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Bending creep behavior of wood under cyclic moisture changes

Abstract

This study examined the bending creep behavior in the longitudinal direction of six species under cyclic moisture content (MC) changes. For each species, tests were made at 20°C with five cyclic relative humidity changes between 65% and 95%, beginning from moisture adsorption. A load corresponding to 25% of short-term breaking load of the species was applied to the radial section of each specimen with four-point bending. The effect of MC change on instantaneous compliance was also investigated under the same condition. The quantitative relation between mechano-sorptive (MS) compliance and MC change was examined, and the material parameter KM for the relation in specific sorption was determined. Results indicated that the total compliance in the six species with different behavior increases with sorption time. As an integral part of total compliance, instantaneous compliance changes linearly with MC and influences to a greater or lesser extent the total compliance behavior. In general, with increasing MC change, the MS compliance linearly increases during the first adsorption and all desorption and decreases slightly during subsequent adsorption. The material parameterK M varies markedly not only with species but also with specific sorption. The first adsorption causes the largest deformation, followed by desorption.

References

  1. 1.

    Armstrong LD, Kingston RT (1962) The effect of moisture content changes on the deformation of wood under stress. Aust J Appl Sci 13:257–276

  2. 2.

    Schniewind AP (1968) Recent progress in the study of rheology of wood. Wood Sci Technol 2:188–206

  3. 3.

    Armstrong LD (1972) Deformation of wood in compression during moisture movement. Wood Sci 5:81–86

  4. 4.

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

  5. 5.

    Hearman RFS, Paton JM (1964) Moisture changes and creep of wood. For Prod J 14:357–359

  6. 6.

    Rice RW, Youngs RL (1990) The mechanism and development of creep during drying of red oak. Holz Roh Werkstoff 48:73–79

  7. 7.

    Wu Q, Milota MR (1995) Rheological behavior of Douglas-fir at elevated temperature. Wood Fiber Sci 3:285–295

  8. 8.

    Wu Q, Milota MR (1996) Mechano-sorptive deformation of Douglas-fir specimens under tangential tensile stress during moisture adsorption. Wood Fiber Sci 1:128–132

  9. 9.

    Norimoto M, Gril J (1989) Wood bending using microwave heating. J. Microwave Power Electromag Energy 24:203–212

  10. 10.

    Iida I, Norimoto M, Imamura Y (1983) Wood bending utilizing microwave heating hygrothermal recovery of bentwood in the direction perpendicular to grain (in Japanese). Wood Res 17:99–111

  11. 11.

    Nakano T (1996) A theoretical description of creep behavior during water desorption. Holzforschung 50:49–54

  12. 12.

    Hunt DG (1984) Creep trajectories for beech during moisture changes under load. J Mater Sci 19:1456–1467

  13. 13.

    Leicester RH (1971) A theological model for mechano-sorptive deflections of beams. Wood Sci Technol 5:211–220

  14. 14.

    Ranta-Maunus A (1975) The viscoelasticity of wood at varying moisture content. Wood Sci Technol 9:189–205

  15. 15.

    Gerhards CC (1982) Effect of moisture content and temperature on the mechanical properties of wood: an analysis of immediate effect. Wood Fiber 14(1):4–36

  16. 16.

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

  17. 17.

    Hunt DG (1986) The mechano-sorptive creep susceptibility of two softwoods and its relation to some other materials properties. J Mater Sci 21:2088–2096

  18. 18.

    Armstrong LD, Christensen GN (1961) Influence of moisture change on deformation of wood under stress. Nature 191:869–870

  19. 19.

    Armstrong LD, Kingston RT (1960) Effect of moisture change on creep in wood. Nature 185:862–863

  20. 20.

    Lu W, Erickson RW (1994) The effect of directed diffusion on the mechano-sorptive creep of small redwood beam. For Prod J 44(1):8–14

  21. 21.

    Erins PV, Cinite V, Jakobson M (1976) Wood as a crosslinked, multicomponent polymer system. In: Applied Polymer Symposium No. 28. ACS, pp 1117-1138

  22. 22.

    Hunt DG (1997) Dimensional changes and creep of spruce, and consequent model requirements. Wood Sci Technol 31:3–16

  23. 23.

    Nakano T (1996) Viscosity and entropy change in creep during water desorption for wood. Wood Sci Technol 30:117–125

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Correspondence to Yaguang Zhou.

Additional information

This paper was presented at the 48th annual meeting of the Japan Wood Research Society in Shizuoka, Japan. April 1998

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Zhou, Y., Fushitani, M., Kubo, T. et al. Bending creep behavior of wood under cyclic moisture changes. J Wood Sci 45, 113–119 (1999). https://doi.org/10.1007/BF01192327

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Key words

  • Creep
  • Cyclic moisture sorption
  • Bending stress
  • Species