Numerical Analysis of Physical and Geometrical Imperfections in Cellular Beams

Abstract

Cellular beams are appropriate for large spans with relatively small loads or for conditions in which strain dictates dimensioning. Another important advantage of cellular beams is the possibility of passing utility ducts through the openings, which avoids cutting through the web of the beam or increasing the construction height, which occurs when the ducts pass under the beams. Geometrical imperfections result from a lack of straightness during fabrication of rolled profiles. Geometric imperfections are represented numerically by an initial curvature. Additionally, the physical imperfections of rolled profiles result from the appearance of residual stresses. The condition that creates residual stresses in steel is the result of thermal and mechanical industrial processes. In this study, numerical analyses are performed with cellular beams using Finite Element Method software. During the simulations, through non-linear geometric and physical analyses, geometric imperfections were varied, where lateral torsional buckling in cellular beams was considered as a function of the unrestrained length. In the boundary, conditions were restrained displacements in the axis X, Y, Z and rotation about X-axis, thus simulating the fork support. The beams are submitted to uniform bending and concentrated load. The results from the numerical analyses were compared with the calculation procedures, which verified that the results were significant.