Numerical Evaluation of the Axial Resistance Force in Steel Column Design

Abstract

The finite element method (FEM) is a form of computational analysis that provides approximated results with acceptable accuracy. By using the FEM, developing theoretical models capable of properly analyzing the effects of the structural behavior under the influence of proposed imperfections becomes easier and more economical. Metal columns are elements that, when subjected to axial compressive forces, undergo a phenomenon called buckling. This phenomenon consists of the loss of stability in the element, causing a displacement in the buckling axis of the structure. However, some construction imperfections in the materials cause the buckling phenomenon to not have the classic behavior predicted in the studies by Euler. Therefore, this study will present a numerical analysis of metal columns in rolled profiles with parallel flanges. During the simulations, the variations in physical and geometrical  imperfections were evaluated with different distribution models. The purpose was to evaluate the influence of such imperfections on flexural buckling, comparing the results obtained with numerical simulations to those obtained analytically. As indicated by the results of this evaluation, the physical and geometrical imperfections influence buckling in the case of columns with low slenderness ratios, significantly decreasing their strength. For higher slenderness ratios, i.e., greater lengths, this effect is decreased.