A Rapid Method to Assess Viscoelastic and Mechanosorptive Creep in Wood

This study presents an alternative method to measure the viscoelastic and mechanosorptive creep of wood using a dynamic mechanical analyzer (DMA). Measurements were made on sugar maple wood specimens in the radial and tangential directions in different RH conditions. Viscoelastic creep measurements showed that DMA can detect effects of time, RH, load level, and wood direction on wood creep. With the applied stress levels (5, 25, 35, and 45%), wood exhibited linear viscoelastic behavior. DMA also demonstrated its value in measuring mechanosorptive effect. The mechanosorptive effect was observed as RH changed during the loading period, resulting in very high deflections. In both viscoelastic and mechanosorptive creep measurements, creep proved to be greater in the tangential direction than in the radial direction. The results of this study demonstrated that a DMA can be a rapid and accurate tool to predict the time-dependent behavior of wood under load.