Interação entre modos de flambagem de perfis de aço formados a frio: análise e método de dimensionamento estrutural

Abstract

Cold-Formed Steel (CFS) refers to structural members formed by bending flat, thin plates at room temperature into shapes that enhance their load-carrying capacity compared to the original plate, achieving a favorable strength-to-weight ratio. While these structures offer significant advantages, it's crucial to consider their elevated slenderness values. This can lead to the formation of thin-walled structures, which are prone to buckling modes, including local (L), distortional (D), and global (G) buckling. Global buckling includes bending (GF) and flexural-torsional (GFT) modes. These buckling modes can interact, resulting in local-global (LG), local-distortional (LD), distortional-global (DG), and local-distortional-global (LDG) interaction modes. Such interactions can significantly reduce the resistance of these structures compared to isolated modes. The primary method for designing cold-formed steel under axial compression is the Direct Strength Method (DSM). The DSM considers design methodologies for CFS members subjected only to local (L), distortional (D), and global (G) buckling modes, as well as the interaction between local-global (LG) buckling modes. However, the DSM does not cover the interaction between other buckling modes. This study proposes modifications to the DSM to address these interactions. The suggested modifications have been shown to effectively estimate the resistance of bars under axial compression, supported by both numerical and experimental results.