新型不锈钢螺栓连接件疲劳后力学性能退化研究

Mechanical performance degradation simulation of new stainless steel bolt connector after fatigue

为探究装配式组合梁中新型不锈钢螺栓连接件疲劳后的力学性能,开展螺栓连接件疲劳后力学性能仿真方法研究。首先,基于当前螺栓连接件存在的问题与不足,设计了一种耐锈蚀、方便拆卸的新型螺栓连接件。其次,进行1组静载推出试验,4组不同疲劳加载次数后的静载推出试验,分析了试件破坏特征以及力学性能退化规律。最后,基于材料剩余强度理论,引入考虑疲劳损伤的混凝土和螺栓连接件的材料退化本构模型,建立不同疲劳加载次数后的螺栓连接件力学性能退化仿真计算流程,并对仿真结果进行了验证。结果表明:新型螺栓连接件疲劳加载270万次后剩余承载力退化了12.1%,且疲劳后破坏模式为螺栓剪断。采用的材料本构退化模型的仿真计算值与试验结果吻合较好,能够合理地反映螺栓在疲劳后的力学性能退化状况。

To explore the mechanical properties of new stainless steel bolt connectors in prefabricated composite beams after fatigue,the simulation method of mechanical properties of bolt connectors after fatigue was studied.Firstly,according to the pain points of current detachable connectors,a new type of bolt connector which is easier to use in practical engineering is designed.Secondly,one static push-out test and four static push-out tests after different fatigue loading times were carried out.The failure characteristics and mechanical property degradation rules of the specimens were analyzed.Thirdly,based on the material residual strength theory,the material degradation constitutive models of concrete and bolt connector considering fatigue damage were introduced,and the simulation calculation process of mechanical performance degradation of bolted joints after different fatigue loading times was established.Finally,the residual mechanical properties of the new stainless steel bolted joints after different fatigue loading times were verified.The results show that the residual bearing capacity of the new bolt connector is degraded by 12.1%after 2.7 million times of fatigue loading,and the failure mode after fatigue is bolt shearing.The simulation results of the material constitutive degradation model used in this paper are in good agreement with the experimental results,which can reasonably reflect the performance degradation of the bolt after fatigue.