高温后不锈钢-碳钢复合钢筋低周疲劳性能  

Low-cycle fatigue performance of stainless-clad bimetallic steel bars after exposure to elevated temperatures

作　　者：华建民[1,2] 王斐 薛暄译 黄乐鹏 陈增顺 王能[3] HUA Jianmin;WANG Fei;XUE Xuanyi;HUANG Lepeng;CHEN Zengshun;WANG Neng(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Lab of New Technology for Construction of Cities in Mountain Area(Chongqing University),Ministry of Education,Chongqing 400045,China;School of Management Science and Real Estate,Chongqing University,Chongqing 400045,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]山地城镇建设与新技术教育部重点实验室(重庆大学),重庆400045 [3]重庆大学管理科学与房地产学院,重庆400045

出　　处：《哈尔滨工业大学学报》2022年第4期150-160,共11页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金面上项目(51778087);国家自然科学基金青年科学基金(51808071);重庆市博士后特别资助项目(XmT20200011)。

摘　　要：为评估火灾后不锈钢-碳钢复合钢筋的低周疲劳性能,对8个温度梯度的不锈钢-碳钢复合钢筋试件进行了低周疲劳试验,获得了火灾后不锈钢-碳钢复合钢筋的滞回曲线和疲劳寿命。在此基础上,分析了不同温度对低周疲劳荷载下不锈钢-碳钢复合钢筋的最大拉压应力、塑性应变幅值以及能量密度的影响,并从微观角度观察了不锈钢-碳钢复合钢筋高温后的金相组织变化,讨论了其疲劳破坏模式。试验结果表明:当受火温度高于500℃时,不锈钢-碳钢复合钢筋的低周疲劳性能随温度增加先降低后升高,疲劳寿命和能量密度在700℃时到达最低点;高温导致不锈钢-碳钢复合钢筋疲劳强度降低,塑性应变增加;金相组织变化是高温后不锈钢-碳钢复合钢筋低周疲劳性能改变的原因,受火温度高于700℃时碳钢芯筋的金相组织发生改变,冷却后有粒状珠光体生成。结果明确了不锈钢-碳钢复合钢筋的低周疲劳破坏机理,揭示了经历不同高温的不锈钢-碳钢复合钢筋低周疲劳性能演化规律。In order to evaluate the low-cycle fatigue performance of stainless-clad bimetallic steel bars(SCBSBs)after fire,low-cycle fatigue test was carried out on SCBSB specimens with eight different temperature gradients,and the hysteretic curve and fatigue life of SCBSBs after fire were obtained.Based on the test results,the effects of exposure temperature on the maximum tensile and compressive stress,plastic strain amplitude,and energy density of SCBSBs were analyzed.The variation of the metallographic structure of SCBSBs was observed,and the failure modes were discussed.Results show that when the exposure temperature was higher than 500℃,the low-cycle fatigue performance of SCBSBs first decreased and then increased with the increase in the temperature,and the fatigue life and energy density reached the minimum values at 700℃.The fatigue strength and plastic strain of SCBSBs decreased and increased respectively after exposure to elevated temperatures.Changes in the metallographic structure resulted in the differences in the low-cycle fatigue performance of SCBSBs after exposure to elevated temperatures.The metallographic structure of carbon steel core bar was changed when the exposure temperature was higher than 700℃,and granular pearlite was formed after cooling.The results clarified the low-cycle fatigue failure mechanism of SCBSBs and revealed the evolution trend of low-cycle fatigue performance of SCBSBs after exposure to elevated temperatures.

关 键 词：金属材料 不锈钢-碳钢复合钢筋 低周疲劳 金相组织 断口形貌 火灾后性能 

分 类 号：TU51[建筑科学—建筑技术科学]