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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6 resultados
Resultados da Pesquisa
Item Numerical formulation for nonlinear analysis of concrete and steel shells with deformable connections.(2021) Silva, Amilton Rodrigues da; Dias, Luís Eduardo SilveiraA two-dimensional interface finite element capable of associating flat shell elements positioned one above the other was developed. The implemented interface element can physically simulate the contact between the flat shell elements and connect the reference planes of the shell elements above and below it. The formulation presented allows consideration of nonlinear behavior for the deformable connection as well as for the concrete and steel materials that make up the shell structure. One of the practical applications analyzed in this research is the numerical simulation of composite floors formed by a reinforced concrete slab connected to steel beams through a deformable connection. In this case, the concrete slab and the steel beams are discretized by flat shell elements and the deformable connection is discretized by two-dimensional interface elements. Experimental and numerical results from literature were used to validate the implemented elements. In the two examples analyzed, the results obtained for the displacements were close, with the difference, in the first case, being associated with uncertainties during the experimental test and in the second, the difference in theories used in the formulation of the implemented elements.Item Concentrated approaches for nonlinear analysis of composite beams with partial interaction.(2021) Carvalho, Tawany Aparecida de; Lemes, Igor José Mendes; Silveira, Ricardo Azoubel da Mota; Dias, Luís Eduardo Silveira; Barros, Rafael CesárioTwo plane displacement-based formulations with concentrated nonlinear effects for numerical analysis of composite beams are presented here. The effects of geometric nonlinearity, plasticity and partial shear connection are considered. In these two approaches, the co-rotational system is defined to allow large displacements and rotations in the numerical model. The first formulation is based to Strain Compatibility Method, where the sections strains are explicitly evaluated as well as the slipping at the steel-concrete interface. Thus, the axial and flexural stiffness of the cross section is determined in each step of the incremental-iterative process. The second methodology considers rotational pseudo-springs at the finite elements ends to simulate of plasticity. Further- more, the effects of partial interaction can not be simulated by the inherently rotational behavior of the pseudo-springs. Thus, the cracking and partial interaction effects are approached through effective moment of inertia defined by normative criteria. Four composite beams are simulated with these two formulations and compared by the load-displacements paths. In all numerical re- sult findings these formulations are closed and accurate to the experimental data presented in lit- erature.Item Numerical analysis of steel–concrete composite beams with partial interaction : a plastic-hinge approach.(2021) Lemes, Igor José Mendes; Dias, Luís Eduardo Silveira; Silveira, Ricardo Azoubel da Mota; Silva, Amilton Rodrigues da; Carvalho, Tawany Aparecida deA two-dimensional displacement-based formulation with a plastic-hinge approach for the numerical analysis of composite beams with partial shear connection is presented here. The co-rotational approach is applied in the numerical model to allow large displacements and rotations. The axial and transverse displacement functions are defined to avoid locking problems. The simulation of the materials and shear connection nonlinear behaviors are approached via the strain compatibility method (SCM), where the constitutive relations are explicitly used. The slip in the steel section–concrete slab interface is considered by the axial force decomposition in the cross-section level by the degree of composite action, without introducing degrees of freedom in the finite element. The numerical proposal of the present work is tested by simulating steel–concrete composite beams and comparing the obtained results with the experimental and numerical data already known. This formulation is verified as numerically stable and without locking phenomena, and good convergence with literature results was obtained. However, more refined finite element (FE) meshes are needed.Item Numerical analysis of the effect of partial interaction in the evaluation of the effective width of composite beams.