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二三の一定周波数のもとで、トドマツ材のE'とE"の温度依存性を、木材細胞膜中の水分の影響との関連において検討した。全乾状態の木材では、いわゆる温度分散が-35℃付近に認められるが、水分を含むと、温度分散の位置はさらに低温側に移動する。しかも、含水率およそ6％までの水分の増加で、温度分散の位置は大きく低温側に移動するが、6％をこえると、その移動は小さくなる。またそれぞれの周波数の対数と、温度分散の位...置における絶対温度の逆数との間には直線関係が存在し、全乾材の直線とくらべて気乾材のそれは、明らかに低温側にずれる。
The dynamic elastic modulus, E', and the loss modulus, E", of wood have been investigated using the results of non-resonance and forced longitudial vibration tests. The tests were done at frequencies of 3.5, 11, 35, and 110 Hz, for various temperatures ranging from about -150°C to +150°C. The test specimens were prepared from Todomatsu-wood (Abies Sachalinensis Mast.), and were conditioned to several moisture contents which varied from almost 0% (oven－dry) to about 18%. Main results obtained from the investigation are as follows: 1) For oven－dried wood sample, the so－called temperature dispersion was observed at about -35°C. This temperature dispersion may be due to the motion of micro segment of wood substances. 2) For wood samples containing moisture, the position of the temperature dispersion shifted to lower temperatures, as compared to oven－dried sample. That is, the position of the temperature dispersion shifted to lower temperatures with increasing moisture content (m.c.) for samples containing below about 6% m.c., but for samples containing more than about 6％ m.c., the shift in the position of the temperature dispersion became smaller. 3) The absolute temperatures, T, at which the temperature dispersions were observed, were obtained for given frequencies, f, and a plot of log f against 1/T gave a straight line. The straight line for wood sample containing moisture shifted apparently to lower temperatures compared to that for oven-dried wood sample; however, there was no remarkable difference in the slopes between both the straight lines.show more
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木材学会誌20(8)