Conceptual Design And Performance Matching For Body Front Structure Of Electric Vehicle

At present,the production and sales of electric vehicles in China have ranked first in the world and China becomes No.1 in electric vehicle quantity.However,domestic automobile enterprises still use traditional concepts to design electric vehicle structures.Compared with foreign enterprises,China is still in a backward position in many aspects.So we need to continue to work hard in the field of new technologies.In all complex mechanical structures of the car,the front body structure of the front bumper and the front beam are the key components to ensure the safety of frontal impact.In this paper,it starts from the front structure conceptual design of the electric vehicles' body,then studies the impact of different cross-sectional shapes on the frontal impact safety of the car as the front bumper and the anti-collision beam to find the best shape.When the body front structure has been established,it will be optimized of the multi-objective optimization.Firstly,the material used in the front bumper and the front beam is aluminum 6061.The design space of the front bumper with oval,quadrilateral and octagonal sections is adopted.And the cross-sectional shape of the front bumper is obtained by topological optimization and size optimization.Then,a finite element model of automobile low speed collision was established to calculate.By comparing the energy absorption,the change of the pendulum's impact velocity and the collapse amount of the front bumper,the optimum cross shape is octagonal section.Secondly,a frontal impact model of a white-body bench test was established to compare the simulation with the test and verify the credibility of the model.The design space of the front beam with a regular octagon,a quadrangle and a circular section is adopted.Through topological optimization,the corresponding cavity cross-section shape is obtained.Contrasting the quadrangular section front beams without ribs and that with cross ribs,it is found that the cavity structure without ribs is more suitable as the front beam.Then the octagonal cross-section bumper is assembled by three front beams.By comparing results of high-speed frontal crash simulation and experimental verification,the best front structure is the combination of the octagonal front beam and octagonal front bumper.Thirdly,optimizing the proposed front structure by using multi-objective optimization.It results in energy absorption ratio increase of 2.72%,acceleration peak reduction of 7.91%,rigid wall reaction root means square reduction of 11.20%,front structure mass decrease of 8.15%.As a result,the overall safety of frontal impact has been effectively improved.