Estudo de elementos estruturais roliços de madeira

Zangiácomo, André Luiz

doi:10.11606/t.18.2007.tde-05102007-152856

Cited by 7 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These properties are estimated via experimental tests, which are standardized by regulatory codes, and aim to quantify such variables regarding certain mechanical stress conditions. The knowledge of longitudinal (E) and shear (G) elasticity moduli has great importance in a beam design, as well as other structural elements (ZANGIÁCOMO, 2007;CHRISTOFORO, 2011). In Brazil, wood bending is characterized in accordance with Brazilian standards as ABNT NBR 7190: 1997 (Designing of Wooden Structures), which recommends static bending tests at three points within a beam, using flawless small specimens.…”

Section: Introductionmentioning

confidence: 99%

Elasticity moduli in round wooden beams of Pinus caribaea

2016

View full text Add to dashboard Cite

This research aimed at estimating both longitudinal (E) and shear (G) elasticity moduli of round structural-sized beams made of Pinus caribaea timber, verifying thus the validity of the G = E/ 20 relationship established by the Brazilian standard ABNT NBR 7190: 1997 (Designing of Wooden Structures). We tested twenty pieces of green wood with average length, diameter and conicity of 750 cm, 30 cm and 4%, respectively. Two static bending tests were applied at three points of each piece, being nondestructive and using different distances between supports. In the first trial, the length and diameter relationship (L/ d) was set as being equal to 24; yet in the second test, it was set at 12. The elasticity moduli were estimated by a successive use of the Timoshenko beam theory equation, which take s into account the shearing stress effect on displacement calculations. The results of both longitudinal and shear moduli were related through the least square assessment method; thus, we could find a relationship of G = E/ 43. As a result, we observed that the tested wooden pieces are at odds with the Brazilian standards.KEY WORDS: Stiffness, bending, beam theory, least square. MÓDULOS DE ELASTICIDADE EM VIGAS ROLIÇAS DE MADEIRA Pinus caribaea RESUMO:Este trabalho objetivou avaliar os valores dos mód ulos de elasticidade longitudinal (E) e transversal (G) em peças roliças estruturais de madeira Pinus caribaea, de maneira a se verificar a validade da relação G=E/20 estabelecida pela norma brasileira ABNT NBR 7190:1997 (Projeto de Estruturas de Madeira). As vinte peças de madeira (verde) testadas apresentam comprimento médio de 750 cm, diâmetro médio de 30 cm e conicidade média de 4%. Foram realizados dois ensaios de flexão estática a três pontos por peça, conduzidos de forma não destrutiva, diferenciados apenas pelas distâncias entre os apoios. No primeiro ensaio, foi utilizada a relação (L/d) entre comprimento (L) e diâmetro (d) das peças igual a vinte e quatro; e, no segundo, realizado na sequência, com L/d igual a doze. Os módulos de elasticidade foram obtidos de acordo com o emprego sucessivo da equação da teoria de vigas de Timoshenko, que leva e m consideração a influência dos esforços cisalhantes no cálculo dos deslocamentos. Os resultados obtidos entre os módulos de elasticidade longitudinal e transversal foram relacionados pelo método dos mínimos quadrados, sendo encontrada a relação G=E/43, evidenciando, para as peças de madeira aqui investigadas, a divergência de resultados para com a norma brasileira. PALAVRAS-CHAVE:Rigidez, flexão, teoria de vigas, mínimos quadrados.

show abstract

Section: Introductionmentioning

confidence: 99%

Elasticity moduli in round wooden beams of Pinus caribaea

2016

View full text Add to dashboard Cite

show abstract

“…The wood itself as one of the oldest building materials, being used mainly because of its availability in nature, ease of handling, manufacturing and excellent relationship weight/strength [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Verification of Test Conditions to Determine the Compression Modulus of Elasticity of Wood

Ferro¹,

Icimoto²,

Almeida³

et al. 2013

ijaf

View full text Add to dashboard Cite

The obtaining the modulus of elasticity in compression of the wood with the use of dial gauges, fixed on opposite faces of the specimens, may lead to deformation values and consequently to different elastic modulus as a function of the faces chosen for its attachment, being the timber an anisotropic material. This study aimed to evaluate the influence of two distinct positions for setting the dial gauges (A and B) in wood specimens tested in compression, using the assumptions of the test methods and calculation of the Brazilian standard ABNT NBR 7190: 1997. The woods evaluated in trials were the Pinus elliottii and Corymbia citriodora, being used seven specimens per species. A specimen was taken to the rupture, obtained the values of the ma ximu m stress and strain (references) needed to obtain the elastic moduli of the six remaining specimens per species, certain non-destructively (two tests per piece). The results of analysis of variance revealed the equivalence between modules elasticity in compression parallel to the grain for both wood species investigated, resulting not significantly arrangement of dial gaugesto determine the properties of stiffness. However, the anisotropy of wood, these results cannot be extrapolated to other woods of the same or d ifferent species, justifying the setting of dial gauges in two different positions, allo wing for judging whether or not the equivalence between the modulus of elasticity.

show abstract

“…The wood is one of the oldest building materials, being used main ly because of its availability in nature, ease of handling, manufacturing and excellent weight/strength relationship [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Influence of the Wood Specimen Position on Calculus of the Bending Modulus of Elasticity

Icimoto¹,

Ferro²,

Almeida³

et al. 2013

ijme

View full text Add to dashboard Cite

For the anisotropy presented by wood, the established positions of the specimens in the bending test can significantly alter the properties of strength and stiffness. This study aimed to evaluate, with the aid of the Brazilian standard ABNT NBR 7190:1997, the influence of the wood specimens position to determine the bending modulus of elasticity. The wood species used in the trials (three point static bending) were Corymbia citriodora and Pinus elliottii, and used six specimens per species. Each piece gave rise to four experiments, performed with a non-destructive form, differentiated only by the position of the specimen in the bending test(sides: A -lowest; B; C; D -higher value), providing four values of elastic modulus per specimens. The experiments were considered non-destructive for the largest displacement value in trials does not exceed the measure L/200 (L-usable length of the specimen), ensuring physical and geometriclinearity fo r the woods tested, as established by the Brazilian standard. The results of analyses of variance showed statistical equivalency between the modulus of elasticity of both wood species, resulting in independence of the specimen position to determine the bending stiffness. Ho wever, by the orthotropic behaviour of wood, the results obtainedcannot be extrapolated to other woods of the same or different species, thereby justifying the change of the specimenposition in the bending test, allowing evaluate the equivalence or not between the modulus of elasticity.

show abstract

Estudo de elementos estruturais roliços de madeira

Cited by 7 publications

References 0 publications

Elasticity moduli in round wooden beams of Pinus caribaea

Elasticity moduli in round wooden beams of Pinus caribaea

Verification of Test Conditions to Determine the Compression Modulus of Elasticity of Wood

Influence of the Wood Specimen Position on Calculus of the Bending Modulus of Elasticity

Contact Info

Product

Resources

About