Kazys R, Demcenko A, Zukauskas E, Mazeika L
Ultrasound Institute of Kaunas University of Technology, Studentu str. 50, Kaunas LT-51368, Lithuania.
Ultrasonics. 2006 Dec 22;44 Suppl 1:e819-22. doi: 10.1016/j.ultras.2006.05.112. Epub 2006 Jun 6.
Air-coupled ultrasonics is fine alternative for the immersion testing technique. Usually a through transmission and a pitch-catch arrangement of ultrasonic transducers are used. The pitch-catch arrangement is very attractive for non-destructive testing and evaluation of materials, because it allows one-side access to the object. However, this technique has several disadvantages. It is sensitive to specularly reflected and edge waves. A spatial resolution depends on a distance between the transducers. A new method for detection and visualisation of inhomogeneities in composite materials using one-side access air-coupled ultrasonic measurement technique is described. Numerical predictions of Lamb wave interaction with a defect in a composite material are carried out and the interaction mechanism is explained. Experimental measurements are carried out with different arrangements of the transducers. The proposed method enables detect delamination and impact type defects in honeycomb materials.
空气耦合超声是浸入式检测技术的良好替代方法。通常使用超声换能器的穿透传输和斜探头布置。斜探头布置对于材料的无损检测和评估非常有吸引力，因为它允许从一侧接近检测对象。然而，该技术存在几个缺点。它对镜面反射波和边缘波敏感。空间分辨率取决于换能器之间的距离。本文描述了一种使用单侧接入空气耦合超声测量技术检测和可视化复合材料中不均匀性的新方法。对复合材料中兰姆波与缺陷的相互作用进行了数值预测，并解释了相互作用机制。使用不同的换能器布置进行了实验测量。所提出的方法能够检测蜂窝材料中的分层和冲击型缺陷。
