1. Operational modal identification based on parallel factor decomposition with the presence of harmonic excitation
- Author
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Ta, Duc-Tuan, Le, Thien-Phu, and Burman, Michael
- Subjects
Modal analysis ,PARAFAC decomposition ,Covariance function ,Harmonic ,Kurtosis ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
One of the main difficulties of the operational modal analysis is to deal with underdetermined problems in which the number of sensors is less than the number of active modes. In the last decade, methods based on the PARAllel FACtor (PARAFAC) decomposition have attracted a lot of attention in the field of modal analysis because it has been proven that these methods can deal with underdetermined cases, as well as the presence of harmonic excitations. Moreover, in combination with kurtosis value as a harmonic indicator, this makes them more efficient in distinguishing between harmonic and structural components. However, it can lead to distorted results as it does not take into account the variation in the length of the covariance functions of the modal coordinates. Since the kurtosis values are estimated from these covariance functions, the length of the latter directly affects the kurtosis. To overcome this limit, the present study proposes to introduce the choice of the length of these functions based on their frequency and damping coefficient. This change improves the existing method by more efficient separating between harmonics and modal components. The proposed procedure is validated using numerical simulations, followed by ambient vibration measurements.
- Published
- 2021
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