Department News
THE MYSTERY OF MODULATION SIDEBANDS OBSERVED IN MECHANICAL SYSTEMS
Seminar Date
2004-12-09
Author
임아주
Date
2004-12-09
Views
1764
1. 제 목 : THE MYSTERY OF MODULATION SIDEBANDS OBSERVED IN
MECHANICAL SYSTEMS
2. 연 사 : Prof. R. Singh (Dept. of Mechanical Engineering , The Ohio State University)
3. 일 시 : 2004년 12월 13일 월요일 15:30~16:30
4. 장 소 : 차세대자동차연구센터(314동) 2층 세미나실
5. 내 용 :
Sideband structures are commonly observed in measured vibro-acoustic spectra of many mechanical systems such as gears, bearings, fans and motors. Though the modulated spectral contents are often utilized to trouble shoot practical noise and vibration problems and to develop algorithms for fault detection, several aspects of the problem are not well understood. Kinematic, Fourier and/or Communication theories are often used to identify the existence of frequencies but they can not seem to explain the amplitude behavior, including the asymmetric nature of some sidebands. A dual-domain periodic differential equation with an implicit non-linearity will be presented to plausibly explain the underlying physics. Analytical predictions, based on a force modulation concept, will be compared with dynamic measurements on a gear pair, as well as with computational studies. Then, an acoustic duct experiment will be described where two active control algorithms are employed to suppress the amplitude or frequency modulated sounds at carrier frequencies and their sidebands. Sound quality issues will also be briefly discussed in terms of a semi-empirical perception index that correlates well with human response. Areas of further research will be identified.
6. 연사약력
The Ohio State University - Professor - 1979 to present
Univ. of California at Berkeley - Visiting Professor - 1987~88
Carrier Corp., United Technologies - Sr. Acoustics & Dynamics Engineer - 1975~79
7. 문 의 : 기계항공공학부 강연준 교수 (☏880-1691)
MECHANICAL SYSTEMS
2. 연 사 : Prof. R. Singh (Dept. of Mechanical Engineering , The Ohio State University)
3. 일 시 : 2004년 12월 13일 월요일 15:30~16:30
4. 장 소 : 차세대자동차연구센터(314동) 2층 세미나실
5. 내 용 :
Sideband structures are commonly observed in measured vibro-acoustic spectra of many mechanical systems such as gears, bearings, fans and motors. Though the modulated spectral contents are often utilized to trouble shoot practical noise and vibration problems and to develop algorithms for fault detection, several aspects of the problem are not well understood. Kinematic, Fourier and/or Communication theories are often used to identify the existence of frequencies but they can not seem to explain the amplitude behavior, including the asymmetric nature of some sidebands. A dual-domain periodic differential equation with an implicit non-linearity will be presented to plausibly explain the underlying physics. Analytical predictions, based on a force modulation concept, will be compared with dynamic measurements on a gear pair, as well as with computational studies. Then, an acoustic duct experiment will be described where two active control algorithms are employed to suppress the amplitude or frequency modulated sounds at carrier frequencies and their sidebands. Sound quality issues will also be briefly discussed in terms of a semi-empirical perception index that correlates well with human response. Areas of further research will be identified.
6. 연사약력
The Ohio State University - Professor - 1979 to present
Univ. of California at Berkeley - Visiting Professor - 1987~88
Carrier Corp., United Technologies - Sr. Acoustics & Dynamics Engineer - 1975~79
7. 문 의 : 기계항공공학부 강연준 교수 (☏880-1691)
