钢管混凝土轴压短柱非线性有限元分析  

Nonlinear finite element analysis of axially loaded concrete-filled steel tubular stub columns

作　　者：丁发兴[1,2] 周林超[1] 余志武[1] 欧进萍[2] 

机构地区：[1]中南大学土木建筑学院,长沙410075 [2]哈尔滨工业大学土木工程学院,哈尔滨150090

出　　处：《中国科技论文在线》2009年第7期472-479,共8页

基　　金：国家自然科学基金重点资助项目(50808180);高等学校博士学科点专项科研基金(200805331064);湖南省自然科学基金资助项目(07JJ4014)

摘　　要：提出新的混凝土单轴受力和轴对称三轴受压应力-应变关系统一计算公式,应用连续介质力学,采用弹塑性法对圆钢管混凝土轴压短柱力学性能进行分析,指出该新公式可避免圆钢管混凝土轴压短柱荷载-应变曲线上升段刚度衰减过快的缺点。采用该新公式并应用ABAQUS有限元软件建立圆钢管混凝土轴压短柱有限元模型,根据圆钢管混凝土轴压短柱的弹塑性法分析结果,确定ABAQUS中混凝土塑性损伤本构模型的膨胀角为40°,然后通过有限元建模对典型的方形钢管混凝土、矩形钢管混凝土、方形带肋钢管混凝土、矩形带肋钢管混凝土和箍筋约束混凝土轴压短柱的荷载-应变曲线试验结果进行数值仿真分析,计算结果与试验结果吻合良好。采用ABAQUS有限元软件,对相同含钢率下的方形钢管混凝土、矩形钢管混凝土、方形带肋钢管混凝土、矩形带肋钢管混凝土和钢筋混凝土轴压短柱的荷载-应变曲线进行数值仿真分析,探讨各种短柱的受力性能和约束套箍作用,指出方、矩形钢管混凝土的约束套箍作用没有圆钢管混凝土明显,也没有钢筋混凝土明显,所以对方、矩形钢管混凝土轴压短柱采取加肋的办法不能提高其承载力,但可略微改善其延性。New unified formulas for stress-strain relations of concrete under uniaxial load and under axisymmetric triaxial compression were proposed. Based on continuum mechanics,elasto-plastic method was adopted to analyze the behavior of concrete-filled circular steel tubular （CFCT） stub columns under axial compression. When the new unified formula for axial stress-axial strain relations of concrete under axisymmetric triaxial compression was adopted,the defect of the axial compressive stiffness decaying fast at the ascending branch in load-axial strain relations of CFCT stub columns was avoided. Applying new unified formula for stress-strain relations of concrete under uniaxial load,ABAQUS was used to establish the finite element model and to analyze the behavior of CFCT stub columns. According to the results of the behavior by elasto-plastic method for CFCT stub columns,the dilation angle in plastic-damage constitutive model for concrete in ABAQUS was determined as 40°. Then the load-axial strain behavior of typical concrete-filled square steel tubular （CFST）,concrete-filled stiffened square steel tubular （CFSST）,concrete-filled rectangular steel tubular （CFRT）,concrete-filled stiffened rectangular steel tubular （CFSRT）,and reinforced concrete （RC） stub columns were analyzed by ABAQUS. The analytical results were in good agreement with the experimental results from references. Finally,the load-strain behavior of typical CFST,CFSST,CFRT,CFSRT,and RC stub columns under the same steel ratio were analyzed by ABAQUS. The behavior and confinement effect of these stub columns were discussed. The confinement effect of CFST and CFRT stub columns are lower than that of CFCT stub columns,even lower than that of RC stub columns. The load capacity is hardly improved and the ductility is improved slightly when the CFST and CFRT stub columns are stiffened.

关 键 词：工程结构 钢管混凝土 本构模型 有限元法 弹塑性法 

分 类 号：TU398.9[建筑科学—结构工程]