Study Of New Concept Electric Vehicle Body Design Method Based On Topology Optimization

At present, electric vehicle is a hotspot in urban transportation development. While themotors become more and more powerful, latest battery capacity grows bigger, and energycontrol strategy to be more accurate, the challenge in front of us becomes how to make anefficient body in white so that it can save energy and high-efficiency in energy utilization.Based on this point, the paper was launched. According the development trend of electricvehicle, it becomes clear that the future electric car will have characters such as: supportedby its own independent chassis, be driven by wheel hub motors, controlled by wires, et al.The aim of this paper is to study and build the concept model of an individual chassis, andthe methods used including topology optimization, size optimization, etc. The maincontents are listed in the following:Firstly, after summarize topology optimization theory, and compare the linear andnonlinear topology optimization in details, different mathematic models were builtaccording to relevant working conditions. In order to make use of topology optimization innonlinear area such as crashworthiness optimization, the strain energy density method wasintroduced, therefore a total different mathematic model was built so that certain structurescan absorb energy in the utmost while protect the passengers in the car during accidents.Secondly, the finite element model was built according to recent researches and thereference model. Given the different stress and deformation of body in relevant workingconditions, the optimizations were conducted in every condition, and every optimizationhas its own aim and constraints. Under linear static condition, such as bending conditionand torsion condition, the aim is to minimize the compliance, while the constraintsincluding volume fraction and displacement of certain nodes. As to the nonlinear dynamiccondition, such as front impact and rear impact, the aim is to uniform the internal energydensity while the constraints including volume fraction and displacement.According to research results and decision-making theory, this paper presents amethod to make the weighting coefficient to be more accurate. Sort the former results basedon certain density value, so the material distribution results will reveal the importantbearing load frame. The chassis structure was built based on topology optimization results and taking into consideration of manufacturing process.Finally, the chassis shell structure was further optimized making use of multi-objectivemethod under common working conditions. Results show that the chassis frame behavesbetter under both working conditions after size optimization.