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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11 resultados
Resultados da Pesquisa
Item Effect of chord length on CHS-RHS T-joints with slender sections.(2021) Pereira, Daniel José Rocha; Guerra, Messias Júnio Lopes; Sarmanho, Arlene Maria Cunha; Silva Neto, João Batista da; Nunes, Gabriel Vieira; Alves, Vinicius NicchioThe chord length is an essential geometric property that must be defined in the analysis of isolated joints composed of hollow steel sections, as well as the boundary conditions of the test. The analysis of these parameters’ effect on the behavior of joints has been addressed by other studies, mostly with joints between circular hollow sec- tions with compact or semi-compact cross-sections. Recent research about tubular joints has addressed cases with slender sections, where the design of joints containing these sections is still in development. In this context, this study aimed to evaluate the effect of the chord length in the behavior of T-joints between circular hollow section braces and slender rectangular hollow section chords through experimental tests and a numerical study considering the application of axial compression at the braces. The joint behavior was examined through the load-strain and load-deformation curves and the von Mises stress distribution, which allowed the failure mode's determination and the joint resistance value. Chord face failure was observed in the prototypes. It was concluded that a minimum chord length of 0.6m would be the adequate value for the study of the T-joints containing the geometric properties used in this study, which would be equivalent to a chord length five times higher than the width of the cross- section (5b0).Item Bearing failure in bolted sleeve connections with circular hollow sections under compression.(2020) Oliveira, Matheus Miranda de; Amparo, Lucas Roquete; Sarmanho, Arlene Maria Cunha; Pereira, Daniel José Rocha; Alves, Vinicius NicchioThis article analyzes sleeve connections between circular hollow sections. This type of connection is composed of two tubes connected by bolts to an inner tube with a smaller diameter, and explores the efficiency, aesthetics and resistance of hollow sections subjected to tension and compression. In previous researches, sleeve connec- tions with aligned and crossed bolt dispositions and under axial tension were studied. Herein, the behavior of sleeve connections with aligned bolts and under compression was analyzed. A model to represent the connection using the finite element method was developed, which allowed a numerical analysis with geometric property varia- tions. In the numerical/parametric results, bearing failure was observed in all cases, either in the outer or inner tube. Limiting the number of bolts to 6 and considering that connections have a lower outer thickness than the inner tube, a formulation was proposed to determine the ultimate bearing capacity of sleeve connections under com- pression and with bearing failure.Item Experimental and numerical assessment of CHS-RHS T-joints with chords subjected to axial tensile forces.(2021) Silva Neto, João Batista da; Nunes, Gabriel Vieira; Sarmanho, Arlene Maria Cunha; Pereira, Daniel José Rocha; Guerra, Messias Júnio Lopes; Alves, Vinicius NicchioHollow steel sections are widely used in the construction industry due to their mechanical properties. Joints used in these structures are the subject of research because of their singular and critical behavior. Joints containing chords with more slender cross-sections and axially loaded are still a challenge for design, especially in joints with circular hollow sections (CHS) in the braces and rectangular hollow sections (RHS) in the chords. In this context, this work aimed to study joints formed by a combination of CHS braces subjected to compression loads and RHS chords axially loaded with tension, welded as T-joints. Experimental tests, a numerical model using finite elements, and a parametric analysis were developed. A new equation for the chord stress function was proposed, including joints containing chords with semi-compact sections in tension. The joint resistance values obtained through the numerical models were compared with the equations from ISO 14346:2013 and with the proposed equation. It was observed that, for the numerical models with geometric properties inside the normative validity ranges of ISO 14346:2013, the mean rate of analytical by numerical joint resistance results was equal to 68%, using either the normative or the proposed equation. In the same way, for models outside the current validity ranges, either the proposed equation or the modified equation from ISO 14346:2013 could be used to design CHS-RHS T-joints with the geometric and material properties analyzed.Item Structural behaviour of thin-walled CHS-RHS T-joints : experimental and numerical assessment.