不同数量传感器下云杉模拟缺陷材应力波成像规律探讨

Research on Stress Wave Tomography of Spruce Logs with Artificial Defects under Different Number Sensors

以云杉原木圆盘为对象,研究不同面积、不同轮廓形状的空洞缺陷及用不同数量传感器情况时应力波成像技术检测缺陷图像与实际缺陷的关系。结果表明:应力波成像系统可以直观显示木材内部缺陷,其检测精度与空洞等实际缺陷面积和被测木材的截面积比率、使用传感器数量及空洞等缺陷轮廓形状有关;当空洞实际面积与被测木材截面积比从1.6%上升到25.0%时,应力波成像系统显示缺陷图像面积与实际缺陷面积相对误差从22.6%下降到9.7%;成像用传感器数量在6～24个之间时,应力波成像系统均能显示空洞等缺陷的存在,但成像用传感器的数量会影响检测精度;缺陷轮廓形状对应力波成像有一定影响,缺陷面积一定时,狭长形缺陷容易被检出,近圆形缺陷检测相对误差小。

In order to raise the precision of stress wave imaging technology（SWIT）,under the conditions of different area and outline of simulated cavity defects in timber discs of spruce,different number of used sensors,the relationship between imaging graph defects and real defects is studied.The result shows：SWIT can display graph of defects,the precision of imaging graph relates to rate of real defect area and area of the tested wood cross section,the number of used sensors and outline shape of the defects.When the rate rises from 1.6% to 25.0%,the relative error of graph defect area and real defect area drops from 22.6% to 9.7%.When the number of used sensors is from 6 to 24,the graph of SWIT can show the existence of real defect.But the number of sensors used influences the precision of SWIT.Outline shape of defects has certain effect on detection of defects.Under the condition of the same defect area,the defects of long and narrow shape are easy to be shown by graph.The relation error of defect area of suborbicular shape is smaller than that of long and narrow shape.