The Optimization Design Of Carbon Fiber Reinforced Plastic Of Pure Electric Vehicle Body Structure

The development of Pure Electric Vehicles(PEV) is an important part of the automotive industry toward the intelligent, electrical, and lightweight direction transformation. Under the influence of the third industrial revolution, automobile industry will undergo a subversive and revolutionary change in the material selection, manufacturing methods, energy information and many other aspects. But for now, the development of PEV is still in the early stage, and the vehicle market is still occupied by the traditional fuel vehicles. In the near future, along with the development of technology, and changes in the environment, social demand for PEV will get bigger. Because of large difference in power systems and energy systems between PEV and traditional vehicles, new design requirements are required to be proposed for vehicle structures including for body structure forms. Researching optimization method for electric vehicle body structure in conceptual design phase is of great significance for improving the whole vehicle performance, and for shorting the design cycle.The research is mainly based on the performance of stiffness of vehicle body, using a new type of Carbon Fiber Reinforced Plastics(CFRP) to design the structure of non-load-type electric vehicle body. CFRP is an ideal material to make the body lightweight; For the PEV which use non- bearing body, due to the load withstood is small, lightweight material is easy to be used and the personalized design of the body is easy to be realized, thus it can better meet the needs of the community. In this thesis, the mechanical properties such as anisotropy of CFRP were analyzed in details, and a simplified vehicle-body wireframe model was established based on mature electric vehicle. What’s more, the positions and parameters of 18 main sections were defined; and the load on vehicle body transmitted from the frame was obtained by calculation. A method of vehicle-body stiffness chain was proposed by using transfer matrix method which accurately described the relationship between the properties and the stiffness of main section of composite electric vehicle body. Taking the parameter of composite material of plies as optimization variables, body stiffness and strength as the main constraint, the lightest body mass as the objective function and with genetic algorithm as the solver, in the end the section parameter of main body of composite electric vehicle which just meet strength requirements was obtained; At the end of the thesis, the accuracy of the composite stiffness chain model and the feasibility of carbon fiber composite materials in pure electric vehicle body structure design were verified by comparing with the stiffness of steel body.The research of this thesis provides valuable reference for the application and development of new materials in the automotive industry, and discusses new design ideas for the development of pure electric vehicle body.