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Experimental identification of closely spaced modes using NExT-ERA

Hosseini Kordkheili, S. A ; Sharif University of Technology | 2018

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jsv.2017.09.038
  3. Publisher: Academic Press , 2018
  4. Abstract:
  5. This article presents a study on the capability of the time domain OMA method, NExT-ERA, to identify closely spaced structural dynamic modes. A survey in the literature reveals that few experimental studies have been conducted on the effectiveness of the NExT-ERA methodology in case of closely spaced modes specifically. In this paper we present the formulation for NExT-ERA. This formulation is then implemented in an algorithm and a code, developed in house to identify the modal parameters of different systems using their generated time history data. Some numerical models are firstly investigated to validate the code. Two different case studies involving a plate with closely spaced modes and a pulley ring with greater extent of closeness in repeated modes are presented. Both structures are excited by random impulses under the laboratory condition. The resulting time response acceleration data are then used as input in the developed code to extract modal parameters of the structures. The accuracy of the results is checked against those obtained from experimental tests. © 2017 Elsevier Ltd
  6. Keywords:
  7. Closely spaced modes ; Experimental identification ; Time domain OMA method ; Codes (symbols) ; Modal analysis ; Structural dynamics ; Correlation function ; NExT-ERA method ; Time domain ; Time domain analysis
  8. Source: Journal of Sound and Vibration ; Volume 412 , 2018 , Pages 116-129 ; 0022460X (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0022460X17307010