Local Interactive Buckling Behavior Of Cold-Formed Rectangular Tube

Local buckling is an important buckling mode of thin-walled and cold-formed steel columns, and the interactive behavior of component plate elements cannot be ignored. This paper is the research on the local interactive buckling behavior of cold-formed rectangular tube under uniform compression. The paper includes the following main contents: (1) An elastic interactive buckling model is presented on the basis of the theory of elastic plates. Under the equilibrium condition and deformation compatibility condition, analytical expressions are derived to predict the interactive bucking load Pcr. (2) The finite element program ANSYS is used to analyze the elastic buckling of rectangular tube, consequently the buckling load Pcr and the simulating formula for the restraint coefficient &, is obtained. The results derived from the program are compared with the British Standard and China Standard. (3) By using an elastic-plastic material model, the nonlinear analysis is taken on the rectangular tube and simply supported plate, and the ultimate carrying load capacity Pu is obtained. The results show that the buckling mode is in accordance with the assumption of elastic analysis, and so shows the ultimate mode. (4) By the value Pu of simply supported plate comparing with the Pu ofrectangular tube, the regulations are found between the interaction for the post buckling plates of rectangular tube and the flange-web width ratio bf/bw, as well as bf/t, bw/t,considering interaction of plates are also obtained.