### Abstract

An effective identification method is developed for the determination of modal parameters of a structure from its measured ambient nonstationary vibration data. It has been shown in a previous paper of the authors that by assuming the ambient excitation to be nonstationary white noise in the form of a product model, the nonstationary response signals can be converted into free-vibration data via the correlation technique. In the present paper, if the ambient excitation can be modeled as a nonstationary white noise in the form of a product model, then the nonstationary cross random decrement signatures of structural response evaluated at any fixed time instant are shown theoretically to be proportional to the nonstationary cross-correlation functions. The practical problem of insufficient data samples available for evaluating nonstationary random decrement signatures can be approximately resolved by first extracting the amplitude-modulating function from the response and then transforming the nonstationary responses into stationary ones. Modal-parameter identification can then be performed using the Ibrahim time-domain technique, which is effective at identifying closely spaced modes. Numerical simulations confirm the validity of the proposed method for identification of modal parameters from nonstationary ambient response data.

Original language | English |
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Title of host publication | Topics in Modal Analysis I - Proceedings of the 30th IMAC, A Conference on Structural Dynamics, 2012 |

Pages | 223-232 |

Number of pages | 10 |

DOIs | |

Publication status | Published - 2012 Jul 24 |

Event | 30th IMAC, A Conference on Structural Dynamics, 2012 - Jacksonville, FL, United States Duration: 2012 Jan 30 → 2012 Feb 2 |

### Publication series

Name | Conference Proceedings of the Society for Experimental Mechanics Series |
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Volume | 5 |

ISSN (Print) | 2191-5644 |

ISSN (Electronic) | 2191-5652 |

### Other

Other | 30th IMAC, A Conference on Structural Dynamics, 2012 |
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Country | United States |

City | Jacksonville, FL |

Period | 12-01-30 → 12-02-02 |

### Fingerprint

### All Science Journal Classification (ASJC) codes

- Engineering(all)
- Computational Mechanics
- Mechanical Engineering

### Cite this

*Topics in Modal Analysis I - Proceedings of the 30th IMAC, A Conference on Structural Dynamics, 2012*(pp. 223-232). (Conference Proceedings of the Society for Experimental Mechanics Series; Vol. 5). https://doi.org/10.1007/978-1-4614-2425-3_20

}

*Topics in Modal Analysis I - Proceedings of the 30th IMAC, A Conference on Structural Dynamics, 2012.*Conference Proceedings of the Society for Experimental Mechanics Series, vol. 5, pp. 223-232, 30th IMAC, A Conference on Structural Dynamics, 2012, Jacksonville, FL, United States, 12-01-30. https://doi.org/10.1007/978-1-4614-2425-3_20

**Modal identification from nonstationary ambient vibration data using random decrement algorithm.** / Lin, Chang Sheng; Chiang, Dar-Yun.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

TY - GEN

T1 - Modal identification from nonstationary ambient vibration data using random decrement algorithm

AU - Lin, Chang Sheng

AU - Chiang, Dar-Yun

PY - 2012/7/24

Y1 - 2012/7/24

N2 - An effective identification method is developed for the determination of modal parameters of a structure from its measured ambient nonstationary vibration data. It has been shown in a previous paper of the authors that by assuming the ambient excitation to be nonstationary white noise in the form of a product model, the nonstationary response signals can be converted into free-vibration data via the correlation technique. In the present paper, if the ambient excitation can be modeled as a nonstationary white noise in the form of a product model, then the nonstationary cross random decrement signatures of structural response evaluated at any fixed time instant are shown theoretically to be proportional to the nonstationary cross-correlation functions. The practical problem of insufficient data samples available for evaluating nonstationary random decrement signatures can be approximately resolved by first extracting the amplitude-modulating function from the response and then transforming the nonstationary responses into stationary ones. Modal-parameter identification can then be performed using the Ibrahim time-domain technique, which is effective at identifying closely spaced modes. Numerical simulations confirm the validity of the proposed method for identification of modal parameters from nonstationary ambient response data.

AB - An effective identification method is developed for the determination of modal parameters of a structure from its measured ambient nonstationary vibration data. It has been shown in a previous paper of the authors that by assuming the ambient excitation to be nonstationary white noise in the form of a product model, the nonstationary response signals can be converted into free-vibration data via the correlation technique. In the present paper, if the ambient excitation can be modeled as a nonstationary white noise in the form of a product model, then the nonstationary cross random decrement signatures of structural response evaluated at any fixed time instant are shown theoretically to be proportional to the nonstationary cross-correlation functions. The practical problem of insufficient data samples available for evaluating nonstationary random decrement signatures can be approximately resolved by first extracting the amplitude-modulating function from the response and then transforming the nonstationary responses into stationary ones. Modal-parameter identification can then be performed using the Ibrahim time-domain technique, which is effective at identifying closely spaced modes. Numerical simulations confirm the validity of the proposed method for identification of modal parameters from nonstationary ambient response data.

UR - http://www.scopus.com/inward/record.url?scp=84864000930&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84864000930&partnerID=8YFLogxK

U2 - 10.1007/978-1-4614-2425-3_20

DO - 10.1007/978-1-4614-2425-3_20

M3 - Conference contribution

AN - SCOPUS:84864000930

SN - 9781461424246

T3 - Conference Proceedings of the Society for Experimental Mechanics Series

SP - 223

EP - 232

BT - Topics in Modal Analysis I - Proceedings of the 30th IMAC, A Conference on Structural Dynamics, 2012

ER -