베어링 간극에 따른 회전기계의 위험 회전속도 회피를 위한 주파수 분석

다국어 초록 (Multilingual Abstract)

This study is concerned with the abnormality monitoring of the rotor unbalance that is one of the most common causes of severe vibration of rotating machinery. This study analyze the relationship between the eccentricity and vibration characteristics for the purpose of abnormal monitoring of rotating machinery with unbalance rotor. Based on the Jeffcott rotor model, the rubbing of a rotating system composed of a rotor and a bearing was formulated to predict the displacement of the rotor in terms of the eccentricity of the rotor, the clearance between the bearing and the rotor, and the rotational speed. The coupled differential equations of Jeffcott rotor is used to analyze the nonlinear dynamic behavior of rotor caused by rub-forces between rotor and bearing. The mathematical model including the eccentricity of the rotor, the clearance between the bearing and the rotor, and the rotational speed is used to derive the motion of rotor in time domain. The motion of the rotor is analyzed both in the frequency domain and the timefrequency domain using Fast Fourier Transform and Hilbert-Huang Transform, respectively, to predict the critical speed.

목차 (Table of Contents)

• ABSTRACT
• 1. 서론
• 2. 주파수 영역 분석 방법
• 3. 회전계의 수학적 모델
• 4. 수학적 모델의 수치해석
• 5. 주파수 분석
• 6. 결론
• References

참고문헌 (Reference)

1 Al-Bedoor, B. O., "Transient Torsional and Lateral Vibrations of Unbalanced Rotors with Rotor-stator Rubbing" 3 (3): 627-645, 2000

2 Huang, N. E., "The Empirical Mode Decomposition and the Hilbert Spectrum for Nonlinear and Non-stationary Time Series Analysis" 454 : 903-995, 1998

3 Rao, S. S., "Mechanical Vibrations" PEARSON 480-651, 2011

4 Peng, Z., "Feature Extraction of the Rub-impact Rotor System by Mean of Wavelet Analysis" 259 (259): 1000-1010, 2003

5 Choi, Y. S., "Experimental Investigation of Partial Rotor Rub" 14 (14): 2150-1256, 2000

6 Choi, Y. S., "Effect of Friction and Eccentricity on Rubbing Phenomenon" 6 (6): 819-825, 1996

7 "Dyrobes"

8 Peng, Z. K., "Detection of the Rubbing-caused Impacts for Rotor-stator Fault Diagnosis Using Reassigned Scalogram" 19 : 391-409, 2005

9 Chu, F., "Bifurcation and Chaos in a Rub-impact Jeffcott Rotor System" 210 (210): 1-18, 1998

10 Chávez, J.P., "Bifurcation Analysis of Periodic Orbits of a Nonsmooth Jeffcott Rotor Model" 18 (18): 2571-2580, 2013