(2017) Silva, Amilton Rodrigues da; Dias, Luís Eduardo SilveiraMost of the engineering problems involving structural elements of steel-concrete composite beam type are approximations of the structural problem involving concrete plates connected by connectors to steel beams. Technical standards allow the replacement of the concrete plate element by a beam element by adopting a reduction in the width of the plate element known as effective width. The effective width is obtained, in most technical norms, taking into account only the parameters of beam span length and distance between adjacent beams. Numerical and experimental works found in the literature show that this effective width depends on several other parameters, such as the width and thickness of the concrete slab, and the type of loading. The objective of this work is to verify the influence of the partial interaction in the evaluation of the effective width of composite beams formed by a concrete slab connected to a steel beam with deformable connection, being used in numerical simulation three types of finite elements: a plate element for nonlinear analysis of the concrete slab; a bar element for non-linear analysis of beams with cross-section defined by a polygon; and an interface element which connects the plate and beam elements, simulating the deformation effect of the shear connectors. In the studied examples, it was found that the reduction of the shear connection stiffness at the interface between the concrete slab and the steel beam leads to a decrease in the shear lag effect and, consequently, makes the effective width of the concrete slab closer to the its real width. In another example, curves are constructed to define the effective width of a composite beam with medium stiffness. Considering maximum stresses and maximum displacements, these curves are obtained by forcing the equivalence of the approximate model with the model closest to the real problem.Item An interface element for numerical analysis of flat plate/shell elements with deformable connection.(2018) Silva, Amilton Rodrigues da; Dias, Luís Eduardo Silveirahe use of numerical methods such as the finite elements method for solving structural analysis problems is becoming ever more efficient. An interface element capable of associating flat plate/shell element in three different combinations has been developed. In a structural analysis, when only the flat plate/shell’s finite elements are used in the discretization, some problems concerning dimensional variation of the transversal section, as well as overlapping of areas can occur. . The aforementioned problems can be solved by the developed interface elements that can also simulate a possible deformable connection that is existent in the association of materials with different characteristics, such as the composite steel-concrete elements. One of the applications of the finite elements developed is for the numerical simulation of composite steel-concrete elements, such as the composite beam formed by a reinforced concrete slab attached to a steel beam using a deformable connection. In this case, the concrete slab and the steel beam are discretized by the flat plate/shell element, and the deformable connection done by the interface elements. In the validation of the implemented elements, we used numerical and experimental results found in the literature, and analytical solutions considering the classical plate theory.Item Análise numérica de cascas de concreto ligadas com conexão deformável a vigas de aço usando elementos finitos de casca e interface.(2016) Dias, Luís Eduardo Silveira; Silva, Amilton Rodrigues da; Neves, Francisco de Assis das; Ribeiro, José Carlos Lopes RibeiroCom o crescente uso do aço na construção civil no Brasil, em especial na confecção de pilares e vigas em edifícios de múltiplos andares, é cada vez mais comum a presença de elementos mistos formados pela associação mecânica entre elementos de superfície de concreto e vigas de aço na construção civil. Geralmente essa associação mecânica é feita por conectores soldados ao elemento de aço e envolvidos pelo elemento de concreto. Devido à deformabilidade existente na ligação surgem deslocamentos relativos entre os elementos conectados. Esses deslocamentos poderão ser mais ou menos significativos dependendo da rigidez da ligação, ou seja, do número e do tipo de conectores utilizados. Nesse trabalho foram desenvolvidos três elementos finitos de interface capazes de associar elementos planos de casca em três diferentes combinações: elementos em planos paralelos sobrepostos; planos ortogonais; e elementos paralelos pertencentes ao mesmo plano. Esses elementos de interface podem ser utilizados para evitar a sobreposição de áreas, ou alteração das dimensões da seção transversal, quando se utiliza um modelo de discretização em elementos de casca para uma análise estrutural qualquer. Eles também têm a função de ligar os elementos de cascas de uma seção mista e simular o comportamento mecânico da conexão deformável. Os elementos de interface deverão ter graus de liberdade compatíveis com os graus de liberdade dos elementos de cascas aos quais serão conectados. Nesse trabalho será utilizado o elemento de casca com nove nós, o elemento unidimensional e bidimensional de interface de seis nós e dezoito nós, respectivamente, sendo todos com cinco graus de liberdade por nó (a nível local). Para viabilizar a montagem do arquivo de entrada de dados usando os elementos finitos propostos, foi desenvolvido um gerador de malha de elementos finitos. Por exemplo, para o caso de uma viga mista, definida a superfície de concreto, sua espessura, as posições das vigas de aço, forma e dimensões de sua seção transversal, o gerador de malha irá discretizar em elementos de casca a superfície de concreto e as vigas de aço inserindo elementos de interface nas regiões de contato entre as vigas de aço e a superfície de concreto. Na validação dos elementos implementados foram utilizadas soluções analíticas, resultados numéricos obtidos de softwares comerciais e resultados experimentais e numéricos da literatura.