Numerical investigation on the influence of imperfections in the local buckling of thin-walled Ⅰ-shaped sections

摘要

In this work, an appraisal of the influence of the residual stresses and geometric imperfections is carried out for thin-walled I-shaped sections covering both hot-rolled and welded profiles based on a numerical study using the Finite Element Method. The Eurocode 3 design provisions for local buckling are presented and evaluated in comparison to the numerical results. Several residual stress patterns and geometric imperfection's amplitude and shape are considered to determine their effect on the ultimate strength of the cross-sections.Additionally, it is described a procedure to assess the flange and web interaction under different imperfection assumptions, and its influence investigated. The conclusions from this study are that the Eurocode 3 design provisions for hot-rolled sections are appropriate, but should be further improved for welded sections, mainly because the influence of the welded residual stresses is detrimental for the cross-section capacity and its effect is not to accounted for adequately. Finally, this study provides relevant information for the numerical modelling of thin-walled I-shaped sections concerning the consideration of geometrical imperfections and residual stresses.