Young's Modulus Parallel to the Grain in Wood as A Function of Strain Rate, Stress Level and Mode of Loading


  • Alan Sliker


Tsuga heterophylla, Quercus sp., Pseudotsuga menziesii, dynamic tests, static tests, bending tests, compression tests, tension tests


Moduli of elasticity were determined parallel to the grain in wood specimens using dynamic flexural tests, static tensile tests, and static compression tests. in the static tests the specimens were repetitively loaded at different strain rates below their proportional limits. Stress rate and strain rate data were taken at discrete stress levels. Species used were red oak, Douglas-fir, and western hemlock.

Stress rate plotted as a linear function of strain rate with zero intercept. The slopes of the plots were Young's moduli. For the majority of specimens, there were no significant differences between Young's moduli in tension and Young's moduli in compression. There were also no indications that Young's moduli were either a function of stress level or strain rate. Dynamic flexural moduli uncorrected for shear deflection averaged 3% less than static tensile moduli.


Bell, E. R., E. C. Peck and N. T. Krueger. 1954. Modulus of elasticity of wood determined by dynamic methods. U.S. Forest Service FPL Report 1977, Madison, Wisconsin.nEthington, R. L., and R. L. Youngs. 1965. Some observations on perpendicular-to-grain rheology of northern red oak (Quercus rubra L.). Holz Roh-Werkst. 23(5):196-201.nFreese, F. 1964. Linear regression methods for forest research. U.S. Forest Service FPL Research Paper 17, Madison, Wisconsin.nJames, W. L. 1968. Static and dynamic strength and elastic properties of ponderosa and loblolly pine. Wood Sci. 1(1):15-22.nKing, E. G., Jr. 1957. Creep and other strain behavior of wood in tension parallel to the grain. For. Prod. J. 7(10):324-330.nKing, E. G., Jr. 1961. Time dependent strain behavior of wood in tension parallel to the grain. For. Prod. J. 11(3):156-165.nKitazawa, G. 1952. Young's modulus of elasticity by dynamic measurements. For. Prod. J. 2(5):228-231.nOkuyama, T., and I. Asano. 1970. Effect of strain rate on mechanical properties of wood. I. on the influence of strain rate to compressive properties parallel to the grain of wood. J. Jap. Wood Res. Soc. 16(1):15-18.nOkuyama, T., K. Tsuzuki, and I. Asano. 1970. Effect of strain rate on mechanical properties of wood. II. On the empirical equation of stress/strain relation in compression. J. Jap. Wood Res. Soc. 16(1):20-25.nSliker, A. 1972. Measuring Poisson's ratios in wood. Exp. Mech. 12(5):239-242.nSmith, T. L., and R. A. Dickie. 1970. Effect of finite extensibility on the viscoelastic properties of styrene-butadiene rubber vulcanizate in simple tensile deformation up to rupture. Rubber Chem. Technol. 43(4):714-734.n






Research Contributions