INFLUENCE OF SLOPE OF GRAIN IN SHEAR STRENGTH OF WOOD
DOI:
https://doi.org/10.5902/1980509822754Keywords:
fracture mechanics, slope of fibers, eucalyptus.Abstract
The shear stress as a function of the inclination of the wood fibers were determined through experimental tests. The test specimens were obtained from a sample of wood beams 12 Eucalyptus saligna, following the requirements of NBR 7190. They were made with variable slope fiber (0 º, 15 º, 30 º, 45 º, 60 º, 75 º, 90 º). Through statistical analysis it was possible to estimate the parameters of variability of shear stress with the slope of the wood fibers. The shear stresses were corrected to standard moisture of 12%. With robust statistical analysis of the data set, it was possible to define the empirical equations that best define this phenomenon. Equations proposed in the literature by Hankinson, Karlsen, DIN 1052 and Keylwerth, the formulation prescribed by DIN 1052, with necessary modifications, has a better fit to the experimental results.
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ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 7190: Projeto de estruturas de madeira, Rio de Janeiro 1979.
AMERICAN SOCIETY FOR TESTING AND MATERIALS. Standard methods of testing small clear specimens of timber. ASTM D-143-94. Annual book of ASTM Standards, 2007.
BODIG, J.; JAYNE, B. A. Mechanics of wood and wood composites. 2. ed. Florida: Krieger publishing company, 1982. 712 p.
DAHL, K. B.; MALO, K. A. Nonlinear shear properties of spruce softwood: experimental results. Wood Science and Technology, v. 43, p. 539-558, 2009.
DINWOODIE, J. M. Timber: a review of the structure–mechanical property relationship. Journal of Microscopy, v. 104, p. 3-32, 1975.
DUMAIL, J. F.; OLOFSSON, K.; SALME, N. L. An analysis of rolling shear of spruce wood by the Iosipescu method. Holzforschung, v. 54, p. 420-426, 2000.
EUROPEAN COMMITTEE FOR STANDARDIZATION. Eurocode 5 - Design of timber structures - Part 1-1: General - Common rules and rules for buildings, 2005.
FOREST PRODUCTS LABORATORY. Wood handbook: wood as an engineering material. Gen. Tech. Rep. FPL-GTR-113. United States Department of Agriculture, Forest Products Laboratory, 1999.
GREKIN, M.; SURINI, T. Shear strength and perpendicular-to-grain tensile strength of defect-free Scots pine wood from mature stands in Finland and Sweden. Wood Science and Technology, v. 42, p. 75-91, 2008.
HASSEL, B. I. et al. The single cube apparatus for shear testing – Full-field strain data and finite element analysis of wood in transverse shear. Composites Science and Technology, v. 69, p. 877-882, 2009.
KARLSEN, G. G. et al. Wooden Structures. 1. ed. Moscow: Mir Publishers, 1967. 638 p.
KOLLMANN, F. F. P.; CÔTÉ, W. A. Principles of wood science and technology: I Solid wood. 1. ed. Berlin: Springer, 1984. 592 p.
LIU, J. Y. et al. An improved shear test fixture using the Iosipescu specimen. Mechanics Cellul Materials, v. 231, n. 85, p. 139-147, 1999.
LIU, J. Y. New shear strength test for solid wood. Wood and Fiber Science, v. 16, n. 4, p. 567-574, 1984.
LIU, J. Y.; ROSS, R. J. Wood property variation with grain slope. In: 12TH ENGINEERING MECHANICS CONFERENCE, 17-20 May 1998. American Society of Civil Engineers. Anais… La Jolla, CA, USA, 1998.
LIU, J. Y.; ROSS, R. J.; RAMMER, D. R. Improved Arcan shear test for wood. In: INTERNATIONAL WOOD ENGINEERING CONFERENCE, 28-31 October 1996. Anais… New Orleans, LA, USA, 1996.
LOGSDON, N. B. Variação da tensão resistente ao cisalhamento paralelo às fibras em uma peça de dimensões comerciais de AMESCLA, Trattinickia burserifolia (Mart.) Wild. In: ENCONTRO BRASILEIRO EM MADEIRAS E EM ESTRUTURAS DE MADEIRA, 5. 1995, Belo Horizonte, Anais... Belo Horizonte: EEUFMG; CEFET; IBRAMEM, 1995. v. 2, p. 235-244.
LOGSDON, N. B.; JESUS, J. M. H. Influência do ângulo entre o esforço aplicado e a direção das fibras da madeira sobre a resistência ao cisalhamento. Revista Engenharia Civil, v. 37, p. 5-16, 2010.
OLIVEIRA, J. M. Q. Characterization of the shear behaviour of wood using the Arcan test. 2004. 164 f. Dissertação (Mestrado em Engenharia Civil) - Universidade de Trás-os-Montes e Alto Douro, Portugal, 2004.
SZÜCS, C. A. Estudo do comportamento da madeira a esforços inclinados, In: ENCONTRO BRASILEIRO EM MADEIRAS E EM ESTRUTURAS DE MADEIRA, 4., 1992, São Carlos. Anais... São Carlos: EESC-USP; IBRAMEM. 1992. v. 2, p. 53-60.
UKYO, S.; MASUDA, M. A new method for measuring the true shear strength of wood. In: WORLD CONFERENCE ON TIMBER ENGINEERING, 9., 2006, Portland, Anais… Portland, v. 3, p. 41-47.
WANGAARD, F. F. The mechanical properties of wood. 1. ed. New York: John Wiley & Sons, 1950. 377 p.
YAMASAKI, M.; SASAKI, Y. Elastic properties of wood with rectangular cross section under combined static axial force and torque. Journal of Materials Science, v. 38, p. 603-612, 2003.
YAMASAKI, M.; SASAKI, Y. Yield behavior of wood under combined static axial force and torque. Experimental Mechanics, v. 44, n. 3, p. 221-227, 2004.
YOSHIHARA, H. et al. Comparisons of shear stress/shear strain relations of wood obtained by Iosipescu and torsion tests. Wood and Fiber Science, v. 33, n. 2, p. 275-283, 2001.
YOSHIHARA, H.; FURUSHIMA, T. Shear strengths of wood measured by various short beam shear test methods. Wood Science and Technology, v. 37, p. 189-197, 2003.
YOSHIHARA, H.; MATSUMOTO, A. Measurement of the shearing properties of wood by in-plane shear test using a thin specimen. Wood Science and Technology, v. 39, p. 141-153, 2005.
