【作者】 周鹏；

【导师】 崔佳；

【作者基本信息】 重庆大学 ， 结构工程， 2009， 硕士

【摘要】 空间KX型圆管相贯节点常出现在主次桁架相交或连接面外支撑的节点部位,是大跨度空间结构中常用的一种节点形式,但是在我国《钢结构设计规范》中却没有专门针对KX型相贯节点的承载力设计公式,这给设计工作带来了困难。本文运用ANSYS有限元程序,在考虑材料非线性和几何非线性的基础上,对空间KX型圆管相贯节点的静力性能进行系统而全面的研究,主要包括以下几方面的内容:①对节点进行有限元建模,主要讨论了不同边界条件、网格划分以及加载方式对节点承载力的影响,确定了与实际情况最为接近的有限元模型。通过与试验对照发现,本文建立的空间KX型圆管相贯节点有限元模型计算结果与试验结果较吻合,能较好的模拟实际节点的受力性能。②通过对162个有限元节点模型计算结果的分析和观察,总结了空间KX型圆管相贯节点的破坏形式,并将节点的力学性能与平面节点做了对比,最后重点研究了6个无量纲参数,即主管径厚比γ、支管管径与主管管径之比β、支管厚度与主管厚度之比τ、K支管与主管夹角θ、主管轴力与主管全截面屈服轴力之比n和X支管轴力与K支管轴力之比nK X对节点极限承载力的影响。分析表明,除τ外,其余参数对空间KX型节点极限承载力的影响均较为明显;主管受轴压时节点极限承载力下降,其降低程度可按本文建议的? n计算;K支管与X支管间存在几何尺寸加强作用,其加强程度可按本文建议的? KX计算;节点破坏时支管的极限荷载是相互关联的,其相关关系可参考本文建议的表达式。③应用最小二乘原理,对节点破坏时K支管的极限荷载与n KX的关系曲线?nKX进行非线性拟合,并在此基础上,提出了空间KX型圆管相贯节点极限承载力的设计公式。更多还原

【Abstract】 Multiplanar CHS KX-joint which is a kind of common joints is usually used in the place where primary and secondary truss intersect or out-plane elements brace. There are no relative specifications in Code for design of steel structure, that makes it difficult to design tubular KX-joints. This paper makes a comprehensive and systematic analysis about the static behavior of Multiplanar CHS KX-joints by ANSYS program which takes material and geometry nonlinearity into account. Here are the main content of this paper:①The ANSYS model of this joint is constructed. While modeling course, the influence of different boundary condition, mesh generation and loading method on the bearing capacity is mainly considered, finally the finite element model which is the most close to reality is determined. Through comparing the finite element results with the experimental ones, the result shows that the finite element model of tubular KX-joint used in this paper can simulate mechanical behavior of practical joint better.②Based on the analysis of 162 finite element results, this paper summarizes the failure modes, compares the behavior of multiplanar KX-joint with plane joint, and mainly studies the effect of 6 dimensionless parameters on ultimate strength of KX-joint, including ratio of diameter to thicknessγ, diameter ratio of primary to secondary tubesβ, thickness ratio of primary to secondary tubesτ, angle between K tube and primary tubeθ, ratio of axial force to totally section yield axial force n ,and axial force ratio of X tube to K tube. Analysis shows that it is obvious that the influence of all parameters exceptτon the bearing capacity of this joint; while the primary tube is compressed, the ultimate strength of KX-joint decreases, this paper suggest ? n could be used to calculate the decreased degree; there is a strengthening action between K tube and X tube, this paper suggest ? KX could be used to calculate the increased degree; while KX-joint destroy,the ultimate bearing capacities of primary tubes are interdependence, their relationship could refer to the recommended formula in this paper.③By means of least square method, the relation curve ? nKX between ultimate bearing capacities of K tube and nK X is nonlinearly fitted while joint destroy. On this basis, this paper proposes the design formula which could calculate the ultimate bearing capacities of multiplanar CHS KX-joint.更多还原