Distortional buckling behavior of high-strength cold-formed thin-walled steel lipped channel columns under axial compression

In this paper,a finite element(FE) model considering material nonlinearity and geometrical large deformation for distortional buckling behavior analysis of 550MPa high-strength cold-formed steel columns with lipped channel section under axial compression loading was established,and its suitability is verified by comparing the existing distortional buckling experimental results with two kinds of thicknesses.With this numerical simulation model,a detail parametric study is further carried out,including the thickness and length of the columns,and the mode and quantity of initial imperfections and the mechanism of distortional buckling is briefly analyzed as well.Results show that the thickness and length of the columns,and the mode of initial imperfections have great effect on the loadcarrying capacity of axially-compressed columns,and the in-plane buckling of lips is the main cause for distortional buckling.Finally,by comparing the distortional buckling capacity between the test and theoretical analysis,it is shown that the method suggested in this paper can be well used to predict the load carrying capacity of distortional buckling of cold-formed steel columns under axial compression.