Microwave Non-Destructive Testing of Wood and Similar Orthotropic Materials
Microwave Non-Destructive Testing of Wood and Similar Orthotropic Materials
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木材和类似正交各向异性材料的微波无损检测
DOI：
10.1007/s11220-005-0014-z
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
F. Orhan
中科院分区：
文献类型：
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作者：
G. Schajer;F. Orhan
描述了一种无损方法，通过测量穿过材料传输的微波的复杂衰减来估计木材等正交各向异性材料的纤维（纹理）方向、水分密度和干密度。正交各向异性材料中的复衰减具有张量特征，类似于应力和应变等其他张量。相同的变换方程和莫尔圆构造适用于材料轴的旋转。可以根据主衰减来识别散装材料属性，并根据主方向来识别纤维（晶粒）方向。材料的正交各向异性性质增加了可测量的独立电特性的数量，并为数据组合和一致性检查提供了有用的机会。在使用木材样品进行的一系列微波衰减测量中，纹理角度识别的标准误差为 0.9°（总测量范围 =−90° 至 +90°，水分密度为 3.7 kg/m3（总测量范围 = 40–50 kg/m3），干燥木材密度为 16 kg/m3（总测量范围 = 325–625 kg/m3）。
A non-destructive method is described to estimate fiber (grain) direction, moisture density, and dry density of an orthotropic material such as wood, from measurements of the complex attenuation of microwaves transmitted through the material. The complex attenuation in an orthotropic material has a tensor character, similar to other tensor quantities such as stress and strain. The same transformation equations and Mohr’s Circle constructions apply to rotations of material axes. Bulk material properties can be identified from the principal attenuations, and the fiber (grain) direction from the principal directions. The orthotropic nature of the material increases the number of independent electrical properties that can be measured and gives useful opportunities for data combination and consistency checking. In a series of microwave attenuation measurements using wood samples, the standard error for identification of grain angle was 0.9° (total measured range =−90° to +90°, for moisture density 3.7 kg/m3(total measured range = 40–50 kg/m3), and for dry wood density 16 kg/m3(total measured range = 325–625 kg/m3).