Lightweight Design Of Electric Vehicle Based On Side Impact Safety

With the continuous improvement of the global economic level,the automobile greatly improves the convenience of people’s transportation,at the same time,it also poses a huge challenge to the green ecological environment,oil energy demand and urban traffic construction.In this context,electric vehicles began to enter people’s attention,but due to the limitation of battery technology,the driving mileage problem has been an important reason that electric vehicles can not be accepted by most consumers.The research shows that under the same battery capacity,the greater the self weight of the electric vehicle,the shorter the driving mileage,so the self weight of the electric vehicle should be minimized.As the battery box of electric vehicle is generally installed in the middle of the floor,if there is a side impact accident,the battery box may be squeezed or even explode.Therefore,how to achieve the lightweight target of electric vehicle,and meet the safety of side collision personnel and battery safety is the main research goal of this paper.Firstly,the 3D model of electric vehicle was built in CATIA software and then imported into Hyper Mesh for pre-processing to build the finite element model of electric vehicle,and the model geometry cleaning,mesh division and mesh quality inspection results,material property definition,contact setting,etc.in the modeling process are discussed in depth.The finite element model of electric vehicle side impact is established in combination with C-NCAP test regulations 2018.Then,the intrusion volume and intrusion speed of five measuring points evenly distributed on the B-pillar in the process of side impact are taken as the evaluation indexes of the passenger safety of electric vehicle side impact,and the intrusion volume of eight measuring points on the sill beam of the side impact is taken as the evaluation indexes of the battery box safety.According to the simulation results,the optimization scheme of B-pillar is determined,that is,the continuous variable section panel is applied to the outer plate of B-pillar.At the same time,considering that the calculation time of vehicle side impact simulation is too long and the working efficiency is too low,the extraction of simplified model of vehicle side impact is completed.Finally,based on the orthogonal test design and response surface approximation model theory,through 16 simulation experiments,this paper established a response surface approximation model which takes the maximum intrusion amount of B-pillar,the intrusion speed and the maximum intrusion amount of battery box as the response.In order to obtain the optimal thickness distribution scheme of each section of B-pillar outer panel and realize the body lightweight.Taking the quality minimization as the objective,B-pillar intrusion,intrusion speed and battery box intrusion as the constraints,the mathematical model of optimal design was constructed and solved by genetic algorithm.According to the optimization results,the B-pillar outer plate was reset and collision simulation was carried out to verify the optimization results.It is found that the optimized electric vehicle meets the passenger safety and battery box safety at the same time,and achieves 11.3% weight reduction.