单层倒悬链型叉筒网壳静力与稳定性研究

针对以倒悬链线作为交叉柱面准线的单层倒悬链型叉筒网壳,对其常见网格形式结构的静力与稳定性进行比较,得到了结构最佳网格形式.在此基础上,将单层倒悬链型叉筒网壳与圆弧型叉筒网壳进行了静力性能与稳定承载力对比,研究了倒悬链型叉筒网壳的稳定性,包括屈曲模态及杆件截面尺寸、结构几何缺陷、荷载不对称分布与支座约束形式等对结构极限承载力的影响.结果表明,单层倒悬链型叉筒网壳三角形网格形式结构性能最佳;该结构相比圆弧型叉筒网壳具有明显的优越性;初始缺陷对结构稳定性影响较为显著,计算时应考虑1/300跨度的初始缺陷峰值;结构对不对称荷载作用较为敏感;矢跨比为0.50时,网壳的稳定性最好,为最优矢跨比.

Research on Static Properties and Stability of Single-layer Intersected Inverted Catenary Cylindrical Reticulated Shell

For the single-layer intersected inverted catenary cylindrical reticulated shell, the static properties and stability of the structures with different types of grid were studied and compared, and then the optimal grid form was obtained. The static properties and stability of the single layer intersected inverted catenary cylindrical reticulated shell were compared with those of the intersected circular cylindrical reticulated shell. Moreover, the stability of the former was studied comprehensively, including the buckling modes and the effect of various parameters such as the member sectional area, initial geometric imperfection, asymmetric load distribution, and support conditions on the ultimate load-carrying capacity. The results show that the structural performance of the single-layer intersected inverted catenary cylindrical reticulated shell with triangular grids is markedly superior to the circular one. Because, this kind of reticulated shell is sensitive to initial geometric imperfection, 1/300 of the structural span should be considered as the initial geometric imperfection value in the calculation of the ultimate load-carrying capacity. Additionally, the reticulated shell is also quite sensitive to the asymmetric load distribution, and the optimal value of rise-span ratio is 0.50 for shell stability.