Modal identification from nonstationary ambient vibration data using random decrement algorithm

Chang Sheng Lin, Dar-Yun Chiang

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

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 languageEnglish
Title of host publicationTopics in Modal Analysis I - Proceedings of the 30th IMAC, A Conference on Structural Dynamics, 2012
Pages223-232
Number of pages10
DOIs
Publication statusPublished - 2012 Jul 24
Event30th IMAC, A Conference on Structural Dynamics, 2012 - Jacksonville, FL, United States
Duration: 2012 Jan 302012 Feb 2

Publication series

NameConference Proceedings of the Society for Experimental Mechanics Series
Volume5
ISSN (Print)2191-5644
ISSN (Electronic)2191-5652

Other

Other30th IMAC, A Conference on Structural Dynamics, 2012
CountryUnited States
CityJacksonville, FL
Period12-01-3012-02-02

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Computational Mechanics
  • Mechanical Engineering

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