K6型单层球面网壳整体交互耦合屈曲行为

Global Interactive Buckling Behaviour of K6 Single-layer Spherical Reticulated Shells

摘要:

采用有限元数值模拟，基于K6型单层球面网壳的屈曲与后屈曲性态，提出整体屈曲的判别准则，并首次从变形特征角度分析两种整体屈曲模态交互耦合的发生机理及对屈曲承载力的削弱效应。研究结果表明，K6型单层球面网壳的稳定性易受整体交互耦合屈曲影响，且可导致屈曲极限承载力的显著削弱及不稳定后屈曲；其变形模式从屈曲阶段的最低阶整体屈曲模态主导，演化为初始后屈曲阶段的整体交互耦合屈曲模态主导，及最终的次低阶整体屈曲模态主导，是交互耦合屈曲产生的原因；缺陷幅值也会影响整体交互耦合屈曲对K6型单层球面网壳屈曲极限性能的主导作用。

关键词:空间结构;网壳结构;有限元模拟;耦合屈曲;非线性稳定

Abstract:

Using finite element modelling， this paper investigates the buckling and post-buckling behavior of K6 single-layer spherical reticulated shells. Based on the proposed criterion to distinguish global buckling modes， the mechanism and load-carrying capacity reduction of global two-modal interaction is revealed from the perspective of deformation. The results show that the stability of K6 single-layer spherical reticulated shells is vulnerable to global interactive buckling， which may lead to significant load-carrying capacity reduction and unstable post-buckling behavior because of the deformation transition from first global eigenmode dominance at the buckling stage to global interactive mode dominance and second global eigenmode dominance at the initial and final post-buckling stages respectively. Imperfection amplitudes can affect the dominance of global interactive buckling for the ultimate behavior.

Key words:spatial structures;reticulated shells;finite element modelling;interactive buckling;nonlinear stability