Car White Body Structure Modeling Studies And Mechanical Properties

The structure analysis of car body based on the FEM is the fundamental approach in the process of car body design-oriented. Also, the whole process of car body design becomes parallel in design and analysis. New characteristics and trends of car structure design come into being from modern analysis of car body structure. And they are significant in the design process.The phase of body-in-white concept design is important to assure performance in body-in-white structure design, of which the bugs is too difficult to be corrected in subsequent design. Consequently, during the design process, Computer Aided Engineering (CAE) is applied to analyze and evaluate the characteristics in real time, which makes the design more efficiency, more systematic and more standard.First, based on analysis of the geometrical sculpts of curve shape of car body, the thesis illustrates how to establish CAD model of car body structure and how to transfer the data among commercial software codes in details, from which FEM model is obtained. Second, the bend stiffness, torsion stiffness and modal of car body structure are analyzed. The sensitivity and optimization are performed in the research. Finally, given the characters of car body design, the car body development platform is constructed.One of main tasks in the thesis is to solve the connection between car body styling and structural design and to present the transformation from the geometrical sculpts of curve shape of car body to the analysis of the structural of body-in-white.Another task of the thesis is to research the generalized sensitivity adapted to large and complex system, such as the body-in-white. The sensitivity of car body structure to performance is calculated and the sensitive parts are obtained by comparison in detail. Then different parts contribution to car body is acquired, which provides the basis for design variables of optimization. The research in the thesis indicates that optimization variables calculated by this method can improve accuracy and efficiency of the results. So the whole design can be more efficient and practical.