高强冷弯薄壁型钢卷边槽形截面轴压构件畸变屈曲性能研究

建立了考虑材料和几何双重非线性的550MPa高强冷弯薄壁型钢卷边槽形截面轴压构件畸变屈曲性能分析的有限元模型，并通过对两种厚度高强冷弯薄壁型钢轴压构件畸变屈曲试验已有结果的分析比较验证了其有效性；采用该模型进一步分析了厚度、长度、初始缺陷模式及幅值等参数对畸变屈曲轴压构件承载力的影响，并对轴压构件畸变屈曲发生机理进行了探讨。结果表明：厚度、长度和初始缺陷模式是影响畸变屈曲轴压构件承载力的主要因素，且卷边面内屈曲是槽形截面轴压构件发生畸变屈曲的主要原因。通过理论计算与试验结果的对比分析，表明可以采用建议方法计算此类复杂截面轴压构件的畸变屈曲承载力。

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 load-carrying 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.