螺栓球节点中高强度螺栓的超低周疲劳破坏特征  

Ultra Low Cycle Fatigue Failure Characteristics of High Strength Bolts in Bolted Spherical Joints

作　　者：张丹丹 李海旺[1] 张洁[1] 宋夏芸 ZHANG Dan-dan;LI Hai-wang;ZHANG Jie;SONG Xia-yun(College of Architecture and Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)

机构地区：[1]太原理工大学土木工程学院,太原030024

出　　处：《科学技术与工程》2020年第34期14166-14170,共5页Science Technology and Engineering

基　　金：国家自然科学基金(51578358)。

摘　　要：为研究大震下网格结构螺栓球节点的破坏特征及机理,设计了杆件与螺栓球节点组合试件,采用北京市佛力系统公司电液伺服结构试验系统对试件进行低周往复加载试验,加载制度为不对称等幅加载,获得了不同幅值加载下试件中高强度螺栓的变形特征。通过对高强螺栓断口的宏、微观分析探讨螺栓球节点中高强度螺栓低周疲劳破坏特征及机理,获得以下结论:随着加载制度中位移幅值增大,螺栓球节点组合试件中高强度螺栓的疲劳寿命减小,断口的疲劳源增加,扩展区面积减小,瞬断区表面不平整性程度提高;在较低位移幅值的加载制度下,螺栓的起裂机理偏向脆性断裂,随着加载制度位移幅值增大,高强度螺栓的起裂机理由脆性断裂向准解理断裂转变,螺栓断口的瞬断区呈现偏向韧性断裂的特征。In order to study the failure characteristics and mechanism of bolted spherical joints in grid structures under large earthquakes,a composite fitting with bolt-ball joints as weak links was designed.The low-cycle reciprocating loading was adopted by Beijing Foli Systems Co.,Ltd.electro-hydraulic servo structure test system.The loading system was unbalanced constant-amplitude loading,and the deformation characteristics of high-strength bolts in the specimens under different amplitude loads were obtained.Based on the macro and micro analysis of the fracture of high-strength bolts,the failure characteristics and mechanism of grid-structured bolt-ball joint composite specimens under large earthquakes were explored.The following conclusions are obtained.As the displacement amplitude increases,the fatigue life of the bolt is reduced,the fatigue source of the fracture is increased,the area of the expansion zone is reduced,and the degree of surface unevenness in the transient fracture zone is higher.At low displacement amplitudes,the crack initiation mechanism of the bolt is brittle fracture.With the increase of the amplitude,the crack initiator of the bolt in the combined test piece transitions from brittle fracture to quasi-cleavage fracture,and the transient fracture area of the bolt fracture is all ductile fracture.

关 键 词：网格结构 灾难地震 高强度螺栓 超低周疲劳 微观分析 

分 类 号：TU391[建筑科学—结构工程]