基于灵敏度分析的汽车车架轻量化研究

摘要

The finite element model for an off-road vehicle frame is established, its stiffness and lower order modal frequencies are obtained by finite element method. The result provides reference for the frame lightweighting design. The rationality of the model is verified by the comparison of the modal frequencies obtained by numerical simulation test respectively. Based on sensitivity analysis, the optimization on the thickness of frame parts is conducted using an objective of minimizing the mass of frame with the constraints of meeting the requirements of bending stiffness, torsion stiffness and lower order modal frequencies. The results show that the total mass of the frame is reduced by 8.62%, at the same time the first order modal frequency is increased by 1.02 Hz, the bending stiffness and torsion stiffness are increased by 5.52% and O. 79% respectively.%以某越野车车架为例，建立车架有限元模型，采用有限元法求得车架弯曲刚度、扭转刚度和低阶模态频率，计算结果为下一步车架轻量化设计提供参考依据。并通过模态频率计算值和试验值进行比较，验证了该模型的合理性。基于灵敏度分析方法，以车架质量最小为目标函数，在保证车架弯曲刚度、扭转刚度和低阶模态频率不降低的前提下，优化车架零部件厚度。优化结果表明：车架的总质量下降8．62％，同时弯曲刚度提高5．52％，扭转刚度提高0．79％，1阶模态频率提高1．02Hz。