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Journal of Wood Science

Official Journal of the Japan Wood Research Society

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Young’s modulus obtained by flexural vibration test of a wooden beam with inhomogeneity of density

Journal of Wood Science volume 52, pages 20–24 (2006)Cite this article

Abstract

The object of this study was to investigate the inhomogeneity of density within a beam from a relationship between the dynamic Young’s moduli from the Euler-Bernoulli elementary theory of bending (E n) and resonance mode numbers (n), which is plotted as the “E-n” diagram in this article. Rectangular beams with dimensions of 300 (L) × 25 (R) × 5mm (T) of Sakhalin spruce (Picea glehnii Mast.), Sitka spruce (Picea sitchensis Carr.), Japanese red pine (Pinus densiflora Zieb. et Zucc.) and white oak (Cyclobalanopsis myrsinaefolia Oerst.) were used for specimens. Small parts of beams were replaced with a small portion of another species to examine the influence of the inhomogeneity of density on E n. A free-free flexural vibration test was undertaken and E n was calculated by the Euler-Bernoulli theory. The resonance frequency of a specimen with inhomogeneity of density was simulated by modal analysis. The density distribution in the longitudinal direction of the specimen for which E n did not decrease monotonically with n was obtained. From the modal analysis, the inhomogeneity of density was equivalent to a concentrated mass attached to a uniform beam. The pattern of the E-n diagram was changed by replacing a part of the specimen with another species. Specimens for which E n did not decrease monotonically with n had a high density part because of indented rings, knots, or resin.

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Authors and Affiliations

  1. Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin Kenkyu Danchi-nai, Ibaraki, 305-8687, Japan

    Yoshitaka Kubojima & Mario Tonosaki

  2. Faculty of Science and Engineering, Shimane University, Matsue, 690-8504, Japan

    Hiroshi Yoshihara

Authors
  1. Yoshitaka Kubojima
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  2. Mario Tonosaki
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  3. Hiroshi Yoshihara
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Correspondence to Yoshitaka Kubojima.

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Kubojima, Y., Tonosaki, M. & Yoshihara, H. Young’s modulus obtained by flexural vibration test of a wooden beam with inhomogeneity of density. J Wood Sci 52, 20–24 (2006). https://doi.org/10.1007/s10086-005-0732-9

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  • DOI: https://doi.org/10.1007/s10086-005-0732-9

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