The Concept Development Of Micro-electric Vehicle And Research Of Multi-objective Optimal Design For The Lightweight Vehicle Door

Lightweight design is not only the key technique to energy conservation and emissions reduction for vehicle products, but also the bottleneck of automobile industry that difficult to break through. Using lightweight and energy absorbing structure to reduce body weight is the main way to vehicle lightening, and increasing the mileage of electric vehicles.The concept development for body structure is based on the 2015 Guangdong applied R&D special project- the key technical study on lightweight and energy absorbing body structure. Using modern CAS technique, body shape design is achieved. And taking the door as the main research object, the multi-objective optimal design is based on modal, stiffness and crashworthiness by applying lightweight and energy absorbing material, which is to discuss the feasibility of new materials and new structure.Based on the analysis of market positioning and the techno-economic vehicle lightening, the development concept of micro-electric vehicle is raised, with the confirmation of that the positioning is city incog and the technical feature is lightweight and energy absorbing. According to the above idea, a new kind of body structure for the concept vehicle is designed by using lightweight and energy absorbing materials aluminum alloy, PDCPD and foamed aluminum. It is divided into two parts, unitized body frame and integrative body panel.After the research and analysis of the modeling features of electric vehicle, the body styling of the concept vehicle is designed with 3D models by using CAS technique. With the design philosophy of sports style and the feature of Lingnan culture, satisfactory designs are acquired. The CNC hand-board model of selected scheme is completed to verify its space and third dimension.Taking the door as the research object, innovative design is carried out on the structure with PDCPD, aluminum alloy and foamed aluminum. Mechanical properties of materials are obtained after material tests. Then the door’s key performance is analyzed with FEM method, including modal, local stiffness and crashworthiness. Combining the analysis results of FEM, taking first-order modal frequency, total mass and maximum deformation during the door’s crash case as optimal objects, the stiffness as constraint conditions, the thickness of panels as design variables, the door’s multi-objective optimal mathematical model is created. Then the multi-objective optimization problem is solved by direct loop and genetic algorithm NSGA-Ⅱ. Popper lightweight plan is selected among the Pareto set. It might be satisfying result.To sum up, the lightweight design for door structure is not only achieved in this paper, but also the feasibility of structure that made of lightweight materials PDCPD, aluminum alloy and foamed aluminum can be verified. The structure and design method have significance on the lightweight design of other body components.