摘要
为研究螺栓球节点橡胶板式支座中锚栓在灾难地震中受弯剪发生超低周疲劳的断裂问题,依据现行规范设计了橡胶板式支座模型,采用双向加载法对其进行了大位移超低周疲劳试验,得到了四根锚栓的超低周疲劳破坏形态。并从宏、微观角度对锚栓断口进行了分析。结果表明:在往复荷载下,锚栓发生无明显塑性变形的较突然性断裂,为超低周破坏形态,其断口存在疲劳源区、扩展区和瞬断区等典型的疲劳断裂特征;且不同位置锚栓的受力方向和裂纹起裂时间、扩展速率均不同;同一锚栓断口上韧性断裂与脆性断裂特征并存,但总体表现为偏脆性断裂。可见,不同位置锚栓对裂纹扩展主要应力的影响不同。
In order to study the ultra-low cycle fatigue fracture of anchor bolt in the rubber plate bearing of bolt ball joint under disaster earthquake,a rubber plate bearing model was designed according to the current specification.The failure morphology of ultra-low cycle fatigue of four anchor bolts were obtained,through a large displacement ultra-low cycle fatigue test with two-way loading,and then the failure morphology were analyzed from macro and micro perspectives.The results show that under the reciprocating load,anchor bolts fracture suddenly without obvious plastic deformation,and belong to ultra-low cycle failure morphology.The fracture has typical fatigue fracture characteristics such as fatigue source area,propagation area and instantaneous fracture area.At different positions,the stress direction,crack initiation time and propagation rate of the anchor bolts are different.The characteristics of ductile fracture and brittle fracture coexist on the same fracture,but the overall performance tends to brittle fracture.In conclusion,at different positions,the main stress of anchor bolts that affect crack propagation are different.
作者
王龙
李海旺
宋夏芸
王兴宇
李艳英
WANG Long;LI Hai-wang;SONG Xia-yun;WANG Xing-yu;LI Yan-ying(Civil Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《科学技术与工程》
北大核心
2020年第24期9996-10002,共7页
Science Technology and Engineering
基金
国家自然科学基金(51578358)。
关键词
空间网格结构
橡胶板式支座
灾难地震
超低周疲劳
锚栓
断裂机理
spatial grid structure
rubber plate bearing
disaster earthquake
ultra-low cycle fatigue
anchor bolt
fracture mechanism
