空间KK形圆管搭接节点静力性能试验研究与有限元分析

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KK形圆管节点（空间KK-Ov形节点）的静力性能进行了静力单调加载的试验研究和有限元非线性分析。详细介绍了节点试验方案，分析了搭接节点的受力性能、破坏模式、荷载-位移曲线及应变变化规律。在此基础上，建立了非线性有限元分析模型，对节点试验进行了数值模拟，计算结果与试验结果吻合良好。试验结果和有限元分析表明：空间KK-Ov形节点在发生承载力破坏时，常伴随有受拉腹杆与弦杆连接焊缝的开裂；四根腹杆交错搭接的构造，使得空间KK-Ov形节点具有明显区别于间隙节点破坏时管壁局部变形的特征，两受压腹杆之间的弦杆管壁在腹杆压力作用凹陷与腹杆局部屈曲是该类节点的主要破坏模式；平面外两腹杆搭接率ζ_t对节点承载力有一定影响，随平面外两腹杆搭接率的增大（即ζ_t绝对值变大），节点承载力将会减小。现行规范公式用于计算空间KK-Ov形节点承载力，既未考虑单K平面内搭接的影响，亦未考虑空间参数变化的影响，计算结果较试验结果偏于保守。

Experimental study and numerical analysis on static behaviour of multiplanar overlapped CHS KK-joints

The static behavior of multiplanar overlapped CHS KK-joints both in plane and out of plane(multiplanar KK-Ov joint), with the background of steel roof engineering of the Shanghai Qizhong Tennis Center, was investigated by test under monotonic loading and nonlinear finite element analysis. The test procedure was presented in the paper, and loading capacity, failure mode, load-displacement curve and plastic deformation of the experimental joint were further explored. Based on the test study, nonlinear finite element modeling was developed and used in numerical simulation of the experimental joint. The calculating results agreed well with the experimental results. Test result and FE analysis indicate that the welded seams between the tension brace and chord are often cracked when the KK-Ov joint failed. Because of the configuration with four mutually overlapped braces, local deformation of chord wall of multiplanar KK-Ov joints is distinctly different from that of multiplanar gapped CHS KK-joints, and statistic results reveal that the main failure mode of KK-Ov joints is CLD3+BLB, which means plastic failure and significant local deformation of the chord wall in the lap area occurring in the form of a radial fold and local buckling of the two compression braces. Multiplanar parameterζ_t has some influence on the ultimate strength. The current standard formula used to calculate the bearing capacity of this KK-Ov joint test is conservative.