(郑州大学力学与安全工程学院， 郑州 450001)

摘要: 为研究焊缝类型和内加肋板对钢管相贯节点超低周疲劳性能的影响，开展了 3 个 X 形方圆钢管相贯节点的超低周疲劳试验，研究了节点的破坏形态，分析了节点处的应变分布规律，得到了节点的疲劳寿命。 试验结果表明:3个 X 形方圆钢管相贯节点的裂纹均起始于节点的鞍点位置，角焊缝和熔透焊缝 X 形方圆钢管焊接相贯节点均呈现出冲切破坏特征，并且焊缝形式未对节点的变形能力和疲劳寿命产生明显的影响。 主管采用的内加劲肋的节点呈现出拉伸断裂破坏特征，其变形能力较差，并且断裂破坏前没有明显的表面裂纹，断裂突然发生，因此在较高烈度的地震设防区，从节点的抗断裂性能和变形能力考虑，在工程设计中，不建议采用主管内加劲肋来提高节点的承载能力。

关键词: 钢管结构； X 形方圆钢管相贯节点； 超低周疲劳性能； 焊缝

中图分类号:TU391 文献标志码:A 文章编号:1002￣848X(2022)04￣0086￣07

DOI:10. 19701 / j.jzjg.20200280

Experimental study on ultra￣low cycle fatigue fracture of X￣shaped steel joints with circularhollow section braces to square hollow section chord

LI Xueting， HUANG Xuewei， ZHAO Jun， ZHAO Wei， GE Jianzhou， WANG Xufeng

(School of Mechanics and Safety Engineering， Zhengzhou University， Zhengzhou 450001， China)

Abstract: In order to study the effect of weld types and internal stiffening rib on ultra￣low cycle fatigue performance ofsteel tubular joints， three X￣shaped steel joints with circular hollow section (CHS) braces to square hollow section( SHS)chord were tested under ultra￣low cyclic loading and the failure modes of the joints were investigated. Meanwhile， straindistribution at the joints and fatigue life of the joints were obtained in the tests. The test results show that crack starts atthe saddle of joints for all three steel tubular joints， and punching failure is observed for the X￣shaped steel joint withCHS braces to SHS chord with fillet weld and X￣shaped steel joint with CHS braces to SHS chord with penetration weld；besides， the type of weld has no obvious influence on the deformation capacity and fatigue life of the joint. It shows tensilefracture failure characteristic for the steel tubular joint with internal stiffening rib in the chord， and the joint has verylimited deformation capacity. Furthermore， there are no obvious surface cracks before suddenly fracture failure of thejoints with internal stiffening ribs. Therefore， from the perspective of deformability and anti￣fracture performance under theearthquake action， it is not recommended to set internal stiffening ribs in steel tubes to enhance the bearing capacity ofthe joints in the seismic fortification zone with high intensity.

Keywords:steel tube structure； X￣shaped steel joints with circular hollow section braces to square hollow section chord；ultra￣low cycle fatigue performance； weld

∗国家自然科学基金项目 ( 51608487)， 河南省科技攻关项 目 ( 192102310221)， 河 南 省 高 等 学 校 重 点 科 研 项 目 计 划(17A130002)，郑州大学大学生创新创业训练计划项目(2019cxcy338)。

第一作者:李雪婷，硕士研究生，主要从事结构的力学性能研究，Email:1968246460@ qq.com。

[引用本文]李雪婷，黄学伟，赵军，等.X 形方圆钢管相贯节点超低周疲劳断裂试验研究[J].建筑结构，2022，52(4):86￣92. LI Xueting， HUANG Xuewei， ZHAO Jun， et al. Experimental study on ultra￣low cycle fatigue fracture of X￣shapedsteel joints with circular hollow section braces to square hollow section chord[J]. Building Structure，2022，52(4):86￣92.