EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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3 resultados
Resultados da Pesquisa
Item Refined elastoplastic analysis of plane steel frames under extreme dynamic loading.(2015) Silva, Andréa Regina Dias da; Batelo, Everton André Pimentel; Silveira, Ricardo Azoubel da MotaThere may be situations in which structures are subjected to dynamic loads with intensities sufficient to cause permanent deformation and to accumulate damage that leads to collapse. Under extreme loading these structures must be capable of absorbing a considerable amount of energy. Thus, if engineers are to conceive lighter, more slender constructions without compromising quality and security standards, then they must evaluate a structure’s dynamic behavior considering the material ductility. Complex theories such as nonlinear formulations can be used to reduce simplifications in the analysis/design process. This work evaluates the nonlinear behavior of plane steel frames under extreme dynamic loads. Steel is considered to be an elastoplastic material, and for loading/unloading conditions, the structural members’ plasticity state is controlled using the refined plastic-hinge method. With this refined method the cross section’s gradual plastification can be accompanied from the start of yielding until the complete plastification of the section (plastic-hinge formation). Residual stresses are also considered, and the adopted plastic resistance surface of the cross section is defined by the internal forces and by its geometric characteristics. The numerical examples presented demonstrated the applicability of the proposed numerical strategy where the refined plastic hinge model enables the energy dissipation through the plastic hinges.Item Nonlinear dynamic behavior and instability of slender frames with semi-rigid connections.(2010) Galvão, Alexandre da Silva; Silva, Andréa Regina Dias da; Silveira, Ricardo Azoubel da Mota; Gonçalves, Paulo BatistaThe free and forced nonlinear vibrations of slender frames with semi-rigid connections are studied in this work. Special attention is given to the influence of static pre-load on the natural frequencies and mode shapes, nonlinear frequency–amplitude relations, and resonance curves. An efficient nonlinear finite element program for buckling and vibration analysis of slender elastic frames with semi-rigid connections is developed. The equilibrium paths are obtained by continuation techniques, in combination with the Newton-Raphson method. The ordinary differential equations of motion of the discretized frame are solved by the Newmark implicit numerical integration method using adaptive time-step strategies. Three structural systems with important practical applications are analyzed: an L-frame, a shallow arch, and a pitched-roof frame. The results highlight the importance of the static pre-load and the stiffness of the semi-rigid connections on the buckling and vibration characteristics of these structures.Item CS-ASA : a new computational tool for advanced analysis of steel frames.(2013) Silva, Andréa Regina Dias da; Prado, Ícaro Machado; Silveira, Ricardo Azoubel da MotaEsse trabalho apresenta uma nova ferramenta computacional, para análise avançada estática e dinâmica de estruturas de aço reticuladas planas, desenvolvida com base no Método dos Elementos Finitos. Duas fontes de não linearidades são consideradas nas análises: a geométrica, que considera os efeitos da deslocabilidade da estrutura; e a física, causada, principalmente, pelas características mecânicas dos materiais utilizados na construção civil. Imperfeições relacionadas com o carregamento, geometria do sistema e tensões residuais podem, também, serem consideradas. Para se ilustrarem alguns dos recursos e análises que diferenciam essa ferramenta dos programas comerciais existentes, a estabilidade estática e dinâmica de alguns sistemas estruturais, com ligações rígidas e semirrígidas, é avaliada. As respostas obtidas por outros pesquisadores são usadas, para validar as formulações e as metodologias de solução não linear, implementadas nessa ferramenta, e para atestar a eficiência desse programa caseiro de análise estrutural.