Skip to main content

Advertisement

Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image
We’d like to understand how you use our websites in order to improve them. Register your interest.

Differences of tensile strength distribution between mechanically high-grade and low-grade Japanese larch lumber I: Effect of length on the strength of lumber

Abstract

An experimental study was conducted to evaluate the effect of length on the parallel-to-grain tensile strength of Japanese larch (Larix kaempferi, Carriere) lumber. Six hundred pieces of mechanically graded lumber were tested at gauge lengths of 60, 100, and 180 cm. The lumber was sorted into matched groups according to the dynamic Young's modulus measured by the longitudinal vibration method before the lumber was cut to the particular length. The averages of the dynamic Young's modulus of high-grade (H) and low-grade (L) specimens were 12.8 and 7.5 GPa, respectively. Using nonparametric estimates, the estimated length effect parameters of H and L were 0.268 and 0.304 for the 50th percentile and 0.121 and 0.256 for the 5th percentile, respectively. We then concluded that the different length effect factors between H and L could be used when using the lumber for practical purposes. The parameters of L were larger than those for H, and the parameters for 5th percentiles were smaller than the parameters for 50th percentiles. When two-parameter Weibull distribution functions were fitted to the strength data, the estimated shape parameters of the Weibull distribution by the parametric method were almost identifical to the inverse of nonparametric parameters except the 5th percentiles for H. The influence of defects such as knots on the lower tail of the strength distribution in H may be different from that in L.

References

  1. 1.

    American Society for Testing and Materials (1995) Standard practice for establishing allowable properties for visually-graded dimension lumber from in-grade tests of full-size specimens. ASTM D 1990-95. ASTM

  2. 2.

    Ministry of Agriculture, Forestry and Fisheries (1996) Japanese agricultural standard for structural glued laminated timber. Japan Plywood Inspection Corporation

  3. 3.

    Bohannan B (1966) Effect of size on bending strength of wood members. US Forest Service research paper FPL 56, pp 1–30

  4. 4.

    Barrett JD (1974) Effect of size on tension perpendicular-to-grain strength of Douglas-fir. Wood Fiber 6:126–143

  5. 5.

    Madsen B (1990) Length effects in 38mm spruce-pine-fir dimension lumber. Can J Civil Eng 17:226–237

  6. 6.

    Lam F, Varoglu E (1990) Effect of length on the tensile strength of lumber. For Prod J 40(5):37–42

  7. 7.

    Taylor SE, Bender DA, Kline DE, Kline KS (1992) Comparing length effect models for lumber tensile strength. For Prod J 42(2):23–30

  8. 8.

    Hayashi T, Miyatake A, Miyahara H (1997) Size effect on tensile strength of sugi laminae (in Japanese). Mokuzai Kogyo 52(1):15–19

  9. 9.

    Okohira Y, Masuda M, Suzuki N (1988) The size effect of tensile strength on western hemlock. Bull Faculty Bioresources Mic Univ 1:1–6

  10. 10.

    Madsen B, Buchanan AH (1986) Size effects in timber explained by a modified weakest link theory. Can J Civil Eng 13:218–232

  11. 11.

    Kadowaki T, Takeda T, Hashizume T, Yoshida T (1998) Length effect on tensile strength in Japanese larch laminae (in Japanese). In: Abstracts of 48th annual meeting of Japan Wood Research Society, Shizuoka, Japan, p 110

  12. 12.

    Madsen B (1992) Structural behaviour of timber. Timber engineering Ltd, pp 237–286

  13. 13.

    American Society for Testing and Materials (1994) Standard practice for evaluating allowable properties for grades of structural lumber. ASTM D 2915-94, ASTM

  14. 14.

    Hashizume T, Saitou K, Noda M, Ishihara S (1997) Performance of a Japan-made continuous mechanical grading machine and its adjustment (in Japanese). Mokuzai Gakkaishi 43:141–148

  15. 15.

    Sobue N (1986) Measurement of Young's modulus by the transient longitudinal vibration of wooden beams using a fast Fourier transformation spectrum analyzer. Mokuzai Gakkaishi 32:744–747

  16. 16.

    Arima T, Hayamura S, Maruyama N, Miyazawa S, Furusawa S (1990) Evaluation for modulus of elasticity and weight change of lumber by sound analysis (in Japanese). J Soc Mater Sci Jpn 39:1228–1234

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Takashi Takeda.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Takeda, T., Hashizume, T. Differences of tensile strength distribution between mechanically high-grade and low-grade Japanese larch lumber I: Effect of length on the strength of lumber. J Wood Sci 45, 200–206 (1999). https://doi.org/10.1007/BF01177726

Download citation

Key words

  • Mechanical grading
  • Tension parallel-to-grain
  • Weakest link theory