复合材料叠层及加筋旋转壳稳定性有限元分析

本文用有限元法研究了复合材料旋转壳及其离散纵向加筋情况的稳定问题。在SABA族元素1]的基础上,把复合材料各向异性的弹性性质考虑进去,把纵向筋条处理成为空间梁,计入梁偏心的影响,由梁的基本弹性和几何刚度矩阵出发,经过一系列变换,推导出与SABA元素相协调的新的弹性和几何刚度矩阵,从而较为精确地得到了复合材料叠层及加筋的稳定性分析结果。算例与现有的一些解析解及实验结果吻合良好。

Stability Analysis of Laminated and Stiffened Composite Shells of Revolution by the Finite Element Method

On the laminated composite shells of revolution, Simitses et al. 3, 4]have done a great deal of research work, while on the stiffened ones, Wanget al. 5, 6, 7] have also done a series of research work. But up to now, tothe author's best knowledge, there have been no papers reported in the openliterature on the stability analysis of the laminated composite shells of revo-lution, both unstiffened and stiffened, by the finite element method. It is just the purpose of this paper to make use of the finite element tosolve the stability problems of the laminated composite shells of revolution,including the discretely stringer-stiffened ones. For laminated composite shellsof revolution, the anisotropic elastic property is brought into the elasticitymatrix of an axisymmetrical thin shell element, such as SABA element 1];for discretely longitudinally stiffened shells of revolution, the stiffener is dealtwith as a space beam-column. From the basic (elastic and geometric) stiffnessmatrix of the beam-column, a new (elastic and geometric)stiffness matrix com-patible with an axisymmetrical shell element can be derived by a series oftransformations with the eccentricity effect taken into account. Thus, thestrengthening effect of the discrete longitudinal stiffener can be calculatedmore accurately. Then linearized incremental iterative method can be used toobtain the critical buckling load 2]. Finally, three examples are presented in this paper. The results agree wellwith existing analytic solutions and experimental ones. It shows that the methodpresented in this paper is quite satisfactory.