The Viscoelastic Behavior Of Perpendicular To Grain Of Birch Plasticized By Moisture

This study was aimed at investigating the creep behavior,stress relaxation behavior,and dynamic v iscoelasticity of birch plasticized by moisture and temperature,deepening theoretical study of wood visc oelasticity,and providing a scientific basis for its application.Creep and stress relaxation behavior were both examined at six constant MCs(0%,6%,12%,18%,24%,>30%)and 11 temperatures ranging fro m 5℃to 95 ℃(5℃,15℃,25℃,35℃,45℃,55℃,65℃,75℃,85℃,95℃).Experiments were conducted using Dynamic Mechanical Analyzer with its Relative Humidity Control(Q800).1.The total compliance,instantaneous compliance,and creep compliance of specimens at all MCs speci mens increased at higher temperatures,but samples with higher MCs were affected more pronounced,n early an order of magnitude greater.Creep compliance of all samples increased dramatically at certain te mperatures.2.The total compliance,instantaneous compliance,and creep compliance were affected greatly by the M C of specimens and increased significantly with the increase in MC.The initial relaxation and final rela xation decreased with the increase in MC.The effect of temperature was greater with the increasing MC.3.At higher temperature and MC,a complex interaction of temperature and MC on the total compliance,instantaneous compliance,creep compliance and relaxation modulus was found.4.At certain temperature and MC,30-min creep compliance was higher than the corresponding instantan eous compliance.5.The storage modulus decreased with the increase in temperature and MC.Greater reduction was found at higher temperature and MC.The loss factor decreased with the decrease in MC.