# 광섬유 브래그 격자 센서를 이용한 구조물의 모드 형상 측정

• 구본용 (한국과학기술원 항공우주공학과) ;
• 류치영 (한국과학기술원 항공우주공학과) ;
• 홍창선 (한국과학기술원 항공우주공학과)
• Published : 2000.04.01

#### Abstract

Fiber Bra99 grating (FBG) sensor, one of the fiber optic sensor (FOS) offers lots of advantages for structural health monitoring due to its multiplexing capability. Also, it is proper to measure the structural vibration with no mass concentration effect. In this paper, we constructed two sensor arrays composed of 9 FBG sensors for the vibration and mode sensing of a composites beam. For an accurate measurement of wavelength shift, a signal processing board with an electric circuit based on time-interval counting was developed. This sensor system showed a good resolution of dynamic strain (<10${\mu}{\varepsilon}$). Using this sensor system, dynamic strains at 9 points of composite beam was measured and strain measured mode shape of the beam was calculated from the acquired strains and compared with numerical results by ABAQUS.