Q345钢对接接头低周疲劳性能试验研究  

Experimental study on low cycle fatigue properties of Q345 steel butt joint

作　　者：周艳春[1] 李爱群[1,2] 方钊[1] 李万润[1,3] 

机构地区：[1]东南大学土木工程学院,南京210096 [2]北京建筑大学北京未来城市设计高精尖创新中心,北京100044 [3]兰州理工大学土木工程学院,兰州730050

出　　处：《东南大学学报（自然科学版）》2017年第4期738-742,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金重点资助项目(51438002);国家自然科学基金资助项目(51278104);中国博士后科学基金资助项目(2015M571641)

摘　　要：采用等幅轴向低周疲劳试验,通过疲劳寿命、循环应力-应变响应特征及应力-应变滞回曲线等指标研究了Q345钢对接接头的疲劳性能,观察了疲劳断口宏观特征,并在试验研究和有限元分析的基础上,建立了该焊缝材料的疲劳寿命预测公式.结果表明:焊缝材料初始阶段表现为明显循环硬化现象,后期为轻微循环软化,总体上提高了材料的强度及疲劳性能;随着轴向位移的增加,应力幅增大,循环硬化率线性减小;滞回曲线光滑、饱满,材料耗能能力稳定;疲劳断口可明显划分为裂纹源区、裂纹扩展区和裂纹瞬断区,为典型疲劳破坏断口.得到的疲劳寿命预测公式对实际工程中Q345钢结构的疲劳分析和寿命预测具有重要意义.By constant amplitude axial low cycle fatigue tests,the fatigue performance of butt weld joints made of Q345 was studied in terms of fatigue life,cyclic stress-strain response characteristics and stress-strain hysteresis loops,and the macro-characteristics of the fracture section were examined.Based on the fatigue test data and finite element analysis,the fatigue life prediction equation of the weld material was derived. The results show that the initial stage of the weld material is characterized by obvious cyclic hardening phenomenon,and the latter stage is slight cyclic softening. As a whole,the material strength and fatigue properties are improved. With the increase of the axial displacement,the stress amplitude increases and the cyclic hardening rate linearly decreases. The hysteresis loop is smooth and full,and the energy dissipation capacity of the material is stable. The fatigue fracture section is divided into crack source zone,crack propagation zone and crack transient fracture zone,and thus it is a typical fatigue fracture section. The obtained fatigue life prediction equation can provide important reference for the fatigue analysis and life evaluation of steel structures made of Q345.

关 键 词：Q345 对接接头 焊缝 低周疲劳寿命 有限元分析 

分 类 号：TU318.1[建筑科学—结构工程]