Identification of modal parameters from nonstationary ambient vibration data using correlation technique

Dar Yun Chiang, Chang Sheng Lin

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Identification of modal parameters is considered from response data of structural systems under nonstationary ambient vibration. It is shown theoretically 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. The practical problem of insufficient data samples available for evaluating nonstationary correlation 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. The theory proposed can be further extended by using the filtering concept to cover the case of nonstationary color excitations. Numerical simulations confirm the validity of the proposed method for identification of modal parameters from nonstationary ambient response data.

Original languageEnglish
Pages (from-to)2752-2759
Number of pages8
JournalAIAA journal
Issue number11
Publication statusPublished - 2008 Nov

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering


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