Body stiffness and deformation analysis based Structural Optimization Method

Improve vehicle fuel economy and reduce the cost of automobile production has become a modern car the general trend of development, domestic and international major car companies have been increasing emphasis on lightweight design. The structure of the car body stiffness analysis, automotive design engineers to analyze the results as a basis for optimal design of body structure. The whole structure is now Unibody cars with the structure, this structure to a large extent on the cars handling and stability to meet people, and the manufacturing process of the lightweight body design, and many other requirements. Unibody structure of the whole carries almost all the cars in use the load, including the bending and torsional loads and impact loads and so on. In the joint action of these loads, the stiffness of car body becomes extremely important. If less than the stiffness of car body, car in daily use, the deformation of car body will be greater, especially in columns, door frames, window frames and some key parts, a large deformation can cause poor vehicle sealing, door locks deformation, the interior off, and may even result in the door jam, window frames, broken glass, and so squeezed; this will directly affect the reliability of used cars, safety, NVH performance and fuel economy and other key performance indicators. Major domestic and foreign car companies of Car static stiffness of the structure calculation has been very seriously. The car body stiffness and deformation analysis of calculation and optimization of structural design of car body, and its main purpose is to ensure the body stiffness and deformation within reasonable limits under the premise of optimizing the body structure design. Just spent the surplus for the local body parts, structural improvements, a reasonable distribution of the car body stiffness; on the local stiffness of the weak part of the body to make reasonable and effective strengthening of the overall stiffness of the car body to the initial design requirements. In addition, the body structure optimization can improve the vibration characteristics of the body, and body weight can make the greatest extent possible to reduce further to solve the problems lightweight body. This subject is studied in the investigation of domestic and foreign automobiles stiffness based on the research, the establishment of an A0 finite element analysis model car, then the finite element analysis model was meshed, the model for the bending stiffness and torsional stiffness of the body analysis, finite element analysis model and body stiffness of the sensitivity calculation, calculation of sensitivity analysis based on the results of the stiffness, the stiffness of the sensitive components are the body, to master the different stiffness of the BIW components sensitivity to optimize the design variables that provided the basis for selection. Body Structure design, optimization results show that the study shows that the body design and development process, the sensitivity analysis for the body to provide a basis for structural modifications, is to enhance body rigidity and light weight body an effective way. 

Key words: white body; stiffness; sensitivity optimization