• 센서학회지
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• 제15권1호
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• pp.40-46
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• 2006

This paper presents a novel fiber optic accelerometer system for monitoring vibration of large-size structures. The system is composed of one (or multiple) sensor head, a light control unit and a signal processing unit. The sensing mechanism of the sensor head is based on a novel integration of the moire fringe phenomenon with fiber optics to achieve a robust performance in addition to its immunity to EM interference, easy cabling, and low cost. In this paper, a prototype of the fiber optic accelerometer system has been developed successfully. A low-cost light control unit has been developed to drive the system's optic and electronic components. A unique algorithm has also been developed to derive the sensor's acceleration from the raw signals of the light control unit; it is implemented via a separate signal processing unit. Finally, the shaking table tests successfully demonstrate the performance and the potential of the moire fringe fiber optic sensor system to monitor the health of civil infrastructures.

• 비파괴검사학회지
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• 제27권4호
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• pp.291-298
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• 2007

본 논문은 단자유도 동적 센서 시스템의 동적 구간을 조절할 수 있는 새로운 신호 처리법을 소개한다. 또한 본 논문에서는 무아래 현상을 응용한 신개념의 광섬유 가속도계를 사용하여 신호 처리법을 검증하였다. 신개념의 광섬유 가속도계는 단일 질량, 단일 탄성자 그리고 단일 감쇠자로 이루어진 단자유도 동적 시스템으로서 동적 구간이 작아 이출 증가시키기 위해서는 질량이나 탄성자 상수를 조절하는 등의 기계적 조절이 필요하다. 그러나 본 논문에서 제안한 신호처리 방법을 적용한다면 센서를 다시 제작하지 않고도 동적 구간을 쉽게 조절할 수 있게 된다. 본 논문에서는 여러 모의실험과 실제 실험을 통해 본 신호 처리 알고리즘의 성능을 검증하였으며 결과적으로 이러한 신호처리 알고리즘이 광섬유 가속도계의 동적 구간을 손쉽게 조절할 수 있는 효과적인 방법임을 보여주었다.

• 비파괴검사학회지
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• 제26권6호
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• pp.373-379
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• 2006

Vibration-based structural health monitoring is one of non-destructive evaluation (NDE) techniques for civil infrastructures. This paper presents a novel fiber optic accelerometer system to monitor civil engineering structures and a successful application of the novel sensor system for measuring ambient vibration of a real building structure. This sensor system integrates the Moire fringe phenomenon with fiber optics to achieve accurate and reliable measurements. The sensor system is immune to electromagnetic (EM) interference making it suitable for difficult applications in such environments involving strong EM fields, electrical spark-induced explosion risks, and cabling problems, prohibiting the use of conventional electromagnetic accelerometers. A prototype sensor system has been developed, together with a signal processing software. The experimental studies demonstrated the high-performance of the fiber optic sensor system. Especially, the sensor was successfully used for monitoring a real building on UCI (University of California Irvine, USA).