Validação numérico-experimental do colapso distorcional de colunas metálicas em perfil formado a frio

Abstract

This Works presents a numerical- experimental investigation of cold formed steel lipped channel columns under axial compression, subjected to distortional failure, in order to calibrate the numerical model developed by LANDESMANN & CAMOTIM ( 2013) and the study the applicability of the Direct Strength Method ( DSM) – which is prescribed in the Brazilian standard ABNT NBR 14762:2010 and in the American standard AISI S100:2016 – in the ultimate strength estimation. The buckling modes and the correspondent ultimate strength values were obtained by means of Generalized Beam Theory, through the GBtul code ( IST/Portugal). The experimental tests assessed 17 fixed-ended columns, with variable geometric proportions, aiming to study if those aspects influence the distortional post-bubkling behavior. Measurements of initial imperfections and steel’s mechanical properties were also taken prior to compression tests. The equilibrium paths, ultimate strength and deformed configurations ( including the failure mode) provide relevant results for the description of the columns’ behavior. The calibrations of numerical model and validation of the experimental results were determined through ANSYS geometrical and material SFEA ( shell finite element analyses). The numerical results evidenced the arching of the columns’ end plates, changing their support conditions. The compilation of the columns’ ultimate strength experimental and numerical results is used in the assessment of the DSM design curves, as well as in the adjustment of a new equation for the observed support conditions.