Experimental and analytical assessment of buckling in perforated cold-formed steel angles

This study investigates the experimental and analytical buckling behavior of two-dimensional perforated equal-angle cold-formed steel (CFS) members subjected to pure axial compression. Unlike previous studies that primarily focused on solid or unstiffened CFS sections, the present work explores the influence of perforation and varying stiffener spacing on the structural stability of built-up angle sections. The specimens were tested under pinjointed boundary conditions, with and without intermediate stiffeners placed at 50 mm, 100 mm, and 150 mm spacing. Experimental results revealed that reducing the stiffener spacing significantly enhances the buckling capacity, with the 50 mm spacing configuration exhibiting the highest ultimate stress and improved structural integrity. A nonlinear finite element (FE) model incorporating geometric imperfections was developed using ABAQUS and validated against the experimental results. The close agreement in failure load and deformation patterns confirms the reliability of the FE model. The validated model was further utilized for a parametric analysis to examine the effect of stiffener spacing under different boundary conditions (bottom fixed–top free and bottom fixed–top pinned). The results contribute new insights into optimizing stiffener arrangements for improved buckling resistance in perforated CFS angle members.