Resistência de colunas de aço formadas a frio com seção Ue exibindo interação global-global

Abstract

Recently, Dinis et al. (2020) reported that the current Direct Strength Method (DSM) global design curve underestimates the failure loads of fixed-ended cold-formed steel channel columns affected by global-global interaction (flexural-torsional and flexural). This work extends the scope of the previous studies, considering additional geometries, carefully selecting fixed-ended lipped channel columns for the development of numerical investigation of columns experiencing global-global interaction. The results presented and discussed consist of critical loads and respective buckling modes, post-buckling equilibrium paths and failure loads, obtained through geometrically and materially non-linear ANSYS shell finite element analyses. The analyzed columns show(i) cross sections and lengths that guarantee global-global interaction (buckling load ratio RG close to 1.0), (ii) several yield stresses (to cover a wide slenderness range) and, (iii) flexural-torsional and flexural initial geometrical imperfections, which share the same combined amplitude, obtained from preliminary buckling analyzes. The work explores the postcritical behavior of the selected columns, with special attention to the identification of the most detrimental critical-mode initial geometrical imperfection shape, in the sense that it leads to the lowest column flexural-torsional strengths and failure loads. The failure loads compiled in this work, added with those previously reported, are used to assess the current curves proposed by Dinis et al. (2020).