复杂循环路径下钢材弹塑性屈曲行为研究

ELASTIC-PLASTIC BUCKLING BEHAVIOR OF STEEL MATERIAL UNDER COMPLEX CYCLIC LOADING PATHS

复杂强震荷载作用下钢管混凝土柱中的钢管受压屈服后易发生局部屈曲,在杆系有限元模型中采用不考虑屈曲影响的钢材本构模型无法准确模拟钢结构构件的地震响应。为研究复杂循环荷载作用下钢材的屈曲行为,该文设计了强度等级分别为Q235和LYP160的30个钢材试件,并设计了多种复杂循环加载路径进行加载,获得了不同复杂循环荷载作用下钢材的弹塑性屈曲行为和应力-应变滞回关系。基于已有文献中的3种钢材循环本构模型:Légeron模型、GA模型和DM模型对试验结果进行对比分析和评价,结果表明:Légeron模型无法模拟钢材受压区服后的屈曲效应,GA模型中受压屈曲时的应力-应变规律与试验结果较为吻合,DM模型中受拉和受压卸载刚度与试验结果较为吻合。

After compressive yielding,local buckling will occur on steel tubes in concrete-filled steel tubular column under complex seismic loading.In a bar-system finite element model(FE model),the seismic response of steel structure members cannot be effectively simulated by steel constitutive models without considering the influence of buckling.To study the buckling behavior of steel under complex cyclic loading,30 steel specimens with strength grades Q235 and LYP160 were designed,and various complex cyclic loading paths were adopted to obtain the stress-strain hysteretic relation and elastic-plastic buckling behavior of steel under various complex cyclic loading.On the basis of three steel cyclic constitutive models in the literature:Légeron Model,GA Model and DM Model,the predicting results were compared and analyzed with the test results.It can be seen that Légeron Model fails to stimulate the buckling effect of post-compressive yielding steel,and in GA Model,the stress-strain properties of compressive buckling agree well with the experimental results.The unloading stiffness of tension and compression calculated by the DM Model agrees well with the test results.