基于超声导波技术对弯管中缺陷检测的实验研究

Experimental Study on Defect Detection in Curved Pipes Using Ultrasonic Guided Waves Technique

利用超声导波技术在弯管中进行了缺陷检测的实验研究。利用周向均布的长度伸缩型压电陶瓷片激励特定频率的纵向模态L(0,2),对90°弯管中的人工周向缺陷和结构缺陷等进行了检测,分析了周向缺陷尺寸的变化对缺陷回波和端面回波幅值大小的影响。对弯管中同时存在多个缺陷的情况进行了研究。实验结果表明,超声导波检测技术可以用于弯管中不同部位和不同类型的缺陷检测,这为利用超声导波对更加复杂的管道系统中缺陷检测作了有益探索。

Experimental defect detections in curved pipes was carried out by using ultrasonic guided wave technique. Different kinds of defects including artificial circumferential defects and structural defects were detected using longitudinal mode L（0,2） at certain frequencies excited by lengthexpanding and contracting piezoelectric elements distributed uniformly along circumferential direction in 90° curved pipes. Effects of circumferential defect dimensional variations on waveform amplitudes reflected from the defects and the ends were analyzed. Multi-defect detection in curved pipe was studied as well. Experimental results show that ultrasonic guided wave inspection technique can be used to detect defects with different positions and types in curved pipes. Useful exploration is done to detect defects in more complicated pipe system using ultrasonic guided waves.