具有随机几何缺陷的大跨度单层球面网壳稳定性分析

STABILITY ANALYSIS OF LONG-SPANSINGLE-LAYER LATTICED DOMES WITH STOCHASTIC GEOMETRICALI MPERFECTIONS

网壳结构的稳定性是单层网壳结构设计中的关键问题。采用改进随机缺陷法对一大跨度K8型单层球面网壳进行随机缺陷稳定性分析,并研究非线性(几何非线性、材料非线性)、缺陷最大值等因素对单层网壳承载能力和临界荷载分布规律及其统计参数的影响。结果表明,单层球面网壳的临界荷载对曲面形状的安装偏差非常敏感,初始几何缺陷的影响非常大。缺陷最大值的增大将会使样本的最大值、最小值、均值及设计临界荷载显著下降,缺陷最大值对样本均方差的影响较复杂。材料非线性对大跨度单层球面网壳极限承载力的影响比较显著和复杂,对同一样本的影响有规律可循,但在不同样本之间没有必然的联系,在单层网壳结构设计中进行弹塑性稳定性分析是非常必要的。

The stability is the key problem in the design of single-layer latticed domes. An advanced stochastic imperfections method is used to research a long-span K8 single-layer latticed dome. The effect of nonlinearities （geometrical and material）and the maximum of the geometrical imperfection is studied to bearing capacity of single- layer latticed dome and the distribution of the critical load and its statistical parameters. Results indicate that the single-layer latticed dome is sensitive to the initial deviations of the surface shape. The increase of the maximum of the initial imperfection make the maximum, minimum, mean and design critical load of the samples reduce greatly, Material nonlinearities have a significant and complex influence on the dome. The elastic-plastic stability analysis is necessary in the design of single-layer latticed domes.