Enhanced EMD-RDT Method for Output-Only Ambient Modal Identification of Structures
Publication: Journal of Aerospace Engineering
Volume 32, Issue 4
Abstract
An enhanced approach of empirical mode decomposition based random decrement technique (EMD-RDT) is proposed for output-only modal parameter identification of structures using ambient vibration measurements. In the conventional EMD-RDT method, modal parameters are identified for each mode through Hilbert transform or least-square fitting from the free-decay modal responses, which are produced by EMD and RDT sequentially. The identification process is time consuming, and many uncertainties are involved. The novel enhancements of the proposed method lie in two aspects: computation efficiency and uncertainty treatment. On one hand, a novel decomposition method is proposed to separate the mode shape and the modal coordinates from the free-decay modal responses, thus making the identification process more efficient. On the other hand, a bootstrap approach is employed to quantify the uncertainties of modal parameters by providing surrogate estimates to generate useful statistics. Examples using both simulated data from a six degrees-of-freedom (six-DOF) system and experimental data from a three-story shear building structure are presented to demonstrate the proposed method, of which the effectiveness and the efficiency are confirmed by the identified results.
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Acknowledgments
This research was supported by National Natural Science Foundation of China (Grant No. 51708203), the Fundamental Research Funds for the Central Universities (Grant No. 531107050913), the Open Research Fund Program of Guangdong Key Laboratory of Earthquake Engineering and Application Technology (Grant No. 2014B030301075-02), the Open Research Fund Program for innovation platforms of universities in Hunan province from the Education Department of Hunan Province (Grant No. 17K022), and an intergovernment corporation project from the State’s Key Research and Development Program of China (No. 2016YFE0127900). These supports are gratefully acknowledged. Findings and opinions expressed here, however, are those of the authors alone, not necessarily the views of the sponsors.
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Published In
Journal of Aerospace Engineering
Volume 32 • Issue 4 • July 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Aug 2, 2018
Accepted: Jan 22, 2019
Published online: Apr 30, 2019
Published in print: Jul 1, 2019
Discussion open until: Sep 30, 2019
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