基于折减因子的奥氏体不锈钢螺栓高温应力-应变模型  

Retention Factor-based Stress-Strain Models of Austenitic Stainless-Steel Bolts at Elevated Temperatures

作　　者：孙涛 王辉 张蕾 刘晓英 赵宏刚 蒋伟 成鑫磊 何小涌 SUN Tao;WANG Hui;ZHANG Lei;LIU Xiaoying;ZHAO Honggang;JIANG Wei;CHENG Xinlei;HE Xiaoyong(Army Logistics Academy of PLA,Chongqing 401331,China)

机构地区：[1]中国人民解放军陆军勤务学院,重庆401331

出　　处：《材料导报》2024年第5期52-60,共9页Materials Reports

基　　金：重庆市教育委员会科学技术研究项目(KJZD-K202112901)。

摘　　要：不锈钢螺栓具有显著的耐久性、延性和耐火性,因此它们被广泛地应用于栓接的半刚性节点中。不锈钢螺栓如同其基材(不锈钢棒材)一样,在常温和高温下都表现出平滑的非线性特征,并且它们的应力-应变曲线中没有明确定义的屈服点。这种材料行为可以用不同的材料模型来表征,其中最常用的是Ramberg-Osgood公式或其修订版。然而,在现存不锈钢的材料模型中,相关力学参数的预测公式并不适用于经受冷作硬化和冷铸工艺的奥氏体和双相体不锈钢螺栓。因此,本工作基于先前研究中高温下不锈钢螺栓的折减因子建立它们的非线性高温材料模型。倘若在五个常温力学参数(杨氏模量、比例极限、屈服强度、极限强度和极限应变)已知的情况下,基于高温折减公式计算某一温度下的五个力学参数,进而评估试验应力-应变曲线与预测曲线之间的相关性。这种预测方法表明预测曲线与试验曲线具有明显的一致性,说明基于折减因子所建立的高温材料模型具有准确的预测精度。因此,联合不锈钢螺栓的高温折减公式,基于常温下的五个力学参数就可以准确预测其在某一温度下的应力-应变曲线。Stainless steel bolts are increasingly used in bolted semi-rigid connections due to their remarkable durability,ductility,and fire resistance.Stainless steel bolts,like their base material(stainless steel bars),exhibit smooth non-linear characteristics at both ambient and elevated temperatures,and they do not have a well-defined yield point in their stress-strain curves.This material behavior can be analytically represented by different material models,the most popular of which is based on the Ramberg-Osgood formulation or its extensions thereof.However,the available prediction formulas for the associated parameters in the material model of stainless steels are not necessarily applicable to austenitic and duplex stainless steel bolts subjected to work-hardening and cold-forging processes.Therefore,this paper proposes a nonlinear elevated tempe-rature constitutive model for stainless steel bolts based on their high-temperature reduction factors from previous studies.Supposing that five mechanical parameters(Young’s modulus,proportional limit,yield strength,ultimate strength,and ultimate strain)are given at ambient temperature,and the reduction formulas derived for stainless steel bolts is used to obtain five mechanical parameters at a specified temperature and to evaluate the correlation of the tested stress-strain curve with the predicted one.This prediction methodology shows that the predicted curve is in clear agreement with the tested one,which is shown to be that the elevated temperature material model based on the reduction factor has consi-derable prediction accuracy.Thus,a stress-strain curve at a given temperature can be predicted based on five mechanical parameters at ambient temperature by combining the elevated temperature reduction equations for stainless steel bolts.

关 键 词：奥氏体不锈钢螺栓 高温 折减因子 应力-应变曲线 非线性本构模型 

分 类 号：TU391[建筑科学—结构工程] TG142.25[一般工业技术—材料科学与工程]