• Title, Summary, Keyword: 광강도형 광섬유 센서

Search Result 7, Processing Time 0.044 seconds

Effect on the structural integrity and fatigue damage monitoring of smart composite structures with embedded intensity based optical fiber sensors (삽입된 광강도형 광섬유센서가 지능형 복합재 구조물의 건전성에 미치는 영향 및 피로손상 감시)

  • Lee, Dong-Chun;Lee, Jung-Ju;Seo, Dae-Cheol;Huh, Jeung-Soo
    • Journal of Sensor Science and Technology
    • /
    • v.10 no.1
    • /
    • pp.42-51
    • /
    • 2001
  • In this study, the effects of embedded optical fibers on the static properties under tensile load and dynamic properties under fatigue load of composite laminates were investigated by experimental tests and finite element analysis. Based on the results, it can be concluded that the embedded optical fiber sensors do not have significant effects on the structural integrity of the smart composite structures except when the sensors are embedded perpendicular to the adjacent reinforcing fibers under fatigue loading. An intensity-based optical fiber sensor was embedded in the crossply composite laminates to monitor the fatigue damage by detecting the stiffness changes of the laminates. The result of this experiment has shown that the intensity-based optical fiber sensor has large potential to monitor the fatigue damage of composite structures by detecting the stiffness changes of the structures with simple and inexpensive instruments and without complex post-processing of measured signals. In addition, the optical fiber sensor showed good resistance to fatigue loading and wide sensing ranges of stiffness.

  • PDF

Fatigue Damage Detection and Vibration Sensing Using Intensity-Based Optical Fiber Sensors (광강도형 광섬유센서를 이용한 피로손상 및 진동감지)

  • 양유창;전호찬;한경섭
    • Composites Research
    • /
    • v.13 no.1
    • /
    • pp.89-97
    • /
    • 2000
  • Fatigue damage detection and vibration sensing for a laminated composites and impact location detection for a steel beam have been carried out using optical fiber sensor. Intensity based optical fiber sensor is constructed by placing two cleaved fiber end in a hollow glass tube, and multiple reflection within the cavity is considered. Fatigue signals are measured by embedded optical fiber, surface mounted optical fiber sensor and strain gage simultaneously. For vibration sensing, optical fiber sensor is mounted on the carbon fiber composite beam and its response to free vibration and forced vibration is investigated. In impact location detection, two optical fiber sensors are used and the information obtained from two sensors is arrival time delay of vibration caused by impact. Impact location can be calculated from this time delay. The obtained results show that the intensity based optical fiber sensor provide reliable data during long-term fatigue loading, unlike strain gage which deteriorate during the early part of the fatigue test. Optical fiber sensor signals coincide with gap sensor in vibration sensing. The precise locations of impact can be detected within 4.1% error limit.

  • PDF

Monitoring of Fatigue Damage of Composite Laminates Using Embedded Intensity-Based Optical Fiber Sensors (광강도형 광섬유 센서를 이용한 복합재 적충판의 피로손상 감시)

  • 이동춘;이정주;서대철
    • Proceedings of the Korean Society For Composite Materials Conference
    • /
    • /
    • pp.124-127
    • /
    • 2000
  • In this study, a technique for monitoring of fatigue damage of composite laminates by measuring the stiffness change using embedded intensity-based optical fiber sensors was investigated. Firstly, the underlying measurement principle and structure of intensity-based sensors and then a simple stiffness conversion process was explained. The monitoring technique was evaluated by fatigue tests of composite laminates with an embedded intensity-based sensor. From the test results, the response of the intensity-based sensor showed good correlation with that of surface mounted extensometer. Therefore, it can be concluded that the intensity-based sensors have good potential for the monitoring of fatigue damage of composite structures under fatigue loading. In addition, it could be confirmed that the intensity-based sensors have higher resistance to fatigue than the commercial electrical strain gauge.

  • PDF

Vibration Sensing and Impact Location Measurement Using Intensity-Based Optical Fiber Vibration Sensor (광강도형 광섬유 진동센서를 이용한 진동감지 및 충격위치 측정)

  • 양유창;황운봉;박현철;한경섭
    • Composites Research
    • /
    • v.13 no.5
    • /
    • pp.1-9
    • /
    • 2000
  • An intensity-based optical fiber vibration sensor is applied to monitor the structural vibration and detect impact locations on a plate. Optical fiber vibration sensor is constructed by placing two cleaved fiber end, one of which is cantilevered in a hollow glass tube. The movement of the cantilevered section lags behind the rest of the sensor in response to an applied vibration and the amount of light coupled between the two fibers is thereby modulated. For vibration sensing, optical fiber vibration sensor is mounted on the carbon fiber composite beam and its response is investigated to free and forced vibration. In impact location detection, four optical fiber vibration sensors whose location is predetermined are placed at chosen positions and the different arrival times of impact-generated vibration signal are recorded by an FFT analyzer. Impact location can be calculated from these time delays. Experimental results show that optical fiber vibration sensor signals coincide with gap sensor in vibration sensing. The precise location of impact can be detected on an acrylate plate.

  • PDF

Fiber Optic Displacement Sensor System for Structural Health Monitoring (구조 건전성 모니터링을 위한 광섬유 변위 센서 시스템 개발)

  • Lee, Kun-Ho;Ahn, Byung-Jun;Kim, Dae-Hyun
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.31 no.4
    • /
    • pp.374-381
    • /
    • 2011
  • It has been doing to research on novel techniques for structural health monitoring by applying various sensor techniques to measure the deflection in mechanical and civil structures. Several electric-based displacement sensors have many difficulties for using them because of EMI (Electro-Magnetic Interference) noise of many lead-wires when they are installed to many points in the structures. In this paper, it is proposed an affordable intensity-based fiber optic sensor to measure small displacement solving the problems of conventional sensors. In detail, the sensor head was designed on the basis of the principle of bending loss and a basic experiment was performed to obtain the sensitivity, the linearity and the stroke of the sensor. Moreover, a prototype was designed and manufactured to be easily installed to a structure and a real-time control software was also successfully developed to drive the fiber optic sensor system.

Thin dielectric diaphragm pressure sensor with optical readout (광학적 신호감지의 유전박막 다이아프레임을 이용하는 압력센서)

  • Kim, Myung-Gyoo;Ryu, Yang-Woog;Park, Dong-Soo;Kim, Jin-Sup;Lee, Jung-Hee;Sohn, Byung-Ki
    • Journal of Sensor Science and Technology
    • /
    • v.5 no.4
    • /
    • pp.1-7
    • /
    • 1996
  • Optical intensity-type pressure sensor was fabricated by coupling optical fiber with a micromachined thin dielectric diaphragm, which consists of a 300 nm thick $SiO_{2}$ layer sandwiched between 150 nm thick top and bottom $Si_{3}N_{4}$ layers. At the wavelength of the sensor light source near $1.3\;{\mu}m$, the optical transmittance of the diaphragm was about 50 %, but it was decreased to a few percents by depositing $1,000\;{\AA}$ thick gold(Au) layer on the diaphragm, which is sufficient enough to be used as a light reflection layer of the sensor. From the optical output power-pressure characteristics of the sensors, it was found that the output power linearly decreased with increasing applied pressure from 0 to 77 torr regardless of the diaphragm size. The respective sensitivities were 0.52, 0.65, and 0.77 nW/torr for the diaphragm sizes of $3{\times}3$, $4{\times}4$, and $5{\times}5\;mm^{2}$, indicating that the sensitivity increases as diaphragm size decreases.

  • PDF