• 한국해양공학회지
• /
• 제34권3호
• /
• pp.194-201
• /
• 2020

In this study, an optical-fiber sensor was used to measure loads that could act in an environment similar to the loading conditions that exist in an actual pipe. The structure and the installation method of the optical-fiber strain sensor were applied considering the actual large pipe and the buried pipe environment. Load tests were performed using a displacement sensor and sandbags to determine the deflection of the pipe according to the external load, and the linear measurement results were verified. Considering the conditions that could exist in the actual pipe, the test method was presented, and the strain of the buried pipe generated at this time was measured.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2013년도 춘계학술대회 논문집
• /
• pp.1051-1052
• /
• 2013

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권1호
• /
• pp.191-198
• /
• 2001

In order to comprise a basic closed-loop control system for hydraulic systems it is necessary to detect the piston rod stroke of a hydraulic cylinder. There are many conventional type sensors which can detect the displacement of cylinders. However, they cannot reveal the original performance normally or they cannot be applied at all where the operating circumstance of cylinders is beyond specifications of sensors. Especially, for the purpose of detecting the strokes of cylinders mounted on heavy equipments, a special exclusive sensor must be used because the operating circumstances of heavy equipments are so severe that general purpose sensors cannot endure such circumstance as shock and a residual vibration induced by rough works. In this paper, an exclusive method for detecting the piston rod stroke for heavy equipments is suggested, which adopts a remote detecting technique using optical fiber sensors. Several experiments using the prototype are executed for verifying the effectiveness of the suggested method and the possibility of the accurate detection of stroke.

• 동력기계공학회지
• /
• 제16권6호
• /
• pp.86-91
• /
• 2012

A multi purpose environmental monitoring system has been developed as a commercially available standard using the techniques which are FBG(Fiber Bragg Grating), Hetero-core spliced fiber optic sensor and etc, for the purposes of monitoring large scaled structures and preserving natural environments. The monitoring system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed systems in the previous works conveniently provided us with various options of sensor modules intended for monitoring such physical quantities as displacement, distortion, pressure, binary states, and liquid adhesion. In this paper, we extend the previous results to a water leakage detection problem and develop a sensing system as a result. By the experimental study, it is verified that multi-point leakage detection is possible using single line optical fiber.

• 한국광학회지
• /
• 제17권2호
• /
• pp.136-142
• /
• 2006

광강도 변조방식 광섬유 센서의 변위응답해석에 필요한 투광 조도분포를 수학적으로 모델링 하였다. 유도된 조도분포 모델은 스텝인덱스 멀티모드 광섬유를 대상으로 하며 실험적 검증을 통해 타당성을 확인하였다. 검증된 조도분포 모델을 적용하여 얻은 광섬유 센서의 변위응답 해석결과를 변위측정 결과와 비교하여 거의 일치함을 확인하였다. 또한 기존의 가우시안 조도분포 모델을 적용한 해석결과와 비교했을 때 제안한 조도분포 모델이 보다 정확한 결과를 나타냄을 보이고 있다.

• 한국재난관리표준학회지
• /
• 제1권3호
• /
• pp.77-81
• /
• 2008

본 논문에서는 기존 광파이버센서가 갖는 문제점을 보완할 수 있는 새로운 형태의 광파이버 센서에 대해 소개한다. 저자 등이 개발한 헤테로코어형 광파이버센서는 비교적 간단하면서도 큰 곡률 반경에 있어서 전달손실이 발생하며 민감한 손실특성을 나타내는 원리를 이용한 것이다. 또한 원리상 온도의존성이 거의 없어 온도보상이 필요 없고, 마크로벤딩에 의한 광량변화를 검출하는 방식이므로 파단우려가 없는 것도 가장 큰 장점 중의 하나이다. 이러한 특징을 갖는 센서에 대한 내환경특성을 분석하고 평가하기 위해, 본 논문에서는 헤테로코어 형 광파이버센서를 이용하여 각종 환경정보를 모니터링하는 광네트워크형 멀티환경 모니터링 시스템을 구성 할 경우 고려해야 할 특성에 대해 검토하였다. 즉, 온도변화에 대한 센싱 시스템의 강인성을 실험을 통해 확인하였다. 이것은 실용적 관점에서 계측시스템 전체의 환경변화에 대한 종합적인 평가를 수행하는 것을 의미하며 그 결과를 본 논문에 소개한다.

• Nuclear Engineering and Technology
• /
• 제42권3호
• /
• pp.319-328
• /
• 2010

Bonded tendons have been used in reactor buildings at some operating nuclear power plants in Korea. Assessing prestress force on these bonded tendons has become an important pending problem in efforts to assure continued operation beyond their design life. The System Identification (SI) technique was thus developed to improve upon the existing indirect assessment technique for bonded tendons. As a first step, this study analyzed the sensitivity of the key parameters to prestress force, and then determined the optimal parameters for the SI technique. A total of six scaled post-tensioned concrete beams with bonded tendons were manufactured. In order to investigate the correlation of the natural frequency and the displacement to prestress force, an impact test, a Single Input Multiple Output (SIMO) sine sweep test, and a bending test using an optical fiber sensor and compact displacement transducer were carried out. These tests found that both the natural frequency and the displacement show a good correlation with prestress force and that both parameters are available for the SI technique to predict prestress force. However, displacements by the optical fiber sensor and compact displacement transducer were shown to be more sensitive than the natural frequency to prestress force. Such displacements are more useful than the natural frequency as an input parameter for the SI technique.

• 유공압시스템학회논문집
• /
• 제7권2호
• /
• pp.1-6
• /
• 2010

A new type fiber optic sensing system has been developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensor, for the purposes of monitoring large scaled structures, preserving natural environments and measuring physical phenomenons. The sensing system has been tested and evaluated in a possible outdoor condition in view of the full scaled operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended to measure such physical quantities as displacement, distortion, pressure, binary states and liquid adhesion. The experiment study has been performed to examine the performance to a pseudo-cracking experiment in the outdoor situation, and to clarify temperature influences to the system in terms of the coupling of optical connectors and the OTDR stability. It has been verified that the sensing system is robust to the temperature change ranging from the general condition to the hard condition. Especially, in this study, the specification and performances of the pressure sensor have been demonstrated to show the capability of inspecting various physical quantities.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2003년도 춘계학술대회 논문집
• /
• pp.472-477
• /
• 2003

Spindle state monitoring is getting more and more important according to the technology trend of spindle that is accurate and automated. Spindle state monitoring is to measure the state of rotation vibrations. The spindle rotation error motion detected by sensing device includes rotation object's unbalance, external forced vibrations, shape error of spindle, as well as measuring error of monitoring device. In this paper, we have inspected the runout characteristics. Also, we introduce the way to exclude the runout element that appear while you monitor a spindle state.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제55권5호
• /
• pp.263-266
• /
• 2006

An optical microphone was developed using a dual-core multi-mode fiber block and a membrane type micromirror. The fiber block serves as a compact optical head, and the micromirror as a reflective diaphragm. The micromirror is designed to be suspended through a silicon bar connected t a frame, allowing for displacement induced by acoustic waves. The optical head is implemented by integrating two multi-mode fibers in a single block, and used to transfer light signals between it and the diaphragm. For the assembled microphone, its static characteristics were observed to reveal the operating point defined as the optimum distance between the optical head and the diaphragm. And its dynamic response was tested to exhibit a frequency bandwidth of 3 kHz with the variation of $\sim5dB$.