节点刚度对管桁架拱稳定性的影响

为研究节点刚度对管桁架拱稳定性的影响,在节点弹簧单元和壳单元滞回性能一致性得到验证的基础上,采用往复荷载下的变刚度弹簧模型代替壳单元考虑节点的半刚性。弹簧模型的节点刚度方程由节点域壳单元模型在往复荷载加载作用下的骨架曲线确定。以矢跨比为0.29,跨度为50m的管桁架拱为算例,采用材料与几何非线性有限元法对节点域弹簧模型和普通模型进行稳定性分析。结果表明：“静力失稳模态”为空间管桁架拱的最不利初始缺陷形式;节点刚度对管桁架拱的承载力影响程度与考虑初始缺陷的大小、分布形式和荷载作用范围有关。

Influence Of Joint Stiffness On Arch Stability Of Tube Truss

In order to study the influence of joint stiffness on the stability of tubular truss arch, a variable stiffness spring model under reciprocating load was used to replace shell element to consider the semi-rigidity of joints on the basis of the consistency of hysteretic performance of spring element and shell element. The stiffness equation of the spring model is determined by the skeleton curve of the node shell element model under reciprocating load. Taking a tube truss arch with a span of 50m and a span of 0.29 as an example, the stability of the joint domain spring model and the common model is analyzed by using material and geometric nonlinear finite element method. The results show that "static instability mode" is the most unfavorable initial defect form of space tube truss arch. The influence degree of joint stiffness on the bearing capacity of tubular truss arch is related to the size, distribution form and load range of initial defects.