints and multi-material cost as constraints.The results show that the weight reduction effect is obvious.The research in this paper takes into account the warpage of thin-walled beams and other factors to improve the accuracy of the body stiffness chain solution.At the same time,it proposes a body weight reduction method suitable for the conceptual design stage,which provides a reference for the body’s forward development and lightweight design.