Análise numérica da interação distorcional-global em vigas de perfis formados a frio do tipo cartola submetidos a flexão não-uniforme

Abstract

Cold-formed sections are very slender elements with thin-walled sections. This makes them subject to the phenomenon of buckling, which can be local, distortional, global and/or their interactions, which occurs when the structure shows that it is failing before the material reaches its ultimate strength. Thus, there is a need to understand these events to predict them in design and incorporate them into the latest standards. Therefore, the aim of this work is to conduct a numerical study of beams subjected to non-uniform bending, with a top hat profile as the cross-section, with a view to distortional-global interaction in their axes of greatest and least inertia. Using the GBTUL computer program, the geometries were identified so that the distortional-global interaction occurred, with modal participation greater than 95% local critical moment far from the distortional and global critical moment. In the ABAQUS computer program, which uses the finite element method, the buckling and post-buckling analyses were conducted. In these analyses, values were obtained which include the equilibrium trajectories of the elements, resisting moments, deformation configuration and collapse mechanisms, and these values showed that the design curve of the Direct Resistance Method does not adequately predict the resistance of the structures. Adjustments were therefore made to the equations to adequately predict the resistance capacity of the elements.