某大跨单层球面网壳结构的非线性屈曲研究

Research of nonlinear buckling for one large-span single-layer spherical latticed shell

为研究杆件稳定、初始几何缺陷、几何非线性、材料非线性对某单层球面网壳结构整体稳定性的影响,首先对结构进行线性屈曲分析得到屈曲模态和临界荷载,其次采用弧长法对结构进行非线性屈曲全过程分析,同时确定最不利初始几何缺陷分布模态,最后采用Newton-Raphson法对按此最不利缺陷分布的结构进行弹塑性屈曲全过程分析.计算表明:初始几何缺陷按最低阶屈曲模态分布的一致缺陷模态法可能不适用于大跨单层球面网壳结构的稳定性分析;荷载不对称分布对结构的稳定性更为不利;初始几何缺陷和材料非线性对结构稳定性的影响较大.

In order to study the stability of one single-layer spherical latticed shell with the influences of member buckling, geometric nonlinearity, initial geometric imperfection and material elastic-plasticity, the linear buckling analysis is firstly carried out to predict the buckling mode and critical load. Secondly, the nonlinear buckling behavior of the structure is investigated by using arc-length method and the most unfavorable initial geometric imperfection distribution mode of the struture is determined. Followed that, the elastic-plastic stability of the structure with initial imperfection is disseussed by adopting full Newton Raphson method. It shows that the consistent of mode imperfections method which takes the first order buckling mode as initial geometric imperfection may be less applicable to the stability anslysis of the large- span single-layer spherical latticed shell. The unsymmetrical loading distribution might be more dangerous. The initial geometric imperfection and the material elastic-plasticity might have significant effects on the stability of the structure.