(2021) Guerra, Messias Júnio Lopes; Pereira, Daniel José Rocha; Silva Neto, João Batista da; Nunes, Gabriel Vieira; Sarmanho, Arlene Maria Cunha; Lima, Luciano Rodrigues Ornelas deThe design of tubular joints with slender cross-sections is currently limited by the validity ranges of established international design standards. Aiming to assess the structural behaviour of tubular joints characterised by thinwalled chord cross-sections, this paper initially reports, an experimental investigation into tubular T-joints consisted of CHS braces welded to thin-walled cold-formed RHS chords, which slenderness values were outside of the current design standard limits. The experimental programme was carried out on 12 cold-formed steel slender cross-section prototypes where the braces were subjected to axial compressive loading. The geometric parameters, including chord and brace thickness and brace diameter were varied. The connected chord face failure was the failure mode observed in all tests. The results of the experimental tests were thoroughly discussed. A second step was used to calibrate a numerical model that was the basis for a parametric analysis involving the most relevant parameters affecting the joint’s behaviour. The obtained joint’s strengths were compared with those forecasted by ISO 14346 developed for compact cross-sections modifying the chord stress function concerning the elastic cross-section modulus and effective cross-section area when slender cross-section chords are concerned. However, this approach leads to scattered predictions, roughly too conservative. Finally, this paper proposes an alternative design approach for the studied joints that are more accurate in predicting their strength when compared to the presented experimental and numerical results.Item Bearing failure in bolted sleeve connections with circular hollow sections under compression.(2020) Oliveira, Matheus Miranda de; Amparo, Lucas Roquete; Sarmanho, Arlene Maria Cunha; Pereira, Daniel José Rocha; Alves, Vinicius NicchioThis article analyzes sleeve connections between circular hollow sections. This type of connection is composed of two tubes connected by bolts to an inner tube with a smaller diameter, and explores the efficiency, aesthetics and resistance of hollow sections subjected to tension and compression. In previous researches, sleeve connections with aligned and crossed bolt dispositions and under axial tension were studied. Herein, the behavior of sleeve connections with aligned bolts and under compression was analyzed. A model to represent the connection using the finite element method was developed, which allowed a numerical analysis with geometric property variations. In the numerical/parametric results, bearing failure was observed in all cases, either in the outer or inner tube. Limiting the number of bolts to 6 and considering that connections have a lower outer thickness than the inner tube, a formulation was proposed to determine the ultimate bearing capacity of sleeve connections under compression and with bearing failure.Item Análise numérica de ligações tipo T com perfis tubulares.(2019) Guerra, Messias Júnio Lopes; Nunes, Gabriel Vieira; Sarmanho, Arlene Maria Cunha; Pereira, Daniel José Rocha; Neiva, Luiz Henrique de AlmeidaNeste trabalho é apresentada uma análise paramétrica de ligações soldadas do tipo T formadas por perfis estruturais de aço sem costura, com seção transversal retangular no banzo e circular no montante. Um modelo numérico foi calibrado com resultados experimentais e após a calibração foi feito um estudo paramétrico variando os parâmetros (relação entre o diâmetro do montante e largura da face banzo conectado) e 2 (relação entre a largura e a espessura da face do banzo). Os resultados dos modelos numéricos, obtidos pelo critério de deformação limite, foram comparados com as prescrições mais recentes da ABNT NBR 16239 (2013) e da ISO 14346 (2013).Item Effect of fillet welds on T-joints with thin-walled chords.(2018) Pereira, Daniel José Rocha; Sarmanho, Arlene Maria Cunha; Nunes, Gabriel Vieira; Guerra, Messias Júnio Lopes; Alves, Vinicius NicchioTubular joints with thin-walled sections could have a wide range of applications in the construction industry, possibly providing light structures with high structural efficiency. However, current design prescriptions do not recommend their use and more studies are needed to attest their viability. In this context, the effect of the size of fillet welds on cold-formed T-joints consisting of thin-walled rectangular hollow section chords and circular hollow section braces under axial compression loading was analysed. Experimental and numerical analyses were conducted and the results were compared with current design prescriptions. Three experiments were performed, with different weld sizes, in a machine that provided displacement-controlled testing with data acquisition from strain gauges and displacement transducers. Finite-element models were developed to replicate the general experimental setup and the results showed good correlation with the experimental data, indicating that the size of the weld influences joint resistance.Item Cold formed steel semi rigid joints.