中文摘要：

在管桁结构中,对于搭接节点隐藏焊缝焊与不焊的问题,现行钢结构设计规范GB50017-2003对此部分焊接未作明确要求.为揭示K型搭接节点隐藏焊缝焊接与否对节点抗震性能的影响,在试验研究的基础上,采用ANSYS有限元软件中的三维四节点弹塑性壳单元shell181建立有限元模型,对管桁结构K型搭接节点隐藏焊缝焊接与否进行了数值模拟,得到了2种不同焊接方式下的K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两腹杆的搭接处,为此搭接节点的搭接率尽量要小点;ANSYS有限元结果与试验数据的吻合度较好,说明相贯节点的滞回性能的试验通过有限元模拟分析是可行的.

英文摘要：

In the truss structure of a steel pipe,the question remains unclear whether hidden weld in unstiffened overlapped circular hollow sections（CHS） joints is welded or un-welded as has been previously mentioned in China＇s steel structures design codes（GB500172-2003）.In an effort to reveal the seismic performance of welded or un-welded hidden weld of the CHS K-joints,an experimental study,examining the hysteretic behavior of the CHS K-joints under cyclic loads was studied numerically utilizing the finite element method,i.e.ANSYS finite element software.Finite element models were set up and used to calculate the CHS K-joints with three-dimensional 4-node structural elastoplastic shell elements（shell181）.The data of hysteretic curves,skeleton curves and the stress distributions around the intersections were obtained by the finite element analysis for the CHS K-joints respectively.The results show that in unstiffened overlapped CHS K-joints,hysteretic performance of un-welded hidden weld is superior to the welded.The maximum stress of the CHS K-joints occurs mainly in the section where the two bracing members overlap,therefore,the overlapping ratio of overlap joints should remain as small as possible.All of the numerical analysis results were in agreement,approximately with the corresponding test results for the CHS K-joints,which also verifies the applicability and reliability of the finite element method in the study of hysteretic behavior of tubular joints.