Axial Compressive Strength of steel members made of cold formed angle sections

Abstract

AbstractCold formed sections often fail in three basic modes which are local, distortional, and global. Local and distortional modes are characterized by entire deformations, whether translation or bending of the plates forming the section. Current design codes determine the ultimate strength of short to intermediate cold formed angle columns based on the local‐global interactive failure modes. However, these cold formed angles sections fail in flexural‐torsional mode. Thus, the predicated ultimate loads are either unsafe or excessively safe depending on boundary conditions. Therefore, in this study the ultimate axial strength of pined‐pined columns composed of cold formed angles subjected to axial compressive force are determined numerically. A nonlinear finite element model has been developed using ABAQUS software. Four nodes isoparametric shell element that allows both geometric and material non‐linarites is used. The effect of geometric imperfections is included in the model. The parameters studied include, the angle leg width‐thickness ratios, overall member slenderness ratios. Further, Lipped as well as plain angles are considered in the study. Finally, results have been compared with the predicted strengths determined by the American specifications and the newly developed direct strength method, DSM.