Effects of temperature and moisture content on selected wood mechanical properties involved in the chipping process
Effects of temperature and moisture content on selected wood mechanical properties involved in the chipping process
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DOI：
10.1007/s00226-014-0673-9
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发表时间：
2014-10
影响因子：
3.4
通讯作者：
R. Hernández;Leandro Passarini;Ahmed Koubaa
中科院分区：
文献类型：
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作者：
R. Hernández;Leandro Passarini;Ahmed Koubaa
评估了温度和水分含量对与切削过程相关的选定机械性能的影响。在碎裂中，涉及机械性能，例如平行于晶粒的剪切、解理和弯曲。从新鲜采伐的黑云杉和香脂冷杉原木中获取匹配的心材和边材样品，以确定所研究的机械性能在 -30 至 20°C 之间（间隔为 10°C）的变化。测量每个样品的水分含量（MC）、基本密度（BD）和年轮宽度（RW）。对于这两种木材，温度对冷冻条件（0°C 以下）下的所有机械性能都有显着影响。这种效应对于边材比对于心材更重要，这可以通过这两种木材之间的 MC 差异来解释。在 0 至 20°C 之间，温度和木材类型对机械性能没有显示出任何显着影响。获得多元回归模型来预测机械性能。这些回归表明 MC 是解释 0°C 以下机械性能的最重要因素。然而，对于 0 °C 及更高的温度，BD 是预测机械性能的主要因素。 RW 不是预测任何机械性能的重要因素。解理是对温度变化最敏感的一种，其次是剪切、断裂模量和弹性模量。这些结果在切削过程中可能非常重要。
The effects of temperature and moisture content on selected mechanical properties associated with the chipping process were evaluated. In chipping, mechanical properties such as shear parallel to the grain, cleavage, and bending are involved. Matched samples of heartwood and sapwood were obtained from freshly harvested logs of black spruce and balsam fir to determine the variation of the studied mechanical properties between −30 and 20 °C, at intervals of 10 °C. Moisture content (MC), basic density (BD), and annual ring width (RW) were measured for each sample. For both wood species, temperature had a significant effect on all mechanical properties under freezing conditions (below 0 °C). This effect was more important for sapwood than for heartwood, which was explained by the difference in MC between these two types of wood. Between 0 and 20 °C, temperature and type of wood did not show any significant effect on the mechanical properties. Multiple regression models were obtained to predict the mechanical properties. These regressions showed that MC was the most important factor to explain the mechanical properties below 0 °C. However, for temperatures of 0 °C and higher, BD was the principal factor to predict the mechanical properties. RW was not a significant factor to predict any mechanical property. Cleavage was the most sensitive one to changes in temperature followed by shear, modulus of rupture, and modulus of elasticity. These results could be of great importance in the chipping process.