New Shear Assay for the Simultaneous Determination of Shear Strength and Shear Modulus in Solid Wood: Finite Element Modeling and Experimental Results


  • Aleksandra Sretenovic
  • Ulrich Müller
  • Wolfgang Gindl
  • Alfred Teischinger


Density, European larch, finite element analysis, Norway spruce, shear strength, shear modulus, solid wood


Using a new modified shear test set-up, the longitudinal shear strength and the shear modulus of solid wood were determined, and the resulting shear strength was compared to the widely used block shear test. The two studied wood species—Norway spruce and European larch—showed a clear increase of shear properties with increasing density. Regarding shear strength, the values determined with the ASTM D 143 block shear test were consistently, by a factor of 1.7, above those obtained with the new modified test setup. Finite element analysis revealed the cause for this difference. At a load situation leading to a theoretical shear stress of 6 N/mm2, obtained by dividing the applied load by the area of the shear plane, the distribution of shear stress in the ASTM block shear specimen is inhomogeneous. A high stress concentration near the loading edge (stress concentration factor = 2.3) is indicated, accompanied by low shear stress towards the opposite end of the shear plane. By contrast, shear stress is consistently high (5.8 N/mm2) across the larger part of the new modified shear test specimen, leading to fracture at a lower applied external load than is the case for the ASTM block shear specimen. The distribution and intensity of shear stress in the new test set-up are fairly close to the stress state required for the determination of shear strength and shear modulus, and the new method therefore appears very suitable for the determination of the shear properties of solid wood.


American Society of Testing and Materials (ASTM). 1992. Standard methods of testing small clear specimens of timber. ASTM D-143-83. Test methods of evaluating the properties of wood-base fiber and particle panel materials. ASTM D-1037-91. Vol. 04.09. Wood. ASTM, West Conshokocken, PA.nAskenazi, A. K. 1976. Anisotropy of wood and wood-base materials. 1st ed. Izdatelstvo Lesnaja Promuslennosty, Moscow, USSR (in Russian).nBodig, J., and B. A. Jayne. 1982. Mechanics of wood and wood composites. Van Nostrand Reinhold Co., New York, NY. P. 712.nCoker, E. G., and G. P. Coleman. 1935. Photo-elastic investigation of shear tests of timber. Selected Engineering Pap. No. 174, The Institution of Civil Engineers, London, England.nCramer, S. M., J. R. Goodman, J. Bodig, and F. W. Smith. 1984. Failure modeling of wood structural members. Structural Res. No. 51, Civil Engineering Dept., Colorado State Univ., Fort Collins, CO.nDin 52187. 1979. Testing of wood: Determination of ultimate shearing stress parallel to grain. Normenausschuß Holz im DIN.nDivos, F., T. Tanaka, H. Nagao, and H. Kato. 1998. Determination of shear modulus on construction size timber. Wood Sci. Technol.32:393-402.nEn 789. 2002. Timber structures—Test methods—Determination of mechanical properties of wood-based panels. Fachnormenausschuß 012 Holzbau.nForest Products Laboratory. 1999. Wood Handbook—Wood as an Engineering Material. USDA Forest Serv. Forest Prod. Lab., Madison, WI.nFoschi, R. O., and J. D. Barrett. 1976. Longitudinal shear strength of Douglas-fir. Can. J. Civil Eng.3(2):198-208.nHibbit, Karlsson & Sorensen, Inc. 2001. ABAQUS/CAE and Standard-User's Manual.nKeylwerth, R. 1951. Die anisotrope Elastizität des Holzes und der Lagehölzer. Deutscher Ingenieur-Verlage GmbH, Düsseldorf.nKollmann, F. P., and W. A. Cêté. 1968. Principles of wood science and technology, Springer-Verlag-Berlin, Heidelberg, New York.nLang, E. M. 1997. An alternative method for shear strength assessment. Forest Prod. Soc. Vol. 47, No. 11/12.nLiu, J. Y. 1984. New shear strength test for solid wood. Wood Fiber Sci.8(4):252-261.nLiu, J. Y. 2000. Effects of shear coupling on shear properties of wood. Wood Fiber Sci.32(4):458-465.nLiu, J. Y. 2002. Analysis of off-axis tension of wood specimens. Wood Fiber Sci.34:205-211.nMandery, W. L. 1968. Relationship between perpendicular compressive stress and shear strength of wood, Wood Sci.1:(3).nMüller, U., A. Sretenovic, W. Gindl, M. Grabner, R. Wimmer, and A. Teischinger. 2003. Effects of macro-and micro-structural variability on the shear behaviour of softwood. Submitted.nNiemz, P. 1993. Physik des Holzes und der Holzwerkstoffe. DRW-Verlag, Leinfelden-Echterdingen.nNorris, C. B. 1962. Strength of orthotropic materials subjected to combined stresses. USDA For. Prod. Lab. Rept. 1816. Madison, WI.nRadcliffe, B. M., and S. K. Sudarth. 1955. The notched beam shear test for wood. Forest Prod. J.5(2):131-135.nSell, J. 1989. Eigenschaften und Kenngröbßen von Holzarten. by LIGNUM, Schweizerische Arbeitsgemeinschft für das Holz, Zürich.nSoltis, L. A., and D. R. Rammer. 1994. Shear strength of unchecked glue-laminated beams. Forest Prod. J.44(1): 51-57.nSzalai, J. 1992. Indirekte Bestimmung der Scherfestigkeit des Holzes mit Hilfe der anisotropen Festigkeitstheorie. Holz Roh-Werk.50:233-238.nYlinen, A. 1963. A comparative study of different types of shear tests of wood. Paper presented at the Fifth Conference of Wood Technology. USDA Forest Serv., Forest Prod. Lab., Madison, WI.nZhang, W., and A. Sliker. 1991. Measuring shear moduli in wood with small tension and compression samples. Wood Fiber Sci.23(1):58-68.n






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