管桁结构KK型搭接节点滞回性能的数值分析

Numerical analysis of hysteretic behavior of unstiffened overlapped CHS KK-joints in steel pipe structures by finite element method

在管桁结构中,对于搭接节点隐藏焊缝焊与不焊的问题,现行GB 50017—2003《钢结构设计规范》对此部分焊接未作明确要求.为揭示KK型搭接节点隐藏焊缝焊接与否对节点抗震性能的影响,采用ABAQUS有限元软件中的4节点完全积分格式的壳单元S4建立有限元模型,对管桁结构KK型搭接节点隐藏焊缝焊接与否进行数值模拟,得到2种不同搭接方式下的KK型节点在往复荷载作用下的滞回曲线、骨架曲线及节点域的应力分布.分析结果表明:隐藏焊缝不焊接节点的滞回性能优越于隐藏焊缝焊接的节点;搭接节点的最大应力主要发生在支管的搭接处,为此搭接节点的搭接率尽量要小;沿主管轴线方向有间隙,而垂直于轴线方向的支管两两搭接的KK节点的滞回性能更优越.

In the tubular truss structure,the question whether hidden weld in unstiffened overlapped circular hollow sections（CHS）joints should be welded or not remains unclear in the stipulation of present China＇s steel structures design codes（GB 500172—2003）.In order to reveal the influence of welded or unwelded hidden weld of the CHS KK-joints on seismic performance of the joints,a finite element model was set up by using the shell-element S4 of 4-node full integral format in the finite element software ABAQUS and the numerical simulation was performed in connection with the question above mentioned.The hysteresis loops,skeleton curves and stress distributions on the node region were obtained for the KK-joints with two kinds of overlap under the action of reciprocal load.The analysis results showed that the hysteretic performance of un-welded hidden weld would be superior to the welded one.The maximum stress of the CHS KK-joints would occur mainly in that section where two bracing members were overlapped,so that the overlapping ratio of overlapped joints should remain as small as possible.The hysteretic performance of KK-joints of two mutually overlapped bracing member,normal to the truss axis would be more superior when there was gap in the axial direction of the truss.