Elastic Constants for Hardwoods Measured from Plate and Tension Tests


  • Alan Sliker
  • Ying Yu


Density, hardwoods, plate twisting tests, Poisson's ratio, shear modulus, tensile tests, Young's modulus


Measurements of shear moduli GLR and GLT, Young's moduli EL, ER, and ET, and Poisson's ratios vLT and vLR were made at approximately 12% moisture content from material cut from 18 eastern hardwood logs. Shear moduli calculated from off-axis tension tests with angle of load to the L-axis of 20° were slightly larger than those from plate tests. ER values determined from off-axis tensile tests closely approximated those determined from tensile tests in the R direction. Poisson's ratios for basswood, cottonwood, and soft maple were negative (strains parallel and perpendicular to the load direction were both positive) in the LT plane for loadings at 20° to the L direction. Some significant correlations were found between the reciprocals of elastic constants and the reciprocals of density at test, also between the reciprocals of shear moduli and the reciprocals of Young's moduli ER and ET. There was less variability in measurements made in the LR plane than in the LT plane.


American Society for Testing and Materials. 1989. Standard method of test for shear modulus of wood. ASTM D3044-76, Philadelphia, PA.nBodig, J., and J. R. Goodman. 1973. Prediction of elastic parameters for wood. Wood Sci. 5(4):249-264.nEbrahimi, G., and A. Sliker. 1981. Measurement of shear modulus in wood by a tension test. Wood Science 13(3):171-176.nGreszczuk, L. B. 1966. New test technique for shear modulus and other elastic constants of filamentary composites. Douglas Paper No. 3670. Douglas Aircraft Co. Inc., Santa Monica, CA. (Available from National Technical Information Service, Springfield, VA.) 25 pp.nGreszczuk, L. B. 1969. Shear modulus determination of isotropic and composite materials. In Composite materials: Testing and design. ASTM STP 460.nGuitard, D. 1987. Mecanique du materiau bois et composites. Collection nabla. C.E.P.A.D.U.E.S. Editions, Toulouse. 220 pp.nGuitard, D., and F. E. Amri. 1987. Modeles previsionnels de compartment elastique tridimensionnel pour les bois feuillus et les bois resineux. Ann. Sci. For. 44(3):335-358.nKellogg, R. M., and G. Ifju. 1962. Influence of specific gravity and certain other factors on the tensile properties of wood. Forest Prod. J. 12(10):463-470.nPerry, C. C., and H. R. Lissner. 1962. The strain gage primer. McGraw-Hill, New York. 332 pp.nSchuldt, J. P. 1972. Unified testing procedure for determining the elastic parameters of wood. Ph.D. thesis, Colorado State University, Fort Collins, CO. 200 pp.nSliker, A. 1967. Making bonded wire electrical resistance strain gages for use on wood. Forest Prod. J. 17(4): 53-55.nSliker, A. 1989. Measurement of the smaller Poisson's ratios and related compliances for wood. Wood Fiber Sci. 21(3):252-262.nStavsky, Y., and N. J. Hoff. 1969, Mechanics of composite structures. Pages 5-59 in A. G. H. Dietz, ed. Engineering laminates. MIT Press, Cambridge, MA. 328 Pp.nWeigel, T. G. 1991. Non-shear compliances and elastic constants measured for the wood of eight hardwood trees, M.S. thesis, Michigan State University, E. Lansing, MI. 91 pp.nYu, Y. 1990. Non-shear compliances and elastic constants measured for nine hardwood trees. M.S. thesis, Michigan State University, E. Lansing, MI. 79 pp.nZhang, W., and A. Sliker. 1991. Measuring shear moduli in wood with small tension and compression samples. Wood Fiber Sci. 23(1):58-68.n






Research Contributions