小叶杨立木横断面的超声波传播速度

Ultrasonic Wave Propagation Velocity in Cross Section of Simon Poplar Standing Trees

为对立木进行无损检测,探索了超声波在立木内的传播特性及影响因子。以小叶杨(Populus simonii)立木为研究对象,采用针式阻抗仪对30棵样本立木内部缺陷状况进行了初步估计,利用RSM-SYS5超声仪测试了超声波在立木内部的传播速度,分别统计了健康和含缺陷立木内的超声波传播速度,并对缺陷大小与传播速度之间的关系进行了回归分析。分析结果表明:当直径为30～55cm时,超声波在小叶杨健康样本立木中径向传播速度为1000～1616.766m/s,并且绝大多数大于1000m/s;小叶杨立木内部存在缺陷时,超声波径向传播速度均小于1000m/s。立木缺陷对超声波在小叶杨立木内的径向传播速度有较为显著的影响,缺陷大小与径向传播速度呈显著负相关,相关系数R2=0.887。

Propagation characteristics and influence factors of ultrasonic wave spreading in standing trees were studied in order to carry out non-destructive testing of standing trees. Resistograph was employed to test 30 samples of simon poplar （Populus simonii） standing trees to give a preliminary estimate of the internal defects in the samples. Meanwhile,RSM-SYS5 ultrasonic device was also used to test the ultrasonic propagation velocity in the standing trees. A regression analysis of relationship between the size of the defects and the ultrasonic propagation velocity was made in terms of the statistical values of ultrasonic propagation velocity in the healthy trees and in the standing trees with defects. Results show that,when the diameter of sample trees is between 30cm and 55cm,the radial velocity of ultrasonic spreading in the healthy standing trees is higher than 1000m/s,ranging from 1000m/s to 1616.766m/s; however,when there are defects in the simon poplar standing trees,the ultrasonic radial velocity is lower than 1000m/s. The defects in standing trees have a significant influence on the radial propagation velocity of ultrasonic wave spreading in simon poplar standing trees,and defect size is significantly negatively correlated with radial velocity with a correlation coefficient of 0.887.