Numerical Analysis on Distortional Failure of Cold-Formed Steel Hat-Section Beams Under Non-uniform Bending

Cold-formed steel (CFS) members stand out among steel structures notably due to their lightness, structural efficiency (high strength-to-weight ratio) and versatility, however, given their high width-to-thickness ratio, are highly susceptible to instability phenomena (buckling). The objective of this research is to analyze the structural behavior of cold-formed steel hat-section beams under non-uniform bending about the major and minor-axis, regarding the risks of distortional failure. Through the Generalized Beam Theory, using the computational program GBTUL, the geometries where the distortional failure is predominant were selected and through the computational program ABAQUS, a shell finite element model was developed to perform the buckling and post-buckling analysis on the selected elements. The results obtained from the developed model-which include critical buckling moments, failure moments, equilibrium paths, deformed configurations and collapse mechanisms-show that the developed model adequately simulates the distortional buckling and post-buckling behavior of the considered CFS beams and demonstrate how loading affects such behaviors.