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Smart Structures and Systems
  Volume 7, Number 1, January 2011, pages 59-82
DOI: http://dx.doi.org/10.12989/sss.2011.7.1.059
 


Output-only modal identification approach for time-unsynchronized signals from decentralized wireless sensor network for linear structural systems
Jae-Hyung Park, Jeong-Tae Kim and Jin-Hak Yi

 
Abstract
    In this study, an output-only modal identification approach is proposed for decentralized wireless sensor nodes used for linear structural systems. The following approaches are implemented to achieve the objective. Firstly, an output-only modal identification method is selected for decentralized wireless sensor networks. Secondly, the effect of time-unsynchronization is assessed with respect to the accuracy of modal identification analysis. Time-unsynchronized signals are analytically examined to quantify uncertainties and their corresponding errors in modal identification results. Thirdly, a modified approach using complex mode shapes is proposed to reduce the unsynchronization-induced errors in modal identification. In the new way, complex mode shapes are extracted from unsynchronized signals to deal both with modal amplitudes and with phase angles. Finally, the feasibility of the proposed approach is evaluated from numerical and experimental tests by comparing with the performance of existing approach using real mode shapes.
 
Key Words
    output-only modal identification; wireless sensor network; time-delayed signals; time-unsynchronization effect; complex mode shapes.
 
Address
Jae-Hyung Park: Department of Ocean Engineering, Pukyong National University, Busan, Korea
Jeong-Tae Kim :Department of Ocean Engineering, Pukyong National University, Busan 608-737, Korea
Jin-Hak Yi: Korea Ocean Research & Development Institute, Ansan, Korea
 

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