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林业科学 ›› 2008, Vol. 44 ›› Issue (5): 115-121.doi: 10.11707/j.1001-7488.20080522

• 论文 • 上一篇    下一篇

传感器的数量与分布对应力波检测原木缺陷效果的影响

王立海1.2 徐华东1 闫在兴1 吕建雄2 杨学春1 周次林1   

  1. (1.东北林业大学工程技术学院 哈尔滨150040; 2.中国林业科学研究院木材工业研究所 北京100091)
  • 收稿日期:2006-11-15 修回日期:1900-01-01 出版日期:2008-05-25 发布日期:2015-04-22

Effects of Sensor Quantity and Planar Distribution on Testing Results of Log Defects Based on Stress Wave

Wang Lihai1.2,Xu Huadong1,Yan Zaixing1,Lü Jianxiong2,Yang Xuechun1,Zhou Cilin1

  

  1. (1.College of Engineering & Technology,Northeast Forestry University Harbin 150040;2.Research Institute of Wood Industry,CAF Beijing 100091)
  • Received:2006-11-15 Revised:1900-01-01 Online:2008-05-25 Published:2015-04-22

摘要:

对取自黑龙江省带岭林区4个主要树种的10个含有2种缺陷的原木样本进行测试和分析。结果表明:当原木直径在20~40 cm范围内时,若需对原木缺陷进行精确测量,要求图像拟合度接近90%和误差率在0.1左右时,至少需12个传感器才能满足要求; 当不需要对原木缺陷进行精确测量,只需确定缺陷的大致位置时,宜选用10个传感器进行测量; 当仅仅需要判断木是否存在缺陷时,选用6个传感器就能满足要求。本文通过平面几何学和统计学的基本方法研究了传感器测试平面内的分布对可测最小缺陷面积比的影响,从而找到影响因素并得出结论:在测试工作中通过目测均匀放置传感器即可以达到所要求的测试效果。

关键词: 原木无损检测, 应力波, 传感器数量, 测试平面分布, 检测效果

Abstract:

The stress wave nondestructive testing (NDT) technique is developed quickly in the recent years. How to determine the appropriate number of sensors and allocate the sensors in order to improve the testing efficiency and accuracy is one of the common issues. Ten samples of four tree species with two kinds of defects collected from Heilongjiang Province are selected for the study. The results show that for trees with diameter ranging from 20~40 cm,at least 12 sensors are needed to ensure a high testing accuracy of roughly 90% of fitness and 0.1 of error rate. Ten sensors are suitable to tell the possible locations of defects and 6 sensors are sufficient to decide whether there are defects. With plane geometry and statistic analysis this study further discusses the impact of planar distribution of sensors on the percentage of minimum detectable defect size (MDDS). The mathematical model developed in this study indicates the affecting factors and basic rules of the sensor planar allocation on testing results. Finally,it is concluded that a satisfied testing result could be achieved only if the sensors are distributed in uniformity by eyeballing.

Key words: wood nondestructive testing, stress wave, sensor quantity, planar distribution, testing results