低周反复荷载下异形钢管混凝土柱力学性能有限元分析

Finite element analysis on mechanical properties of special-shaped concerete-filled steel tubular column under low cyclic loading

为了研究低周反复荷载下异形钢管混凝土柱的力学性能,以试验研究为基础,在参考常用的方钢管混凝土柱核心混凝土本构关系的基础上,提出了适用于L形钢管混凝土柱核心混凝土在低周反复荷载作用下的应力-应变关系,采用有限元程序Opensees,模拟了低周反复荷载下L形钢管混凝土柱的荷载-水平位移(p-Δ)关系曲线;分析了L形钢管混凝土柱抗震性能的影响因素.结果表明:计算结果与试验结果吻合较好;轴压比是构件骨架曲线的主要影响因素,随着轴压比的增大,试件的刚度逐渐变小,水平极限承载力变小,曲线将会出现下降段,且下降幅度有增大的趋势;截面宽厚比D/t和截面长宽比D/B对构件骨架曲线的影响相似,总体上对荷载-位移骨架曲线的形状影响很小,主要表现在对水平承载力大小的影响.

To study the mechanical properties of special-shaped concrete-filled steel tubular column under low cyclic loading,based on experimental study and stress-strain relationship of the core concrete in concrete-filled square steel tube columns subjected to low cyclic loading,those relations in concrete-filled L-section steel tubular columns are proposed and nonlinear finite element method analysis on L-shaped concrete-filled steel tubular column is carried out by Opensees software.The lateral load versus lateral displacement（P-Δ） curves and its influencing factors are analyzed.The results show that the calculation results are in good agreement with experimental results.The axial compression ratio is the main factor affecting the envelope curve of the member.As the increase of the axial compression ratio,the stiffness of the specimen and the horizontal loading capacity decreases.Meanwhile,the curve becomes descendent and the descent amplitude will increase as the increase of the axial compression ratio,which indicates that the ductility of the member becomes worse.The influence of the width-thickness ratio D/t on the envelope curve is similar to that of the length-width ratio D/B,which has little effect on the shape of the envelope curve but will influence the lateral loading capacity.