Adjusting modulus of elasticity of lumber for changes in temperature
Adjusting modulus of elasticity of lumber for changes in temperature
复制标题
根据温度变化调整木材的弹性模量
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
W. Nelson
中科院分区：
文献类型：
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作者：
D. Green;J. Evans;J. Logan;W. Nelson
本研究评估了温度在150°至-15 ° F（66°至26°C）范围内对绿色和干燥标称2 x 4英寸（标准38 x 89 mm）结构木材的弯曲弹性模量（莫伊）的直接影响。对于含水量（MC）为12%的木材，使用线性关系将莫伊的增加与温度的降低联系起来。对于绿色材，莫伊也随着温度的降低而增加。开发分段线性回归来描述温度从150°至0°F（66°至-18 ° C）时莫伊的变化。在32°F（0°C）以下，该关系的斜率比在该温度以上更陡。绿色木材的实际含水量不是高于0°F（-18 ° C）的系数。在0°F以下，随着温度降低，莫伊的增加是实际绿色MC和温度的函数。我们讨论的因素，导致这种行为在绿色木材在低温和使用的经验模型描述的MOE-温度的关系作为冻结绿色木材的MC的函数。该模型被认为是独立的软木品种和木材等级。相对于100°F（38°C）时的莫伊，本研究结果支持国家设计规范（1）中给出的C t系数。
This study evaluated the immediate effect of temperature on flexural modulus of elasticity (MOE) of green and dry nominal 2- by 4-inch (standard 38- by 89-mm) structural lumber at temperatures ranging from 150° to -15°F (66° to 26°C). For lumber at 12 percent moisture content (MC), a linear relationship was used to relate the increase in MOE to the decrease in temperature. For green lumber, MOE also increased with decreasing temperature. A segmented linear regression was developed to describe the change in MOE for temperatures from 150° to 0°F (66° to -18°C). The slope of this relationship was steeper below 32°F (0°C) than above this temperature. The actual MC of green lumber was not a factor above 0°F (-18°C). Below 0°F, the increase in MOE with decreasing temperature was a function of both actual green MC and temperature. We discuss factors that cause this behavior in green wood at low temperatures and the use of an empirical model for describing the MOE-temperature relationship as a function of MC for frozen green lumber. The model is believed to be independent of softwood species and lumber grade. Relative to MOE at 100°F (38°C), results of this research support the C t factors given in the National Design Specifications (1).