（太原理工大学建筑与土木工程学院，太原 030024）

［摘要］为了研究钢管与螺栓球组合试件超低周疲劳性能，设计了两端带螺栓球节点的管球组合试件模型。对三种管球组合试件进行了大位移循环加载试验，试验过程中观察试件中部塑性变形区域弯曲、凹陷、开裂的发展历程及最终破坏形态；通过对试验数据的合理分析，研究三种组合试件的滞回曲线、骨架曲线、刚度退化、滞回耗能性能等超低周疲劳性能。试验结果表明：三种不同螺栓规格与钢管规格的组合试件，钢管塑性铰的破坏历程与破坏形态都大致相仿，均经历弯曲、凹陷、裂纹、开口破坏的过程，开口破坏时塑性铰区域呈椭圆形；每一次循环加载力卸载为零时钢管均出现一定程度的残余变形，这种变形随着持续的循环加载而不断累积，呈增长趋势；不同螺栓的组合试件对骨架曲线非线性起点的承载力影响不大，但对极限承载力有影响；试件塑性铰凹陷时刚度急剧下降，破坏前压荷载下其刚度基本一致，分别为1.80，1.75，1.85。

［关键词］螺栓球网格结构；超低周疲劳试验；塑性铰；骨架曲线；滞回曲线

中图分类号：TU399文献标识码：A文章编号：1002-848X(2020)24-0019-05

Experimental research on ultra-low cyclical fatigue of  steel pipe and bolt ball combined specimens

ZHANG Jie, QIAO Yongqiang, LI Haiwang, SONG Xiayun

(College of Architecture and Civil Engineering, Taiyuan  University of Technology, Taiyuan 030024, China)

Abstract:In order to study the ultra-low cyclical fatigue performance of steel pipe and bolt ball combined specimens, a pipe-ball combined specimen model with bolt ball joints at both ends was designed. The large displacement cyclic loading test was carried out on the three kinds of pipe-ball combined specimens. During the experiment, the development process of bending, dent, cracking and the final failure form in the middle of the specimen was observed; through reasonable analysis of the test data, the ultra-low cycle fatigue performance of the three combined specimens, such as hysteresis curve, skeleton curve, stiffness degradation, and hysteretic energy dissipation performance, were studied. The test results show that for three combined specimens of different bolt specifications and steel pipe specifications，the breaking process and breaking pattern of the plastic hinge of the steel pipe are roughly the same, and they all undergo the process of bending, dent, cracking, and opening destruction, when the opening breaks, the plastic hinge area presents an elliptical shape; each time the cycle loading force is unloaded to zero, the steel pipe shows a certain degree of residual deformation, this deformation accumulates continuously with continuous cyclic loading, which presents an increasing trend; the combined specimens of different bolts have little effect on the bearing capacity of the nonlinear starting point of the skeleton curve, but has an influence on ultimate bearing capacity; the stiffness of the plastic hinge of the specimen decreases sharply when it is depressed, the stiffness under the compressive load before breaking is basically the same, which are 1.80, 1.75, 1.85.

Keywords:bolt ball grid structure; ultra-low cycle fatigue test; plastic hinge; skeleton curve； hysteresis curve

*国家自然科学基金项目（51578358）。

作者简介：张洁，博士研究生，Email:mayzj@126.com；通信作者：李海旺，博士，教授，博士生导师，Email: Ihwtut@126.com。