摘   要：针对薄壁方钢管混凝土在轴压下易产生局部屈曲问题，考虑材料本构关系的非线性，利用ANSYS程序建立了不带肋和带肋的薄壁方钢管混凝土组合柱的三维有限元模型；在普通钢管混凝土工作原理基础上，对带肋薄壁方钢管混凝土受力机理进行了探讨。揭示出受力过程中带肋薄壁钢管与核心混凝土截面应力分布发展规律及二者间的相互作用。结果表明，设肋后显著削弱钢管角部应力，增大核心混凝土区面积，即增强了对核心混凝土的约束效应，改善了薄壁方钢管混凝土柱的局部屈曲性能，增强了承载力和延性。

Abstract：Aimed at the problem on local buckling of thin-walled concrete filled square steel tubes under axial compressive loading, considering the nonlinear material constitutive relation, using ANSYS program to establish the three-dimensional finite element model of the non-ribbed and ribbed thin-walled concrete filled square steel tubes of composite columns, on the base of the working principle for common concrete with steel tubes, the stress mechanism of ribbed thin-walled concrete filled square steel tubes is discussed, which reveals the developing rules of stress distribution and the interaction between ribbed thin-walled steel tube and core concrete section in the stress process.The results show that the stress of steel tube corner is significantly weakened after ribbed, and increasing the area of core concrete, namely enhancing the binding effect on core concrete, can improve the local buckling performance of the thin-walled concrete columns filled square steel tubes, and enhance the bearing capacity and ductility.