橡胶板式支座锚栓超低周疲劳断裂分析

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，依国家现行规规范设计并制作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，但总体均表现为偏脆性断裂。

Ultra low cycle fatigue fracture analysis of anchor bolt of rubber plate bearing

In order to study the ultra-low cycle fatigue fracture of anchor bolt in the rubber plate bearing of bolt ball joint in the disaster earthquake, a rubber plate bearing model was designed and made according to the current national code, and its large displacement ultra-low cycle fatigue test was carried out by using the two-way loading method, and the ultra-low cycle fatigue failure mode of four anchor bolts was obtained. The fracture of anchor bolt is analyzed from macro and micro perspectives. The results show that: under the reciprocating load, the anchor bolt has a relatively sudden fracture without obvious plastic deformation, which is an ultra-low cycle failure mode. The fracture has typical fatigue fracture characteristics such as fatigue source area, propagation area and instantaneous fracture area, and the stress direction, crack initiation time and propagation rate of the anchor bolt at different positions are different; the characteristics of ductile fracture and brittle fracture coexist on the same anchor bolt fracture But they are all brittle fracture.