Modal-parameter identification from nonstationary ambient vibration data

Dar-Yun Chiang, Chang Sheng Lin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Identification of modal parameters from response data only is studied for structural systems under nonstationary ambient vibration. By assuming the ambient excitation to be nonstationary white noise in the form of a product model, the modal parameters of a system could be identified through the correlation method in conjunction with a technique of curve-fitting. However, the error involved in the approximate free-decay response would generally lead to a distortion in the modal parameters of identification. It is shown that, under appropriate conditions, the ambient response corresponding to nonstationary input of various types can be approximately expressed as a sum of exponential functions, so that we can use the Ibrahim time-domain method in conjunction with a channel-expansion technique to directly identify the major modes of a structural system without any additional treatment of converting the original data into the form of free vibration. To further distinguish the structural modes from non-structural modes, the concept of mode-shape coherence and confidence factor is employed. Numerical simulations, including one example of using practical excitation data, confirm the validity and robustness of the proposed method for identification of modal parameters from general nonstationary ambient response.

Original languageEnglish
Title of host publicationExperimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics
Pages157-169
Number of pages13
Publication statusPublished - 2011 Dec 1
Event2011 SEM Annual Conference on Experimental and Applied Mechanics - Uncasville, CT, United States
Duration: 2011 Jun 132011 Jun 16

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
Volume6
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652

Other

Other2011 SEM Annual Conference on Experimental and Applied Mechanics
CountryUnited States
CityUncasville, CT
Period11-06-1311-06-16

Fingerprint

Laser modes
Identification (control systems)
Correlation methods
Exponential functions
Curve fitting
White noise
Computer simulation

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Computational Mechanics
  • Mechanical Engineering

Cite this

Chiang, D-Y., & Lin, C. S. (2011). Modal-parameter identification from nonstationary ambient vibration data. In Experimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics (pp. 157-169). (Conference Proceedings of the Society for Experimental Mechanics Series; Vol. 6).
Chiang, Dar-Yun ; Lin, Chang Sheng. / Modal-parameter identification from nonstationary ambient vibration data. Experimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics. 2011. pp. 157-169 (Conference Proceedings of the Society for Experimental Mechanics Series).
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Chiang, D-Y & Lin, CS 2011, Modal-parameter identification from nonstationary ambient vibration data. in Experimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics. Conference Proceedings of the Society for Experimental Mechanics Series, vol. 6, pp. 157-169, 2011 SEM Annual Conference on Experimental and Applied Mechanics, Uncasville, CT, United States, 11-06-13.

Modal-parameter identification from nonstationary ambient vibration data. / Chiang, Dar-Yun; Lin, Chang Sheng.

Experimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics. 2011. p. 157-169 (Conference Proceedings of the Society for Experimental Mechanics Series; Vol. 6).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Chiang D-Y, Lin CS. Modal-parameter identification from nonstationary ambient vibration data. In Experimental and Applied Mechanics - Proceedings of the 2011 Annual Conference on Experimental and Applied Mechanics. 2011. p. 157-169. (Conference Proceedings of the Society for Experimental Mechanics Series).