(2018) Silva, Adriano Toledo da; Sarmanho, Arlene Maria Cunha; Nunes, Gabriel Vieira; Pereira, Daniel José Rocha; Neiva, Luiz Henrique de AlmeidaThis article presents a theoretical and numerical study of an innovative joint using cold-formed steel sections. The motivation for the study of this connection is the ease of manufacturing and assembly that it provides. The profiles are made of coldformed lipped channel sections, which are welded to form closed built-up sections on the columns and open built-up lipped sections to the beams. The beams use endplates connected by bolts (threaded bars) to the columns. The study evaluates the connection’s initial stiffness of 19 models, where the following parameters were varied: the thickness of the profiles and endplates, the height of the column sections and the diameter of the bolts. A theoretical and a numerical study were developed: the numerical study was performed using finite elements through the commercial software ANSYS, whereas the theoretical study was made based on the component method, prescribed by Eurocode 3, that does not include the design of the connection analyzed herein. Thus, aiming to enable the design of joints composed of cold-formed lipped channel sections, the analysis results were compared and an adjustment coefficient, proportional to the slenderness of the column’s plates, was proposed. The coefficient was introduced to the stiffness component that represents the column web in compression in the mechanical model. The ratio between the coefficients’ numerical and theoretical values presented a maximum variation of 11%, which was considered satisfactory.Item Análise paramétrica de ligações tipo “T” compostas por perfis tubulares de paredes esbeltas.(2018) Pereira, Daniel José Rocha; Sarmanho, Arlene Maria Cunha; Nunes, Gabriel Vieira; Lima, Luciano Rodrigues Ornelas de; Sarmanho, Arlene Maria CunhaPerfis tubulares de aço são muito utilizados na construção civil, podendo compor estruturas que oferecem grande resistência. Apesar das vantagens geométricas que tais perfis possuem, as prescrições de norma internacionais e nacionais não preveem a utilização de ligações entre perfis tubulares de maior esbeltez. Na busca de maior entendimento sobre esses perfis, neste trabalho foram analisados perfis tubulares com alta esbeltez por meio do comportamento de ligações do tipo “T” compostas por banzos de paredes esbeltas e montantes submetidos a carregamento axial de compressão. O estudo da ligação foi feito através de análise experimental e numérica, além da comparação com o que é atualmente previsto pelas prescrições normativas. Foram realizados três ensaios, com protótipos contendo diferentes tamanhos de cordão de solda para possibilitar a avaliação da influência da mesma no comportamento da ligação. Os ensaios foram realizados no Laboratório de Estruturas “Prof. Altamiro Tibiriçá Dias”, em uma prensa servo-hidráulica com controle de deslocamentos, sendo observado nos resultados, a influência do tamanho de cordão de solda na capacidade resistente da ligação. O estudo numérico foi feito via software comercial que utiliza elementos finitos (ANSYS), sendo seus resultados comparados aos experimentais. Os modelos apresentaram boa correlação com os dados dos experimentos, possibilitando a confiabilidade para desenvolvimento de uma análise paramétrica. No estudo paramétrico, através da variação do diâmetro do montante e da espessura do banzo, pôde-se observar que perfis com menores espessuras apresentaram maior dispersão de resultados em relação às equações teóricas, e que o critério de servicibilidade era dominante nesses casos.Item Análise numérica de ligações tipo “T” com perfis tubulares de paredes esbeltas.(2017) Guerra, Messias Júnio Lopes; Sarmanho, Arlene Maria Cunha; Nunes, Gabriel Vieira; Pereira, Daniel José Rocha; Silva Neto, João Batista daNeste trabalho é apresentada uma análise teórica e numérica de ligações soldadas do tipo “T” formadas por perfis tubulares de aço de seções esbeltas, com seção transversal retangular no banzo e circular no montante. Os estudos avaliam o comportamento, os modos de falha e a carga última da ligação. Foi analisada a influência dos parâmetros 2 (razão entre a largura e a espessura do banzo) e (razão entre o diâmetro do montante e a largura banzo). Os modelos numéricos em elementos finitos e os resultados foram comparados com as prescrições normativas recentes, utilizando o critério de deformação limite para determinação da carga última para o modo de falha de plastificação da parede superior do banzo.