테라헤르츠파를 이용한 허니컴샌드위치 복합재 패널의 FFT 스캔이미지 비파괴탐상기법

Abstract

In recent years, the importance of terahertz waves (T-ray) has been recognized for detecting defects. With the characterization of Fiber reinforced plastics (FRP) composites the T-ray techniques have been applied. The present study deals with THz scan images of honeycomb sandwich composite panels using a refractive index (n) and electrical conductivity of glass fiber embedded epoxy matrix composites and carbon fiber reinforced plastics (CFRP) skin. A method of detection of FRP composites with impact damage is presented and also aluminum wires could be detected when woven carbon fibers are twisted with conductivity. Thus, a level of transmitted power of THz waves in CFRP composites was compared with that of glass fiber composites quantitatively on the basis of electric field (E-field) in the fiber direction to evaluate a level of transmission of THz according to frequency bandwidth. Based on the T-ray characteristics, a FFT scan image method is proposed, which could detect impact damage on the honeycomb sandwich panels and also a test valid region of THz waves is evaluated for detecting aluminum wires according to carbon fiber orientation when the aluminum wires were inserted with woven carbon fibers on the surface of honeycomb sandwich panels.