K6型单层球面木网壳稳定承载力非线性分析

针对4组不同节点构造、矢跨比的木结构网壳试验模型，采用ANSYS软件中的Beam189非线性梁单元模拟连接节点的半刚性特征，开展基于多段梁模型的网壳承载力全过程非线性有限元分析。通过对比有限元与试验结果在荷载 位移全过程曲线、破坏模式以及极限承载力等方面的吻合度，判断多段梁方法在木结构网壳稳定性分析上的可行性。研究发现：多段梁方法与试验结果较吻合，多段梁分析方法可有效揭示木网壳的破坏机理；矢跨比是影响单层木网壳破坏形式的主要因素，大矢跨比易出现强度破坏，小矢跨比易出现稳定破坏，节点刚度对小矢跨比模型的影响程度更加明显；弹塑性分析时，木结构网壳的极限承载力建议按弹性多段梁有限元分析承载力的40%取值。研究成果以期为木网壳非线性稳定承载力的进一步研究提供借鉴。

Nonlinear finite element analysis of stability of K6-type#br# single layer spherical timber latticed shell

In this paper, nonlinear finite element analysis on four experimental models with different joint types and rise-span ratios of reticulated glulam shell is carried out with the Beam189 element, which is a nonlinear beam element, to simulate the semi-rigid joint in ANSYS. Then the load-deflection curve, failure modes and ultimate bearing capacity of finite element analysis and test results are compared to judge the feasibility of multi-segment beam method in stability analysis of timber reticulated shells. The research finds that: (1) The multi-segment beam method is in good agreement with the test results. The multi-segment beam analysis method can effectively reveal the failure mechanism of timber reticulated shells; (2)The rise-span ratio is the main factor affecting the failure mode of single-layer reticulated timber shells. The models with larger rise-span ratio are prone to strength failure, the models with smaller rise-span ratio are prone to stability failure, and the influence of joint stiffness on the models with smaller rise-span ratio is more obvious; (3) In elastic-plastic analysis, the ultimate bearing capacity of reticulated timber shells is suggested to be 40% of elastic analysis. The research results can provide a reference for the further study of the non linear stability bearing capacity of timber reticulated shells.