不锈钢薄壁复合方钢管柱轴压局部屈曲研究

In order to explore the local buckling of thin-walled square hollow tubular columns made of bimetallic stainless steel plates under axial compression, the axially loaded tests were carried out on six stub specimens with different width-to-thickness ratios. The test results show that as the width-to-thickness ratio increases, the specimens gradually transform from strength failure to local buckling failure. The constitutive model of bimetallic steel plate was proposed based on the superposition principle. The finite element models of axially compressed square tubes were established by ABAQUS software. The finite element model was verified by test results. Based on the verified model, the effects of the width-to-thickness ratio (30-40) of the plates, the stainless steel content ratio (0-100%), and the type of bimetallic steel (Q235 + 304,Q355 + 316) on the local buckling of square steel tubes under axial compression loads were analyzed. The parametric analysis results show that the local stability coefficient of thin-walled square hollow tubes made of bimetallic stainless steel plates decreases with the increase in stainless steel content ratio. Local buckling failure can be avoided by limiting the width-to-thickness ratio. Based on the modified elastic modulus reduction factor under different stainless steel content ratios, a formula for predicting the critical stress of local buckling was proposed, and the limit value of the width-to-thickness ratio for thin-walled square hollow tubes made of bimetallic stainless steel plates was provided, which can be applicable to the two commonly used Q235 + 304 and Q355 + 316 bimetallic stainless steel plates.