Modeling temperature effect on dynamic modulus of elasticity of red pine (Pinus resinosa) in frozen and non-frozen states

The response of dynamic and static modulus of elasticity (MOEdyn and MOEsta) of red pine small clear wood (25.4x25.4x407 mm(3)) within the temperature range -40 to 40 degrees C has been investigated. The moisture content (MC) of the specimens ranged from 0 to 118%. The MOEdyn was calculated based on measured ultrasonic velocity (V) and wood density. The MOEsta was measured by static bending tests in a climate chamber between -40 and 40 degrees C. The results indicate that both MOEdyn and MOEsta were affected by temperature and the MC. Above freezing point, MOE decreased linearly at a slow rate with increasing temperature. Below freezing point, MOE increased at a rapid rate with decreasing temperature. The MC-level had a significant effect on the MOE-temperature relationships. Temperature effect was much more significant in green wood than in dry wood. Analytical models were developed to predict the change of MOEdyn relative to that at 20 degrees C in the case of acoustic measurements under different temperature conditions.