杆件失效工况下K6型球面网壳抗倒塌机理研究

STUDY ON THE COLLAPSE RESISTANT MECHANISM OF K6 SPHERICAL RETICULATED SHELLS UNDER MEMBER REMOVAL CONDITIONS

大跨度单层网壳具有冗余度低,敏感性高等缺点,地震作用时重要构件失效后结构的抗倒塌机理值得关注。基于ABAQUS软件,在验证后的有限元模型基础上,以矢跨比1/6的K6型单层球面网壳为对象,分析重要杆件失效工况下结构的抗震倒塌机理。结果表明有限元结果与试验结果总体吻合较好,分析模型可靠。K6网壳在地震作用下发生重要肋杆失效后的倒塌模式为,以失效肋杆为对称轴,与下端相连节点产生较大位移后,引起局部区域形成对称破坏,该破坏继续扩展最终导致整体结构完全坍塌。

Large-span single-layer reticulated shells have the disadvantages of low redundancy and high sensitivity,so the collapse-resistant mechanism of reticulated shells should be concerned after the failure of important member during earthquake.Based on ABAQUS software and the verified finite element model,the seismic collapse mechanism of a K6 single-layer spherical reticulated shell with rise-to-span ratio of 1/6 was analyzed.The results show that the finite element results are in good agreement with the experimental results,and the analysis model is reliable.The collapse mode of the K6 reticulated shell after the failure of the important radial member under the action of earthquake is as follows:take the failed ribbed rod as the axis of symmetry,and after a large displacement occurs between them and the connecting nodes at the lower end,symmetrical failure is formed in the local area which continues to expand and finally leads to the complete collapse of the whole structure.