Skip to main content

Official Journal of the Japan Wood Research Society

Journal of Wood Science Cover Image

Changes in the mechanical properties of wood during a period of moisture conditioning

Abstract

Changes in the modulus of elasticity (MOE), modulus of rupture (MOR), and stress relaxation in the radial direction of wood (hinoki:Chamaecyparis obtusa) moisture-conditioned by the adsorption process from a dry state and by the desorption process from a moisture content slightly below the fiber saturation point were investigated. The MOE and MOR of wood conditioned by the adsorption process showed significant increases during the later stages of conditioning when the moisture content scarcely changed. However, with the desorption process they did not increase as much during later stages of conditioning, though they increased during early stages of conditioning when the moisture content greatly decreased. The stress relaxation of wood decreased with an increase in the conditioning period with both the adsorption and desorption processes. These results suggest that wood in an unstable state, caused by the existing state of moisture differed from that in a true equilibrium state shows lower elasticity and strength and higher fluidity than wood in a true equilibrium state. Furthermore, the present study demonstrates that the unstable states of wood induced during the course of drying, desorption, and possibly adsorption of moisture are slowly modified as wood approaches a true equilibrium state.

References

  1. 1.

    Furuta Y, Norimoto M, Yano H (1998) Thermal-softening properties of water-swollen wood. V. The effect of drying and heating histories (in Japanese). Mokuzai Gakkaishi 44:82–88

    CAS  Google Scholar 

  2. 2.

    Ishimaru Y, Narimoto S, Iida I (2001) Mechanical properties of wood swollen in organic liquids with two or more functional groupes for hydrogen bonding in a molecule. J Wood Sci 47:171–177

    CAS  Article  Google Scholar 

  3. 3.

    Ishimaru Y, Arai K, Mizutani M, Oshima K, Iida I (2001) Physical and mechanical properties of wood after moisture conditioning. J Wood Sci 47:185–191

    CAS  Article  Google Scholar 

  4. 4.

    Furuta Y, Yano H, Kajita H (1995) Thermal-softening properties of water-swollen wood. I. The effect of drying history (in Japanese). Mokuzai Gakkaishi 41:718–721

    Google Scholar 

  5. 5.

    Miyabe H (ed) (1968) In: Japan Society of Polymer Science: hand book of material and moisture [Zairyo to Mizu Handbook] (inJapanese). Kyoritu Shuppan. Tokyo, pp 240–262

    Google Scholar 

  6. 6.

    Ishimaru Y., Minase T (1992) Mechanical properties of wood in various stages of swelling. I. Mechanical and swelling behavior of wood swollen in various organic liquids (in Japanese). Mokuzai Gakkaishi 38:550–555

    CAS  Google Scholar 

  7. 7.

    Tokumoto M (1994) Creep and set of wood in the non-equilibrium states of moisture (in Japanese). Mokuzai Gakkaishi 40:1157–1164

    Google Scholar 

  8. 8.

    Suzuki M, Nakato K, Aikawa K (1965) Frequency dependence of dynamic Young's modulus of wood and its relation to creep (in Japanese). Mokuzai Gakkaishi 11:76–82

    Google Scholar 

  9. 9.

    Onogi S (1973) Principles of rheology (in Japanese), 3rd edn. Maki Shoten, Tokyo, pp 97–102

    Google Scholar 

  10. 10.

    Grossman PUA (1976) Requirement for a model that exhibits mechano-sorptive behavior. Wood Sci Technol 10:163–168

    Article  Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Yutaka Ishimaru.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ishimaru, Y., Oshima, K. & Iida, I. Changes in the mechanical properties of wood during a period of moisture conditioning. J Wood Sci 47, 254–261 (2001). https://doi.org/10.1007/BF00766710

Download citation

Key words

  • Moisture-conditioned wood
  • Modulus of elasticity
  • Modulus of rupture
  • Stress relaxation