单层柱面网壳失稳区域预测及稳定承载力优化

Prediction of instability regions and optimization of stability bearing capacity for single-layer cylindrical reticulated shells

网壳结构的极限承载力往往由其稳定性能所决定.从杆系结构在失稳前的受力状态分析出发,构建了以杆件的拉压刚度和杆件与节点切平面夹角乘积之和的网壳杆件构形刚度参数.通过对两个不同矢跨比柱面网壳的分析表明,考虑初始几何缺陷后,柱面网壳结构的失稳点发生在杆件构形刚度参数最小的区域;加强杆件构形刚度参数最小区域的杆件截面可以快速提高网壳的稳定承载力,且用钢量较为经济.所构建的柱面网壳杆件构形刚度参数以及衡量稳定加强效果的指标可以较好地预测失稳区域以及指导柱面网壳结构稳定承载力的优化设计.

The ultimate bearing capacity of reticulated shell structures is often determined by their stability behavior.In this paper,based on the analysis of stress state of bar structure before instability,the configuration stiffness parameters of members for reticulated shells are constructed by the sum of the product of tension and compression stiffness of members and angles between members and the tangent plane of the joint.Through the analysis of two cylindrical reticulated shells with different rise-to-span ratio,it is shown that the instability regions of cylindrical reticulated shell structures occur in the areas with the minimum configuration stiffness parameters of members after considering initial geometrical imperfections.Strengthening the member sections in the areas with the minimum configuration stiffness parameters of members can quickly improve the stability bearing capacity of the reticulated shell,and the steel consumption is more economical.The results show that the configuration stiffness parameters of members and the index which is used to evaluate the stability strengthening effect of cylindrical reticulated shell,can be used to predict unstable regions and guide optimal design of stability bearing capacity of cylindrical reticulated shell structures.