Structral Research Of Car Body-in-white Based On Finite Element Analysis And Testing Analysis

CAE technology, representatively FEA method, plays a more and more important role in the design of modern car products along with the development of computer technology and numerical calculation theory. It almost covers the most field of car design work. The full-bearing car body has been widely used in modern cars, which bears the whole loads from the other parts of car structure. It meets the demands of lightweight and energy saving, but also has high requirements of mechanical capabilities, both statically and dynamically, like stiffness and modal capabilities. Adopting the FEA technology to investigate the mechanical performance of the car body is prevailing in modern design of car body, which catches people's attention more and more and has great achievements in the domain domestically and oversea. Based on the investigation of the related domestic and overseas research in this field, the finite element model of a car body-in-white is established, static stiffness and modal analysis were carried on. Accordingly the static stiffness and modal testing had been finished. Results comparison between the testing and analysis revealed the structral capabilites and verified the finite model's correctness. The merits and demerits of the mechanical performance were pointed out, which provide consults for structure optimization design. The structure optimization design is also a part of this paper. The literature and informatin about this theme are summarized, the modification of FEA model and structre optimization are put forward, which are based on the gradient optimization and act well. The parametric model of the floor is established, The thickness/frequency gradient optimization is complished, which builds a firm foudation for the whole body optimization.During this research, some summarization is carried on in allusion to the problems and difficulties, such as the simulation of weldspots in the FEA model, definition of the boundary condition, selection of equation slovers in the stiffness and modal analysis; processing of the testing data. In conclusion, this paper did a overall theoretic and experimental research of the car body-in-white structure, which shows a great consistency and verfies the correctness of those ways and means. It provides a valuable consult and guidance for the further optimization of the whole body.