Moisture content adjustments for dynamic modulus of elasticity of wood members

作者：Barrett J David^*; Hong Jung Pyo

来源：Wood Science and Technology, 2010, 44(3): 485-495.

DOI：10.1007/s00226-009-0292-z

The influence of moisture content (MC) on the dynamic modulus of elasticity of structural lumber was investigated using transverse vibration testing methods. The flexural rigidity (EI) of a transversely vibrating beam was calculated as the modulus of elasticity (E) multiplied by the moment of inertia (I). The increase in E of lumber due to reduction in moisture content was computed by assuming that the flexural rigidity remains constant with changes in moisture content. Reductions in I due to shrinkage were compensated by the increases in E which led to a proposal for a species-dependent MC adjustment model for modulus of elasticity. The model was validated using 38 mm x 89 mm x 4,290 mm western Canadian Spruce-Pine-Fir dimension lumber evaluated in the "as-received" and "dry" conditions. Results obtained from the species-dependent model agreed closely with those from the E adjustment equation for dimension lumber given in ASTM D 1990. The results show that the ASTM moisture adjustment procedures can be used to adjust dynamic E values for changes in moisture content also.

• 出版日期2010-8