Percorrer por autor "Souza, Jean Marcos Teixeira de"
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- In-plane thermo-mechanical behavior of curved beams with constant curvaturePublication . Souza, Jean Marcos Teixeira de; Mesquita, L.M.R.; Rocha, MarinaVigas curvas e arcos feitos em aço são estruturas provenientes de processos mecânicos de encurvamento de elementos retos, geralmente vigas de perfil I ou H, com objetivo de obter a geometria desejada, para atender requisitos estéticos ou de projeto. Este tipo de elemento apresenta comportamento diferenciado quando comparado com membros retilíneos, com modos de instabilidade específicos e diferentes respostas aos diversos tipos de carga. Por estes motivos, tais estruturas comportam-se distintamente quando submetidas a situações de incêndio ou temperaturas elevadas. Este trabalho estuda a estabilidade e a carga de colapso de vigas curvas e arcos em aço, curvados segundo seu eixo de maior resistência, por meio de análises numéricas de encurvadura no plano pelo Método dos Elementos Finitos.
- In-plane thermo-mechanical behavior of curved steel beams with constant curvaturePublication . Souza, Jean Marcos Teixeira de; Mesquita, L.M.R.; Nunes, Marina Rocha Pinto PortelaCurved steel beams and arches are structures originated from mechanical processes of curving straight members, usually I or H profiles, in order to get a desired geometry to attend aesthetics or project requirements. This type of elements behave differently when compared to regular straight members, with specific instability modes and different responses to various types of loading conditions. For these reasons, such structural members may react distinctively when submitted to fire conditions or elevated temperatures. This paper studies the stability and collapse load of steel curved beams and arches, curved by their major axes, through numerical Finite Element analyses for in-plane buckling at natural and elevated temperatures, simulating a fire event. Firstly, it was developed an analytical method to compute the internal forces based in energy methods for pin-supported arches under two point loads applied at one fourth of the length measured from the supports. Subsequently, linear elastic and nonlinear elasto-plastic buckling and ultimate load analyses were performed at both natural and elevated temperature conditions with the ANSYS Mechanical APDL Finite Element software package, for a variety of span and rise-to-span ratio values, support conditions and steel classes. These results were then compared to critical buckling load formulations found in the literature and to simplified methods presented in Eurocode 3 for elements under bending moments and axial forces. It is seen that support conditions play an important role in the thermo-mechanical response of steel arches, where fixed supports yielded much higher critical load results for every geometry and temperature case. However, even though superior steel classes provide higher resistant loads, regarding responses to thermal loads it was found that support condition is also more significant in this case. Moreover, the standard Eurocode 3 methodology for straight members was compared to the numerical results, which showed a good fit for lower bound loads except for higher slendernesses under elevated temperatures, where numerical solutions yielded result points under the standard resistance curves. Also, an analytical and experimental study on the cold-curving process of straight steel beams into arches using point loads was conducted, aiming to analytically define a post-curving residual stress profile and investigate the influence of elastic springback in the final shape of an arch.