Mechanosorptive Creep of Hemlock under Conventional Drying: I. The Determination of Free Shrinkage Strain |
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Authors: | Jian-Feng Zhan Stavros Avramidis |
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Affiliation: | 1. College of Material Science and Engineering , Northeast Forestry University , Harbin, P.R. China;2. Department of Wood Science , University of British Columbia , Vancouver, British Columbia, Canada zhanjianfeng2002@yahoo.com.cn;4. Department of Wood Science , University of British Columbia , Vancouver, British Columbia, Canada |
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Abstract: | The dynamic free shrinkage behavior of Western hemlock (Tsuga heterophylla) was investigated in order to provide the theoretical basis for the determination of drying mechanosoptive creep mechanism. Small specimens taken from five distinct positions within a log were dried at three constant temperatures (40, 60, and 80°C) and stepwise decreasing relative humidity conditions and their free shrinkage strain S in the tangential and radial directions was determined. The anisotropic shrinkage ratios G were also calculated and analyzed as functions of moisture content and temperature. The influential mechanism of the drying temperature, moisture range, and specimen position on the free shrinkage behavior was revealed. Two different function types were chosen to simulate the relationship between the free shrinkage strain and its variables (temperature, moisture, wood positions) for the specified moisture ranges. |
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Keywords: | Anisotropic shrinkage Free shrinkage strain Mechanosorptive creep strain Wood |
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