轻型客车车身刚度灵敏度分析及优化

SENSITIVITY ANALYSIS AND OPTIMIZATION FOR LIGHT-BUS BODY STIFFNESS

建立某国产轻型客车车身刚度有限元分析模型 ,确定有限元模型的边界条件及分析载荷 ,并对有限元模型进行试验验证。利用ANSYS软件就该车的车身骨架及车架各部件对车身弯曲刚度和扭转刚度的灵敏度进行分析 ,根据灵敏度分析结果选择设计变量 ,以车身的总质量和车身构件的最大应力为状态变量 ,以车身弯曲刚度和车身扭转刚度为目标函数 。

Structure analysis of light bus body usually just lays particular stress on intensity index and the experimental result of structure intensity is the key index of equipment registration in China. But, the body's structure stiffness also should be one of the key indexes. And, when the body's structure is design under stiffness criterion, it can satisfy the intensity criterion very well at the same time. The body's stiffness includes flexural stiffness and torsional stiffness. The flexural stiffness can be described as the body's deflection, under the plumb load, and the torsional stiffness can be described as the body's torsion angel, under the torsion load. A FEM model for stiffness analysis of a light bus body, which is made in China, is established in this paper. The FEM model's boundary condition--the supporting simulation of leaf spring, and analysis load--how to distribution the load to the FEM model are discussed too. Then, the FEM model is validated by experimental result. Moreover, by identifying the design variable, state variable, and the objective function of the model, the parts' sensitivity of body's flexural stiffness and torsional stiffness, which are constitutive parts of body frame or chassis, are analyzed respectively, using ANSYS. Choosing design variable due to the sensitivity analysis result, using the body's gross mass and the maximum stress of the parts as the state variable, and using the body's flexural stiffness and torsional stiffness as the objective function, the body's flexural stiffness and torsional stiffness are optimized.