低碳钢及其不锈钢复合钢材低周疲劳行为的对比研究  

COMPARISON OF LOW-CYCLE FATIGUE BEHAVIOR OF A LOWCARBON STEEL AND ITS STAINLESS-CLAD BIMETALLIC STEEL

作　　者：廖小伟 潘之钊 班慧勇[2] 宗亮[3] 孙博[1] LIAO Xiao-wei;PAN Zhi-zhao;BAN Hui-yong;ZONG Liang;SUN Bo(College of Civil Engineering,Zhejiang University of Technology,Hangzhou,Zhejiang 310023,China;Department of Civil Engineering,Tsinghua University,Beijing 100084,China;School of Civil Engineering,Tianjin University,Tianjin 300350,China)

机构地区：[1]浙江工业大学土木工程学院,浙江杭州310023 [2]清华大学土木工程系,北京100084 [3]天津大学建筑工程学院,天津300350

出　　处：《工程力学》2024年第11期79-87,共9页Engineering Mechanics

基　　金：国家自然科学基金项目(51908501,51908503)。

摘　　要：不锈钢复合钢材在土木工程结构中得到了越来越多的关注和应用,但是其在循环荷载作用下的力学行为还缺乏足够的认识。通过单轴拉伸试验和不同应变幅条件下的对称应变控制加载低周疲劳试验,对比研究了2 mm+10 mm热轧304+Q235B不锈钢复合钢材及其基层Q235B碳钢钢材的循环弹-塑性特性和低周疲劳寿命;结合数值模拟得到的疲劳试件截面应力分布,分析了复合钢材低周疲劳失效模式的力学机理。结果表明,在拉伸和循环荷载下,复层304不锈钢与基层Q235B碳钢之间均没有出现界面剥离现象;复合钢材及Q235B碳钢均表现出与加载应变幅正相关的循环硬化行为,且前者的循环应力响应大于后者;复合钢材的低周疲劳初始裂纹均出现在Q235B碳钢侧,这是由于复层不锈钢和基层碳钢不同的拉应力状态和塑性变形能力共同造成的,但是复合钢材与Q235B碳钢的低周疲劳寿命未表现出明显的区别。该批次304+Q235B不锈钢复合钢材具有良好的低周疲劳性能,可代替Q235B碳钢用于对腐蚀防护性能具有较高要求的工程构件中。The stainless-clad bimetallic steel has attracted increasingly concern and application in civil engineering,but its mechanical properties under cyclic loading still demand deeper understanding.Through uniaxial tensile tests and low-cycle fatigue tests controlled by symmetrical strain loading,this paper has comparatively investigated the cyclic elastoplastic behavior and low-cycle fatigue life of the hot-rolling stainlessclad 304+Q235B bimetallic steel and its substrate layer Q235B carbon steel.Based on the finite element results of the cross-section stress distribution at different tensile strain levels in the fatigue specimens,the mechanical mechanism of the low-cycle fatigue failure mode in the bimetallic steel has been discussed.The results indicate that no interface debonding of the tested coupons occurs under both tensile and cyclic loading conditions.Cyclic hardening which is positively related to the applied strain amplitudes is observed in both the bimetallic steel and its Q235B carbon steel,but the bimetallic steel exhibits the higher maximum cyclic stress.The fatigue cracking always initiates in the side of the Q235B steel,which results from the combined effect of the different stress states and plastic deformation capacities.However,the experimental low-cycle fatigue life of the bimetallic steel is similar to that of the Q235 steel.This batch of 304+Q235B bimetallic steel exhibits qualified low-cycle fatigue performance,which can be used as an alternative for the Q235B carbon steel in engineering structural components demanding higher corrosion resistance.

关 键 词：不锈钢复合钢材 低周疲劳 循环硬化 单轴拉伸 开裂机理 

分 类 号：TU391[建筑科学—结构工程]