冷弯薄壁方钢管混凝土柱的非线性有限元分析

为了研究设肋方式、钢管厚度、钢材强度和混凝土强度对冷弯薄壁方钢管混凝土组合柱力学性能的影响,本文采用ABAQUS有限元程序,对冷弯薄壁方钢管混凝土组合柱进行非线性有限元分析,计算和分析了冷弯薄壁方形钢管混凝土组合柱轴压时的荷载-变形全过程关系曲线。给出了有限元计算中钢材和混凝土本构关系模型、钢管及其核心混凝土之间界面模型等确定方法,分析在轴压作用下四种不同截面形式的冷弯薄壁方钢管混凝土组合柱的力学性能和破坏模态,理论计算结果与试验结果吻合较好。研究表明,设肋能有效改善冷弯薄壁方钢管混凝土组合柱的力学性能,与不带肋截面钢管混凝土构件相比,四边肋截面钢管混凝土构件的轴压承载力提高了9.4%~14.8%,十字肋截面钢管混凝土构件提高了18.7%~39.9%,而空钢管构件降低了65.3%~89.7%。同时,混凝土强度和钢管厚度对冷弯薄壁方钢管混凝土柱的轴压承载力影响较大。

Nonlinear Finite Element Analysis of Concrete-filled Square Cold-formed Thin-walled Steel Tubular Columns

To study the effects of rib type,thickness of tube,strength of steel and concrete on the mechanical behavior of concrete-filled square cold-formed thin-walled steel tube columns,nonlinear finite element(FE) analysis on the square cold-formed thin-walled CFT columns was carried out by using ABAQUS software.The mechanical behaviour of square cold-formed thin-walled CFT columns with four different cross-section was analyzed under axial compression.The results of finite element analysis show good agreement with that of the experiments.It was concluded that ribs in the tubular can largely improve the axial compressive capacities of cold-formed thin-walled CFT columns.Compared with CFT columns without ribs,the axial compressive capacities of the columns with four ribs and with crossed ribs increase by 18.7%~39.9% and increase by 9.4%~14.8% respectively,but for hollow section steel tuber columns,the value reduce by 65.3%~89.7%.Strength of concrete and thickness of tube also affect the axial compressive capabilities of square CFT columns.