Análise teórica e experimental de treliças espaciais

Souza, Alex Sander Clemente de

doi:10.11606/t.18.2003.tde-11102003-164954

Cited by 5 publications

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“…Para os sistemas disponíveis no Brasil, a faixa de utilização para altura da treliça é de , onde é o maior vão da treliça (SOUZA, 2003).…”

Section: Altura Da Treliça Recomendaçãounclassified

“…Os dados experimentais para comparação foram obtidos pelo Eng. Alex Sander Souza como parte do programa de doutoramento (SOUZA, 2003 Foram concluídos cinco dissertações de mestrado: MAGALHÃES, João (1996); SOUZA, Alex Sander (1998); MAIOLA, Carlos (1999); VENDRAME, Adriano (1999) Elementos de dimensões e peso reduzidos -são facilmente transportadas e montadas.…”

Section: Introductionunclassified

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Análise numérica, via MEF, de ligações em treliças metálicas espaciais

Sampaio¹

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As treliças espaciais vêm sendo freqüentemente utilizadas, de forma bastante diversificada, mas seu principal uso é como cobertura de grande vãos.Recentemente, vários acidentes com este tipo de estrutura têm acontecido, principalmente devido a uma série de considerações adotadas para dimensionamento, as quais não condizem com a realidade. Neste contexto, foi feito um estudo do comportamento seguido por estas estruturas. Este trabalho apresenta uma análise teórica, via método dos elementos finitos, de modelos de treliça espacial de seção tubular circular. Tem como objetivo verificar o comportamento de cada sistema de ligação, modelado tridimensionalmente com elementos de casca, associado à treliça espacial, modelada em elementos lineares. Foram estudadas as tipologias usuais de ligação deste tipo de estrutura abordando os problemas causados pelas peculiaridades de cada sistema. Palavras-chave: treliça espacial, sistemas de ligação, variação de inércia, análise numérica, método dos elementos finitos. SAMPAIO, T. S. (2004). Numerical analysis, using FEM, of connections in metallic space trusses. M.Sc. Dissertation -Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, 2004.Space trusses have been very frequently used in many applications, but its main employment is as roofs of great areas. Recently, many accidents have been occurring with this type of structure, mainly because of a series of adopted design assumptions, which does not fit reality. In this context, the behavior of this type of structure was studied. This study presents a theoretical analysis, using finite element method, of space trusses composed by circular tubular sections. It has as an objective to verify the behavior of each connection system, modeled in 3D by shell finite elements, associated to a space truss, modeled in linear finite elements. The usual typology of connections used in this kind of structure was studied, considering the problems caused by peculiarities of each system.

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“…Para os sistemas disponíveis no Brasil, a faixa de utilização para altura da treliça é de , onde é o maior vão da treliça (SOUZA, 2003).…”

Section: Altura Da Treliça Recomendaçãounclassified

Section: Introductionunclassified

Análise numérica, via MEF, de ligações em treliças metálicas espaciais

Sampaio¹

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“…Figura 2.27 -Curva tensão-deformação do material (Vendrame, 2002 (Souza, 2003)................................................... Figura 2.33 -Numeração de nós / modelagem do nó treliça TE1 (Souza, 2003) (Souza, 2003) ............................ Figura 2.36 -Deslocamentos verticais (cm), Força aplicada = 101 kN (Souza, 2003) ............…”

Section: Figuraunclassified

“…Figura 2.23 -Características e dimensões do protótipo de ensaiado (Vendrame, 2002) Apresenta-se a seguir alguns dos resultados obtidos por Vendrame (2002) (Souza, 2003) As treliças espaciais são diferenciadas pelo tipo de ligação entre barras, seção das diagonais de apoio e a existência ou não de reforço no nó típico. Para todos os protótipos foram utilizados tubos de seção circular ϕ76x2,0mm nos banzos e ϕ60x2,0mm ou ϕ88x2,65mm nas diagonais.…”

