Orthogonal Projection-Based Harmonic Signal Removal for Operational Modal Analysis

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Abstract

A presence of a high amplitude periodic signals in the output responses from operating structures often pose a challenge for output-only system identification and, in case of health monitoring, damage detection/localization methods. This paper introduces a pre-processing approach that removes the harmonic part from the output signals directly in the time domain. The new method uses orthogonal projections of the harmonic realization of the signal onto the raw time series within the stochastic subspace framework. Proposed algorithm is tested on two experimental examples. First, an aluminum plate excited with both random white and periodic excitations. Second, a full-scale industrial case of a ferry excited by a random environmental load with harmonic interference from a rotating machinery on-board. In both cases the proposed method removes the harmonics from the structural responses while leaving the random part of the output signal.
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A presence of a high amplitude periodic signals in the output responses from operating structures often pose a challenge for output-only system identification and, in case of health monitoring, damage detection/localization methods. This paper introduces a pre-processing approach that removes the harmonic part from the output signals directly in the time domain. The new method uses orthogonal projections of the harmonic realization of the signal onto the raw time series within the stochastic subspace framework. Proposed algorithm is tested on two experimental examples. First, an aluminum plate excited with both random white and periodic excitations. Second, a full-scale industrial case of a ferry excited by a random environmental load with harmonic interference from a rotating machinery on-board. In both cases the proposed method removes the harmonics from the structural responses while leaving the random part of the output signal.
Original languageEnglish
Title of host publicationStructural Health Monitoring, Photogrammetry & DIC : Proceedings of the 36th IMAC, A Conference and Exposition on Structural Dynamics 2018
EditorsChristopher Niezrecki, Javad Baqersad
Volume6
PublisherSpringer
Publication date2019
Pages9-21
Chapter2
ISBN (Print)978-3-319-74475-9
ISBN (Electronic)978-3-319-74476-6
DOI
StateE-pub ahead of print - 2019
Publication categoryResearch
Peer-reviewedYes
EventIMAC XXXVI, A Conference and Exposition on Structural Dynamics 2018 - Orlando, United States
Duration: 12 Feb 201815 Feb 2018
Conference number: 36

Conference

ConferenceIMAC XXXVI, A Conference and Exposition on Structural Dynamics 2018
Nummer36
LandUnited States
ByOrlando
Periode12/02/201815/02/2018
SeriesConference Proceedings of the Society for Experimental Mechanics Series
Volume6
ISSN2191-5644

    Research areas

  • Operational modal analysis, Stochastic subspace identification, Rotating machinery, Harmonic removal, Non-stationary harmonics

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