Primary Creep in Douglas-Fir Beams of Commercial Size and Quality
Keywords:
Beams, deflection, relative creep, creepAbstract
Primary creep of nominal 4- x 4-inch Douglas-fir beams of No. 2 grade was measured at four levels of stress, at 12% wood moisture content.
Equations are presented for deflection and relative creep at the four stress levels. Results show relative creep to be nearly independent of stress level, with some evidence that relative creep shows a negative correlation with wood elastic modulus.
References
Cizek, Ludvik. 1961. Long-term strength and theological properties of wood and wood-base materials. Holz Roh-Werkst.19(3):83-85.nClouser, William S. 1959. Creep in small wood beams under constant bending load. Forest Products Laboratory Rep. No. 2150.nFlugge, Wilhelm. 1975. Viscoelasticity, 2nd ed. Springer-Verlag, New York.nGrossman, P. U. A., L. D. Armstrong, and R. S. T. Kingston. 1969. Assessment of research in wood rheology. Wood Sci. Technol.3(4):324-328.nKingston, R. S. T. 1962. Creep, relaxation, and failure of wood. Res. App. in Ind.15(4):164.nKingston, R. S. T., and Armstrong, L. D. 1951. Creep in initially green wooden beams. Division of Forest Products, CSIRO, Melbourne. Aust. J. Appl. Sci.2(1):306-325.nKingston, R. S. T., and L. N. Clarke 1961. Some aspects of the rheological behaviour of wood: I. The effect of stress with particular reference to creep. II. Analysis of creep data by reaction-rate and ther-modynamic methods. Aust. J. Appl. Sci.12(2):211-226, 227-240.nLeicester, R. H. 1971. A rheological model for mechano-sorptive deflection of beams. Wood Sci. Technol.5(3):211-226.nPopov, E. P. 1949. Bending of beams with creep. J. Appl. Physics20(3):251-256.nRantu-Maunus, Alpo. 1975. The viscoelasticity of wood at varying moisture content. Wood Sci. Technol.9(3):189-206.nSAS Institute. 1979. SAS user's guide. Statistical Analysis System Institute, Cary, NC.nSchneiwind, Arno. P. 1967. Creep rupture life of Douglas-fir under cyclic environmental conditions. Wood Sci. Technol.1(4):278-288.nSchneiwind, Arno. P. 1968. Recent progress in the study of rheology of wood. Wood Sci. Technol.2(3):188-206.nSchneiwind, Arno. P. 1973. Further experiments on creep-rupture life under cyclic environmental conditions. Wood Fiber4(4):334-341.nSenft, John F., and S. K. Suddarth. 1971. An analysis of creep-inducing stress in Sitka spruce. Wood Fiber2(4):321-327.nSnedecor, George W. 1956. Statistical methods, 5th ed. Iowa State College Press, Ames, IA.nUgolev, B. N. 1976. General laws of wood deformation and rheological properties of hardwood. Wood Sci. Technol.10:169-181.nU.S. Forest Products Lab. 1974. Wood handbook. USDA, Madison, WI.n
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