Resumo em Inglês:

Abstract The present study develops an innovated shear deformable theory and four finite element formulations based on a total potential energy variational principle for the analysis of steel beams strengthened with GFRP laminates. The present theory captures orthotropic properties of the GFRP laminae, GFRP lamina stacking sequences, partial interaction between the steel beam and the GFRP laminates, and shear deformations. Three examples are conducted for the validation of the present theory. Through comparisons, the system responses predicted by the present solutions are excellently validated against those of recent experimental studies and three-dimensional finite element analyses. Key results obtained in the present study include: (i) the responses of GFRP-strengthened beams are strongly influenced by GFRP fiber angle arrangements. (ii) The strengthening is the most effective for steel beams strengthened with a GFRP laminate stacked with fiber angles of 0 degree. Based on two parametric studies, the effects of the orthotropic GFRP lamina properties and GFRP laminate thicknesses on the system deflections are also investigated.

Resumo em Inglês:

Abstract A numerical analysis of fluid-body interaction is performed in this work in order to evaluate the influence of vortex and tornado-like flows on immersed objects. Velocity profile models are adopted to generate vortical flow fields based on time-dependent boundary conditions and a finite element formulation is used for spatial discretization, where eight-node hexahedral elements with one-point integration are adopted. In addition, an arbitrary Lagrangian-Eulerian (ALE) approach is proposed to describe the relative motion between vortex flow and immersed objects. The flow governing equations are discretized using an explicit two-step Taylor-Galerkin scheme and tornado flow fields are simulated using the Rankine Combined Vortex Model (RCVM) and the Vatistas Model. Turbulence modeling is performed using Large Eddy Simulation (LES) with the Smagorinsky’s sub-grid scale model. Problems involving moving and stationary tornadoes interacting with fixed and moving objects are analyzed, where significant aerodynamic forces are observed on the immersed bodies, producing also significant changes in the vortex flow characteristics.

Resumo em Inglês:

Abstract This article presents a study of the behavior of hybrid steel beams of I-profile cross section subjected to bending. Numerical models of finite elements were developed and validated in the ABAQUS software. In the models, lateral buckling with torsion was disregarded, since the beam will be laterally restrained, so that only local instabilities are present and thus evaluated. Analyses were divided into two stages: first, the elastic buckling analysis was carried out to obtain the critical buckling loads and the buckling modes of the beams; subsequently, analysis of the ultimate strength capacity of the beams was carried out considering residual stresses and initial imperfections. The numerical model was defined and a sensitivity study of the yield strength of the flange steel was carried out. The obtained results from the developed numerical model were satisfactory and, as expected, showed that the hybrid beams resist a greater bending moment effort when compared to their corresponding homogeneous beams.