Influence of Moisture Sorption on the Strength of Sugar Maple Wood in Tangential Tension


  • Marcel Goulet
  • Roger Hernández


Moisture sorption, moisture changes, mechanical properties, compliance coefficient, ultimate tensile stress, fiber-saturation point, sugar maple


This research confirms that, at a given equilibrium moisture content, the strength perpendicular to the grain is less after desorption than after adsorption. This behavior, called second-order effects of moisture sorption, has been established for sugar maple wood in tangential tension. For the compliance coefficient s33, these effects only halve those measured in radial compression (s22)- Also, it is shown that second-order effects could be present, though to a lesser extent, up to failure. Near the oven-dry condition, some internal tensions were responsible for a decrease of the ultimate tensile stress in the adsorption state. A subsequent remoisturing eliminated those tensions, seemingly built up during the preliminary drying of samples. Finally, near the fiber-saturation point, a loss of bound water may take place in the presence of free water and thus affect significantly the strength of wood across its grain.


Bodig, J., and B. A. Jayne. 1982. Mechanics of wood and wood composites. Van Nostrand Reinhold, New York.nDjolani, B. 1970. Hystérèse et effets de second ordre de la sorption d'humidité dans le bois aux températures de 5°, 21°, 35° et 50°C. Note de recherches N° 8, Département d'exploitation et utilisation des bois, Université Laval, Québec.nFortin, Y. 1979. Moisture content-matric potential relationship and water flow properties of wood at high moisture contents. Ph.D. thesis, University of British Columbia, Vancouver, BC.nGoulet, M. 1968. Phénomènes de second ordre de la sorption d'humidité dans le bois au terme d'un conditionnement de trois mois à température normale. Seconde partie: Essais du bois d'érable à sucre en compression radiale. Note de recherches N° 3, Département d'exploitation et utilisation des bois, Université Laval, Québec.nGoulet, M., and Y. Fortin. 1975. Mesures du gonflement de l'érable à sucre au cours d'un cycle de sorption d'humidité à 21°C. Note de recherches N° 12, Département d'exploitation et utilisation des bois, Université Laval, Québec.nHart, C. A. 1984. Relative humidity, EMC, and collapse shrinkage in wood. Forest Prod. J. 34(11/12):45-54.nHiggins, N. C. 1957. The equilibrium moisture content relative humidity relationship of selected native and foreign woods. Forest Prod. J. 7(10):371-377.nLaforest, P. 1981. Relation entre l'état de sorption et les déformations élastiques du bois d'érable à sucre en traction et en compression de fil. D.Sc. thesis, Département d'exploitation et utilisation des bois, Université Laval, Québec.nLaforest, P., and A. Plamondon. 1976. Effet d'une pression hydrostatique élevée sur les membranes du bois. Seconde partie: proprietés hygroscopiques et mécaniques du bois. Note de recherches N° 15, Département d'exploitation et utilisation des bois, Université Laval, Québec.nSeifert, J. 1972. Zur Sorption und Quellung von Holz und Holzwerkstoffen. Zweite Mitteilung: Das Quellungsverhalten von Holz und Holzwerkstoffen. Holz Roh-Werkst. 30(8):294-303.nSiimes, F. E. 1967. The effect of specific gravity, moisture content, temperature, and heating time on the tension and compression strength and elasticity properties perpendicular to the grain of Finnish pine, spruce and birch wood and the significance of these factors on the checking of timber at kiln drying. State Inst. Tech. Res., Publ. 84, Helsinki, Finland.nSkaar, C. 1988. Wood-water relations. Springer-Verlag, New York.nSliker, A. 1978. Strain as a function of stress, stress rate, and time at 90° to the grain in sugar pine. Wood Sci. 10(4):208-219.nSpalt, H. A. 1958. The fundamentals of water vapor sorption by wood. Forest Prod. J. 8(10):288-295.nStevens, W. C. 1963. The transverse shrinkage of wood. Forest Prod. J. 13(9):386-389.nSuchsland, O. 1980. Determination of sorption isotherms in minidesiccators. Wood Sci. 12(4):214-217.n






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