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광섬유 격자 센서와 회전 광학 커플러를 사용한 회전하는 블레이드 여러 지점에서의 온라인 변형률 측정
이종민(Jong Min Lee),황요하(Yoha Hwang) 대한기계학회 2008 大韓機械學會論文集A Vol.32 No.1
Strain-gauges have been dominantly used to measure strain at various points on a rotor, however, either a slip ring or telemetry has to be used to send sensor signals to data acquisition instruments at stationary side. Both slip ring and telemetry have numerous inherent problems which force severe limitations in real applications. This paper introduces a new rotor condition monitoring system using FBG(Fiber Bragg Grating) sensors and a rotary optical coupler. A single optical fiber with many FBG sensors is installed on the rotor and an optical dynamic interrogator is installed at stationary side. The sensor signal connection between rotating part and stationary part is made by the rotary optical coupling method which makes use of light’s unique characteristic ? light travels through space. Broad band light source from the interrogator travels to the optical fiber on the rotor and reflected FBG sensor signals travel back to the optical fiber on stationary side and are connected to the interrogator. Rotary optical coupler’s insertion loss change due to rotation is compensated by using a reference sensor installed at the center of the rotor. The proposed system’s performance has been successfully demonstrated by accurately measuring strains at 5 points on a blade rotating at high speed.
이인재(Lee, Injae),이종민(Lee, Jong-Min),황요하(Hwang, Yoha),허건수(Huh, Kunsoo) 한국소음진동공학회 2005 한국소음진동공학회 논문집 Vol.15 No.2
Empirical mode decomposition(EMD) method has been recently proposed to analyze non-linear and non-stationary data. This method allows the decomposition of one-dimensional signals into intrinsic mode functions(IMFs) and is used to calculate a meaningful multi-component instantaneous frequency. In this paper, it is assumed that each mode of damped vibration signal could be well separated in the form of IMF by EMD. In this case, we can have a new powerful method to calculate natural frequencies and dampings from damped vibration signal which usually has multiple modes. This proposed method has been verified by both simulation and experiment. The results by EMD method whichhas used only output vibration data are almost identical to the results by FRF method which has used both input and output data, thereby proving usefulness and accuracy of the proposed method.
김종인(Jong In Kim),유홍희(Hong Hee Yoo),황요하(Yoha Hwang) 한국철도학회 1998 한국철도학회 학술발표대회논문집 Vol.- No.-
A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix. The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the three are identified in this paper.
김종인(Jong-In Kim),유홍희(Hong-Hee Yoo),황요하(Yoha Hwang) 한국철도학회 1999 철도저널 Vol.2 No.4
A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix. The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power car vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the two are identified in this paper.