Non-contact metallic inspection by using electromagnetic transfer function

工厂和工业计划中使用的金属管可能会因长期使用和其他自然原因而变形。提出了一种利用电磁波传递函数进行无损检测的新方法。在新方法中，将金属管视为圆形波导，通过管内电磁波的传播来检测管子上的变形。通过测量管道的传递函数(S参数S11)，可以通过改变传递函数来检测管道内部的变形。为了验证该方法，进行了数值和实际实验。作为它们的结果，可以检测到放置在管内的小金属片(尺寸：5 mm×2 mm)。这种新的检测方法可以应用于换热器等复杂形状的多弯管。本文的研究成果为金属管的无损检测提供了新的思路。

Metallic tubes used in factories and industrial plans may be deformed as a results of long term use and other natural causes. In this research, a new non-destructive inspection method by using electromagnetic wave transfer functions is developed. In the new method, metallic tubes are regarded as a circular waveguide, and deformation on the tubes can be detected by electromagnetic wave propagation inside the tube. Measuring the transfer functions (S parameter S11) through the tubes, deformations inside the tubes can be detected by changing the transfer functions.To verify this method, numerical and actual experiments were performed. As the results of them, small metallic piece (size: 5mmx2mm) placed inside the tube can be detected. This new detection method can be applied to complex shape tube with many bends, e.g. heat exchanger. New non-destructive inspection for metallic tubes is achieved by the results of this research.