Elastic Constants for Hardwoods Measured from Plate and Tension Tests
Keywords:Density, hardwoods, plate twisting tests, Poisson's ratio, shear modulus, tensile tests, Young's modulus
AbstractMeasurements 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.
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