ブナ材のクリープと含水率について

The creep of Buna (Fagus crenata Blume) in bending was investigated under the conditions of several relative humidities and the water-saturated condition at temperature 25℃, and the effect of moisture content upon creep or total deformation was discussed being based on the effect of temperature upon them where the two factors, time and temperature, are separable into the form of the product of the two functions which are independent each other in their variables. Such a separation was also found in this case. Thus we obtain the most general equation for creep or total deformations at various moisture contents within the range of the linear reiationship between creep and load :
y(t, u) = FPJ_0(u) ｛1＋f(t)・g(u) ｝
where y is the total deformation as a function of time t and moisture content u; f(t), g(u) functions of t and u, respectively; F form factor; P load; and J_0 compliance at t=0.
This probably means that the creep deformation is essentially determined by the factor t only and the significance of moisture content is multiplying the effect of the former by the latter effect g(u). Since the function f(t) is not linear with t in this equation we cannot draw a master curve for creep. The affection of moisture content upon the creep deformation is greater (g(u) times) than the instantaneous deformation. We think that these are some characteristic properties of creep of wood in comparison with other high polymers.
The function g(u) may be approximateiy repsesented by these expressions :
g(u) = exp (kνu) , 0＜__＿u＜20 (%)
ν = 0.029987,
g(u) = uq , 0＜u＜25 (%)
q = 0.6618.