基于子模型的大型复合材料飞机结构屈曲稳定性数值分析及优化技术研究

Research of the buckling stability analysis and optimum design of a composite wing based on the submodel technique

随着计算机科学和有限元技术的发展,屈曲稳定性问题有限元数值求解技术已经比较成熟但是在大型复杂结构工程应用中还是由于计算量大、收敛困难而受到限制,特别是在需要反复迭代计算的优化过程中,更是受到该问题的困扰。针对某大型复合材料机翼结构的考虑稳定性约束条件的优化问题,提取其典型盒段进行分析技术验证,研究计算效率和精度对于单元尺寸的要求。取误差限为1%,位移计算模型单元尺寸要求为150mm,而屈曲临界载荷系数计算模型单元尺寸要求为10mm。采用150mm的单元尺寸建立全结构模型进行位移求解,将位移计算结果应用于采用单元尺寸10mm建立的危险部位子模型进行稳定性求解,完成某复合材料机翼结构打样阶段优化设计,结构总质量较初始设计减轻24%,在满足精度要求的同时,计算效率显著提高。

With the development of computer science and finite element method, the finite element solution to buckling stability has been researched much more and can quite work well. But it is still enslaved to the large and complex structures, because of the spending and convergence. In the process of iterative computation for optimum design, this disadvantage is especially severe. In the optimum design of one large composite wing subject to buckling stability constrant, the typical box structure of the wing is built to research the element size requirement of computation precision and efficiency. Here the error limit is set to 1%, and the model with element size of 150mm can be satisfaction to the displacement, but 10mm to buckling load factor. In this paper, the wing is meshed with the element size of 150mm to obtain the displacement solution, which is used to decide where the submodel with the element size of 10mm is built to gain the buckling solution. By this method, the optimum design of the wing is finished efficiently and accurately, and the structure weight is reduced about 24%.