不同冷却条件下钛-钢复合钢材高温后力学性能和本构模型  

Post-fire mechanical properties and constitutive model of titanium-clad bimetallic steel in different cooling methods

作　　者：石宇[1,2] 罗泽巧 周绪红 薛暄译[1,2] 李军 SHI Yu;LUO Zeqiao;ZHOU Xuhong;XUE Xuanyi;LI Jun(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area of the Ministry of Education,Chongqing University,Chongqing 400045,China;Pangang Group Research Institute Co.,Ltd,Panzhihua 617000,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [3]攀钢集团研究院有限公司,四川攀枝花617000

出　　处：《建筑结构学报》2023年第2期177-187,共11页Journal of Building Structures

基　　金：国家自然科学基金项目(51890902);重庆市在渝院士牵头科技创新引导专项(cstc2021yszx-jcyj0003)。

摘　　要：钛-钢复合钢是一种拥有良好力学性能和耐腐蚀性能的双金属材料。为了准确评估火灾后钛-钢复合钢的剩余服役能力,对高温后不同冷却条件下钛-钢复合钢的力学性能进行了试验研究。试验结果表明:经过高温和冷却处理后,钛-钢复合钢的复合界面保持有效连接;在拉伸试验过程中,颈缩之前复层TA1与基层Q235保持协同变形;过火温度和冷却方式对钛-钢复合钢断裂模式有较大影响,根据基层和复层断裂顺序分为基层和复层基本同时断裂、复层先于基层断裂、基层先于复层断裂等3种破坏模式。与已有其他钢材试验结果的对比分析表明:与不锈钢S30408、S31608不同,钛-钢复合钢的弹性模量基本不受过火温度和冷却方式影响;高温后自然冷却条件下,钛-钢复合钢屈服应力显著高于常温的,而极限应力基本不受过火温度影响;水冷条件下,过火温度不超过600℃时,过火温度对钛-钢复合钢力学性能基本没有影响,而过火温度超过600℃后,随着过火温度升高钛-钢复合钢屈服应力和极限应力显著提高,这与其他钢材略有区别。基于试验结果拟合了钛-钢复合钢的三段式非线性本构模型,采用模型的预测结果与试验结果吻合较好。Titanium-clad bimetallic steel(TCBS) is a bimetallic material with good mechanical properties and corrosion resistance. To accurately evaluate the remaining service capacity of TCBS after fire, the mechanical properties of TCBS under different cooling approaches after heating treatment were investigated experimentally. The test results indicate that the bonding interface of TCBS specimens remain effectively connected after heating and cooling treatment. During the tensile test, the cladding layer TA1 and the base layer Q235 maintain cooperative deformation before necking. The exposure temperatures and cooling methods have a significant influence on the fracture modes of TCBS. According to the fracture sequence of the base layer and the cladding layer, it can be divided into three failure modes;that is the base layer and the cladding layer basically fractured at the same time, the cladding layer fractured before the base layer, and the base layer fractured before the cladding layer. The comparative analysis with the test results of other steels reveal that different from stainless steel S30408 and S31608, the effect of cooling methods and heating temperatures on the elastic modulus of TCBS can be neglected. Under the condition of cooling in air(CIA), the yield stress of TCBS is evidently higher than that of room temperature, and the ultimate stress is not affected by heating temperature. Under the condition of cooling in water(CIW), when the heating temperature did not exceed 600 ℃, the exposure temperature has little effect on the mechanical properties of TCBS;after the heating temperature exceeded 600 ℃, the yield stress and ultimate stress of TCBS increase significantly with the increase of heating temperatures, which is slightly different from other steels. Additionally, a three-segment nonlinear constitutive model of TCBS is fitted based on the experimental results, and a good agreement between the results is observed.

关 键 词：钛-钢复合钢材 高温后 冷却方式 力学性能 本构模型 

分 类 号：TU391[建筑科学—结构工程] TU317.1