Q690D高强钢焊缝连接疲劳性能试验研究  

Experimental study on fatigue performance of Q690D high strength steel welded joints

作　　者：郭宏超[1] 万金怀 刘云贺[1] 王德法[1] Guo Hongchao;Wan Jinhuai;Liu Yunhe;Wang Defa(Xi＇an University of Technology,Xi＇an 710048,China)

机构地区：[1]西安理工大学,陕西西安710048

出　　处：《土木工程学报》2018年第9期1-9,共9页China Civil Engineering Journal

基　　金：国家自然科学基金(51308454);国家重点实验室科学研究计划项目(2017ZZKT-8);西安理工大学科技新星项目

摘　　要：文中对Q690D高强度钢材及其焊缝连接的疲劳性能进行试验研究,讨论Q690D母材、对接接头、十字接头三种连接形式的疲劳极限;拟合了S-N设计曲线,并与现行规范进行比较,对其疲劳特性及疲劳寿命给予评价。试验结果表明:Q690D母材与普通钢材相比表现出较高的疲劳抗力;GB50017设计曲线能较好评估循环次数大于30万对接接头的疲劳寿命,且具有足够安全储备;十字接头S-N设计曲线与AISC360规定的疲劳设计曲线吻合较好。采用电镜扫描分析不同阶段断口的微观形貌特征,并基于零塑性累积应变率假设得到疲劳损伤公式,讨论焊接缺陷对试件疲劳损伤的影响。断口形貌可以反映试件的疲劳损伤发展过程,损伤曲线又很好地解释了断口的形成机理。The fatigue performance of Q690D high strength steel and its welded joints were investigated, and the fatigue limit of Q690D base metal, butt joints and cruciform joints was discussed. The S-N design curves were fitted and compared with current design standards, thus fatigue properties and life were evaluated. The results indicate that the Q690D base metal shows higher fatigue resistance than plain steels, and the GB50017 design curve can be used to evaluate the fatigue life of butt joints with more than 300 thousand cycles, and has enough safety reserve. The S-N design curve of cruciform joints is in good agreement with the curve specified in AISC360. Scanning electron microscopy（SEM） was adopted to analyze the microscopic features of the fracture at different stages. The fatigue damage formula was obtained based on the assumption of zero plastic cumulative strain rate, and the effect of welding defects on fatigue damage of specimens was discussed. The fracture morphology can reflect the fatigue damage development process of the specimen, and the damage curve can also explain the formation mechanism of the fracture.

关 键 词：高强度钢材 焊缝连接 疲劳极限 断口形貌 疲劳损伤 

分 类 号：TU391[建筑科学—结构工程]