木材缺陷与超声检测参数相关性及影响因素

Correlation and Influencing Factors between Wood Defect and Ultrasonic Propagation Parameters

以完好、带有节子和孔洞(椴木、榆木和冷杉)的木材试件为研究对象,通过超声波检测手段,在不同含水率条件下,提取不同缺陷试件的超声检测参数——波速与能量衰减率。结果表明:在同一树种和同一含水率下,节子与孔洞试件超声波能量衰减变化量比波速变化量大;不同缺陷状态下传播速度的分布界限不明显,相反,各种缺陷状态间能量衰减值差别较大。这表明能量衰减在不同缺陷状态的变化最明显,且含水率对能量衰减的影响也相对较小,因此利用能量衰减率作为检测木材缺陷的指标比其他参数更易于检测出木材缺陷。

With the wood specimens of intact,knots and holes from linden,elm and fir,we detected the ultrasonic propagation parameters（ velocity and attenuation coefficient） of milk with different defect specimens at different water contents. The changes in different defect specimens had little effect on the ultrasonic velocity in the same tree species and water contents.The distribution limits of propagation speed was not obvious in different defects,while the attenuation coefficient had larger difference in different defects. The change of attenuation in different defects was the most obvious,and the attenuation was little sensitive to water contents. Therefore,the attenuation coefficient was the better indicator for wood defects.