The Research Of Development And Optimization Of Light-weight And High-strength Car Body Structure Concept

Automotive lightweight technology, which is difficult to break through, is the key to achieve energy-saving technology and critical point to develop new energy vehicles. The body structure of the current Electric Vehicles(EV) often follow the same form as conventional fuel vehicle body. So the mileage of EV is hard to meet the need of customer thanks to the high weight of battery. It makes many EV to become an unsuccessful products and also restricts the promotion of EV.In thesis, a kind of new design body structure will be researched to use in city car. This structure will have new forms of body structure, and the application of new lightweight materials. It is call Light-weight High-Strength Absorbable Framework(LHAF). In this design, a framework made by aluminum will withstand nearly most of the stress car suffered. It makes it possible for body structure to have outstanding strength, stiffness, modal and crash safety performance. The battery in EV will become the core facture in procedure of positive development.The difficulty of development of new body structure lies in the lack of reference and evaluation system. So it is necessary to build up the LHAF database, including LHAF material, multi-material body structure. A standard car is selected to gain the body data and performance of modal analysis and static characteristics. Basis on this database, the LHAF body can be designed. By means of topology optimization, the transmission path can be analyzed in the result of topology. A stepwise topology method is proposed to achieve the design-friendly topological results. According to this result, LHAF body structure can be designed with the use of modular modeling method. The whole structure is divided into 5 modules: front modules, door modules, back module, the floor module and ceiling. Each module will have multiple forms. Two concept body is selected. After the analysis of the static stiffness and dynamic performance and multi-collision simulation, Concept No.2 is considered to have higher level of performance. Finally, aluminum space frame structure filled with aluminum foam structure is designed. Compared to the non-foam form, the peak acceleration of aluminum foam structure has decreased by 46.3%.In this thesis, the concept of LHAF body structure is presented. A new kind of body is designed to meet the need of light-weight high-strength and energy-absorbing body. It will be an important reference for the development of EV body.