Section: Lista De Tabelas Tabela Páginaunclassified

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Estudo numérico experimental de treliças espaciais feitas com tubos de aço com ponta amassada e espaçadores de madeira para corrigir as excentricidades nos nós de ligação

Casanova¹

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Space trusses made of tubes with flattened ends connected with a trespassing bolt (typical connection) are widely used due to its easy construction and economy with respect to patented connections. However, the typical connection is weak due to the eccentricity and reduced momentum of inertia that exists at the nodes due to the flattening process. In previous studies, it was observed that when correcting the eccentricity generated by converging tubes at the same node, using steel spacers, the truss can support more load considerably. However, the use of such spacers made of steel increased the cost of production and generated additional dead load. Thus, the objective of the present research is to replace the steel spacers for spacers made of wood, which are more economical and lighter. To assess the improvement in the bearing capacity of the truss, this work applied a numerical and experimental approach to exam the feasibility of using wood spacer. In the numerical study, a tubular tetrahedral spatial lattice with square base 2m by 2m and 0.7m height was used. In the numerical analysis the commercial Finite Element software, ANSYS Workbench 14.5 was employed. The numerical analyses considered the detailed geometry of the truss as well as the non-linear behavior of the material and geometry trying to model the truss as close to reality as possible. In the experimental study, three trusses with typical connections and "Maçaranduba" wooden spacers were tested. In these tests, it was observed that the wood spacers withstood the loads. Moreover, the bearing capacity of the truss was very similar to bearing capacity of the previous trusses using steel spacers. The types of deformation (buckling and local deformations) shown in the numerical model and in the experimental test were very similar. This similarity in the results highlights that the numerical model adequately predicted the collapse and deformed shape of the trusses observed in the lab tests. Therefore, in conclusion: the results show that the use of wood spacers is feasible and an alternative to replace steel spacers in trusses with less weight and cost.

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Numerical analysis of truss systems with stiffened flattened end-bars

Mazon

Sarmanho

Nunes

et al. 2018

Lat. Am. j. solids struct.

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Circular hollow sections are usually used in long-span roof truss systems. One of the typology for connecting elements in such structures involves the flattening of bar ends. This article presents the numerical analysis of a plane truss composed of circular hollow sections, in which diagonal bars have flattened ends. In this sense, a new flattening typology called stiffened flattening is proposed, characterized by a non-flat geometry, with the creation of stiffeners in the lateral edges of the diagonal flattened ends. The diagonal connecting system with the chord members uses connecting plates. The plates are welded to the chords and the diagonals are connected to latter through a single bolt. The numerical analysis using finite elements method was developed in two stages through ANSYS software with the Parametric Design Language APDL , in which parameters such as geometry, materials, element types, boundary conditions and loads are specified. A non-linear analysis was performed using shell elements on the chords, diagonals, plates and welds, and contact elements between the diagonals with stiffened flattened ends and the connecting plates. Initially, a numerical study of the connecting node and the stiffened flattened end was performed, and the results directed the modeling of the plane truss. The numerical results were calibrated with the experimental truss results in full scale. The numerical result of the plane truss was also compared to a theoretical study, considering the axial load eccentricity applied in the diagonal with stiffened flattened ends. The study was based on the consideration of combined effects of axial force and bending moment provided by the Brazilian standard ABNT NBR 8800:2008. The final results indicate that the numerical model proposed is efficient and has good correlation with the experimental and theoretical results.

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Análise teórica e experimental de treliças espaciais

Cited by 5 publications

References 0 publications

Análise numérica, via MEF, de ligações em treliças metálicas espaciais

Análise numérica, via MEF, de ligações em treliças metálicas espaciais

Estudo numérico experimental de treliças espaciais feitas com tubos de aço com ponta amassada e espaçadores de madeira para corrigir as excentricidades nos nós de ligação

Numerical analysis of truss systems with stiffened flattened end-bars

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