Deformation Detection Method in a Circular Metallic Tube using Microwaves

Abstract

Metallic tubes used in factories and industrial plants may be deformed as a result of long term use and other natural causes. Thus far, various non-destructive inspection (NDI) methods have been proposed to prevent accidents caused by deformation. However, the drawback of these conventional methods is that they take a longer time for very long tubes. In this paper, we propose a new detection method using electromagnetic wave propagation. In this method, metallic tubes are regarded as waveguides and we can determine the existence of deformations by propagating electromagnetic waves. To verify this method, we performed numerical experiments to estimate by propagation mode in a circular waveguide and to detect a deformation by the fluctuation in the reflection coefficient. After that, we performed measuments to verify the validity of the numerical experiments. We found that the proposed method is effective for detecting a deformation and for estimating its location and angle.