スギのクリープと温度について

Abstract

We studied on the creep of Sugi (Cryptomeria japonica D. Don) and examined the relationship between the creep and the temperature.
The constant load within the proportional limit was applied with a balance to the end of a cantilever(0.2×1.0×12.0cm) in the distillated water. The temperatures of the water were 0.5°, 20°, 40°, 60°, 80℃ (±0.5°-1.0℃). The deflection of the cantilever was measured by comparator during 200 minutes.
Then in each specimen the ratio
ε = (y-y_0)/(y_0)
y : deflection at time t
y_0 : deflection at time
0.5 min
was nearly constant at the same temperature. These ratios at different temperatures are essentially equal except a constant η :
logε = g(ζ) + η,ζ = log t
where g(ζ) is a function of logt. The constant η is linear to temperature (cf. Fig. 7). And g(ζ) is approximately a linear function of ζ (=log t) within the range of our measurements, although this approximation is rough (cf. Fig.6). Then the time-temperature superposition principle is concluded like a generalized voigt model, of which retardation times τ are decreasing with increasing temperature and represented by τ/a_θ(a_θ＞1, suffix θ is the difference from the standard temperature).