钢管混凝土哑铃型轴压构件极限承载力有限元分析

提出了钢管混凝土哑铃型轴压构件极限承载力的有限元计算方法.有限元建模中,钢管与腹板采用壳单元,混凝土采用实体单元.对试验构件的分析表明,有限元计算值与试验值吻合良好,腹腔内的混凝土受钢管紧箍力作用的影响很小,其应力-应变关系可按普通混凝土考虑.应用有限元计算方法,对哑铃型钢管混凝土构件的极限承载力进行了参数分析.结果表明,腹板间距的增加对极限承载力的提高呈非线性增长,腹板高度的增加与极限承载力的提高基本上呈线性关系.相比较而言,腹板间距增加对构件极限承载力的提高的影响要大于腹板高度的增大对其的影响.在参数分析的基础上,对其简化计算方法的比较表明,简单迭加法比等效单圆管法与试验值和有限元计算结果更为吻合、也更安全.

Finite element methods on ultimate load - carrying capacity of CFST dumbbell shaped short columns under axial loads

A finite element method to calculate ultimate load-carrying capacity of CFST dumbbell shaped short columns under axial loads is presented.In the finite element model,shell element is used for steel tube and web;solid element is used for core concrete.The analysis of specimens shows that the predicted ultimate loads by the FE method coincide with tested results.The confining force have little effect on concrete inner the webs,so its stress-strain relation can be considered as that of concrete without confining force, the parameters study shows that the increase of the space between webs will make the ultimate load-carrying capacity increase nonlinearly,and the height of the web result it increase almost linearly.By comparison,the influence of the space between webs to the ultimate load-carrying capacity is more remarkable than that of the height of the web.Based on the parametric study,it is found from the comparison of the two simplified methods,the superposition simplified method coincide with tested ultimate load better and safer and simpler than the equivalent single-tube method to predict the ultimate load-carrying capacity of CFST dumbbell shaped short columns.