Finite Element Analysis And Lightweight Design Of An Electric Vehicle

After half a century of development,Chinese automotive industry has made remarkable achievements from scratch,but the ensuing environmental pollution and energy problems are also increasing.In response to many environmental and energy issues,electric vehicles are booming with the support of national policies,promoting the coordinated development of electric vehicles with lightweight technology is one of the future trends in automobile development.This article makes a lightweight design of an electric car body which has parametric optimization of the car body sheet metal parts under the premise of ensuring the vehicle performance,and checks the optimized car body performance.It is of great significance to improve the market competitiveness of this car.Focusing on the two topics of body finite element analysis and lightweight design,the main research contents of this article are as follows:Based on the three-dimensional body model provided by the enterprise,a high-precision finite element model of the automobile body is established in Hyper Mesh.Through vehicle body static strength,static stiffness and free-mode simulation that obtains the equivalent body stress Mises stress,bending stiffness and torsional stiffness values,as well as low-order natural frequencies and mode shapes.According to the verification analysis,the maximum equivalent stress value of strength under typical working conditions is lower than the allowable stress of the material.The bending stiffness and torsional stiffness of the vehicle body are greater than the target stiffness and the overall deformation of the vehicle body is good.The natural frequencies and mode shapes of the low-order modes of the vehicle body are reasonably distributed.The simulation shows that the body-in-white has a large space for light weight which provides a reference for the light-weight design of it.Based on the finite element simulation results and engineering practice experience 32 body sheet metal parts were selected.With the goal of minimizing the quality of sheet metal parts and constraining the stiffness of the vehicle body and low-order natural frequencies,the thickness of the sheet metal parts is optimized.After several iterative optimizations in Opti Struct,25 sheet metal parts were optimized to reduce the total weight by 7.38 kg and the body weight by 4.1%.Under the premise of ensuring performance and considering cost,the body weight reduction coefficient was optimized from 3.6 to 3.4,the body weight reduction level reached a good level,and the body weight reduction effect was obvious.At the same time,the weight of the body has also affected the overall performance.Through checking the performance of the entire vehicle before and after lightweighting,the change rate of the rigidity of the body is less than 5%,and the diagonal deformation of the body openings meets the value specified by the enterprise;The modal frequency and first-order bending modal frequency change rate is less than 3%;the Mises equivalent stress of the vehicle body under typical working conditions is lower than the yield strength of the material,and the safety factor in each working condition is greater than the enterprise standard;the front of the vehicle 100% overall energy absorption and deformation of the collision is good,and the safety meets the C-NCAP standard.