1996 Volume 45 Issue 4 Pages 376-380
The effect of temperature (20-80°C) on the bending creep of wood during moisture adsorption (7%→16%) and desorption (16%→7%) was investigated by using small beams of buna (Fague crenata Blume) and hinoki (Chamaecyparis obtusa Endl.) wood. The test specimens were 120mm radially, 3mm tangentially and 10mm longitudinally. The span was 100mm and the prescribed bending loads fitting to the test temperature were applied at the center of span. The final equilibrium moisture contents were attained in one step (fast) and in 7-8 steps (slow) by suitable humidity schedules in a testing chamber.
Creep during moisture desorption was not dependent on temperature between 20°C and 80°C. On the other hand, creep during moisture adsorption was dependent not only on temperature but also on time and the range of moisture content. The difference in temperature dependence of creep between the adsorption and desorption period may be explained based on the behaviour of the amorphous region composed of molecular network. Some possible explanations are given in terms of the response of the molecular network structure in the amorphous region during desorption and adsorption.
