| Automobile lightweight has become one of the most direct and effective measures to reduce energy consumption and emissions of electric vehicles and fuel vehicles.It is an important strategic layout to achieve " carbon peak and carbon neutrality." It is of great significance to the sustainable development of automobiles with light weight,high strength,safety,energy saving and environmental protection.In this paper,the body frame of Hongqi electric bus is taken as the model,and the aluminum alloy is taken as the lightweight material of the body.Starting from the structural design,the finite element optimization model of the body is established.The structural optimization is carried out through the simulation analysis of the modal and stiffness of the white body,and the key manufacturing technology is studied.The aluminum alloy body of the electric bus is developed to realize the lightweight goal of the aluminum alloy body.The main work is as follows :(1)Modeling analysis of electric vehicle body in white.Using geometric cleaning,meshing,material setting,connection simulation and other technical means,an accurate finite element model of body-in-white was established.The mass of the finite element body was determined to be 399.2 kg,and the total number of shell elements,body elements and beam elements was 621042,which laid the foundation for the subsequent dynamic and static performance analysis of body-in-white.(2)Dynamic and static performance analysis of electric vehicle body-in-white.The natural frequency and vibration mode of the white body are obtained by modal analysis.At the same time,the first-order bending mode and the first-order torsional mode frequency of the white body are compared to verify the potential optimization space and dynamic performance results of the white body.The finite element method is used to analyze the bending stiffness,torsional stiffness and hole deformation of the body,and the evaluation is carried out in combination with the structural characteristics of the white body.It is verified that the overall bending and torsional stiffness distribution of the white body is reasonable and the continuity is good.At the same time,the bending stiffness of the white body is10995 N / mm and the torsional stiffness is 26420 N ·m / deg,which provides a theoretical basis for the lightweight design of the white body.(3)Lightweight performance verification and manufacturing technology research of electric vehicle body-in-white structure.The body size optimization is carried out with the wall thickness of the main bearing structure which affects the performance of the white body as the design variable and the minimum body mass as the objective function.The dynamic and static performance of the optimized body-in-white is checked and compared.The overall weight reduction rate of the optimized body is 9.78 %,and the lightweight coefficient is reduced by 3.6 % compared with that before optimization,which verifies the lightweight effect of the body.The preparation technology of high-quality aluminum alloy profiles and the welding technology of aluminum alloy body were mastered,and the design and manufacture of all-aluminum body for electric buses were finally completed.This article breaks through the key technologies of lightweight aluminum alloy body development and achieves the goal of lightweight aluminum alloy body by establishing a finite element model of electric vehicle white body,analyzing the dynamic and static performance of the body,verifying the lightweight performance of the body structure,and tackling key manufacturing technologies of the body.It also develops the Hongqi electric bus body product and forms an innovative application demonstration. |
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