空间KT型圆管搭接节点静力性能研究(Ⅰ)——试验、数值模拟及参数分析

Static behavior of multiplanar overlapped CHS KT-joints——Part I: experiment,numerical modeling and parametric analysis

以上海旗忠网球中心为工程背景,对平面内外均搭接的空间KT型圆管节点(空间KT-Ov型节点)的静力性能进行静力单调加载的试验研究和有限元非线性分析。介绍节点试验方案,分析搭接节点的受力性能,并以试验结果为依据,建立满足精度要求并通过试验校准的空间KT-Ov型节点数值分析模型;在此基础上进行几何无量纲参数和荷载参数的非线性有限元分析,考查无量纲参数对节点极限承载力的影响。结果表明,由于空间节点单T平面内腹杆的存在,用平面K型节点承载力公式来预测空间KT-Ov型节点承载力是不合适的,将有较大误差。参数分析表明,ζt对空间KT-Ov型节点承载力是有影响的;腹杆轴力比n TK对节点极限承载力的影响是独立的,不受节点几何参数变化的影响;|n TK|≤0.2时,进行节点承载力分析可忽略单T平面内腹杆所受轴力影响;无论单T平面内腹杆受压还是受拉,均会导致节点极限承载力的降低,在单T平面内腹杆不受力(即n TK=0)时,空间KT-Ov型节点极限承载力有最大值。

The static behavior of multiplanar CHS KT-joints overlapped both in KT-Ov joint） , which were utilized in the steel roof engineering of Shanghai plane and out of plane （ i. e. muhiplanar Qizhong Tennis Center, was investigated under monotonic loading test and nonlinear finite element analysis. The test procedure was presented in this work, and the bearing capacity and failure mode of the test joint were then explored. A finite element model of muhiplanar KT-Ov joints was presented and validated by comparing the failure mode and the ultimate bearing capacity with the experimental results, and good agreements with the test results can be observed. By using this model, the effects of dimensionless parameters on ultimate bearing capacity of KT-Ov joints were studied. FE analyzing results indicate that due to the configuration of three mutually overlapped braces, using the formula of uniplanar K-joints to predict the ultimate bearing capacities of KT-Ov joints may not be suitable. The results of FE parametric analysis show that the muhiplanar parameter srt has some influences on the ultimate strength; rtTK （axial force ratio of web member） as a decoupled parameter is independent of geometrical parameters; when [ nTK] ≤0.2, the effect of web member axial force in T-plane on the joint ultimate bearing capacity might be neglected ; the resistance of KT-Ov joint has a maximum value at nTK = 0, and it may decrease no matter whether the web member in T-plane is under compression or tension.