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Official Journal of the Japan Wood Research Society

Evaluation of quality indexes of bending performance and hardness for hardwoods


The mechanical properties of 613 small clear specimens of 35 species (11 ring-porous hardwoods, 19 diffuse-porous hardwoods, and 5 softwoods) were evaluated. The aim of the study was to examine indexes of wood quality that are easy to measure and that exhibit a high correlation with bending performance and hardness that are essential properties of hardwood products. The modulus of rigidity, dynamic modulus of elasticity, bending properties (modulus of elasticity, modulus of rupture, stress at the proportional limit, absorbed energy, Tetmajer’s modulus), dynamic energy absorption by an impact bending test, compressive strength parallel to the grain, shear strength, partial bearing strength, and Brinell’s hardness were measured. A high correlation was found between dynamic modulus of elasticity and static modulus of elasticity. Bending stress at the proportional limit was found to be approximately equivalent to the compressive strength parallel to the grain. Static energy absorption correlated with dynamic energy absorption. Tetmajer’s modulus was found to be closely related to the ratio of the initial stiffness within the elastic range to the secant modulus at the maximum load. A high correlation was observed between Brinell’s hardness and partial bearing strength. The difference in the regression coefficients obtained for these correlations between the species groups was small.


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Correspondence to Akio Koizumi.

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Part of this study was presented at the All Division 5 Conference of IUFRO, Taipei, October 2007

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Teranishi, M., Koizumi, A. & Hirai, T. Evaluation of quality indexes of bending performance and hardness for hardwoods. J Wood Sci 54, 423–428 (2008).

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Key words

  • Small clear specimen
  • Quality index
  • Strength characteristics
  • Hardwood