Non-stationary signal decomposition approach for harmonic responses detection in operational modal analysis. (1st January 2021)

• Record Type: Journal Article
• Authors: Kang, Jie; Liu, Li; Shao, Yu-Pei; Ma, Qing-Gang
• Is Part Of: Computers & structures. Volume 242(2020)
• Publication Date: 2021-01-01
• Subjects: Operational modal analysis -- Non-stationary signal decomposition -- Harmonic excitation -- Close modes -- Linear time-varying structure; AFD Absolute Frequency Deviation -- CWT Continuous Wavelet Transform -- EMD Empirical Mode Decomposition -- FS-TARMA Functional Series TARMA -- FS-TARMA-PSD FS-TARMA based power spectral density -- HHT Hilbert Huang Transform -- LTV Linear Time-Varying -- MAC Modal Assurance Criterion -- OMA Operational Modal Analysis -- PDF Probability Density Function -- SVD Singular Value Decomposition -- TARMA Time-dependent AutoRegressive Moving Average -- TFA Time-Frequency Analysis -- TFDD Time-Frequency Domain Decomposition -- TFR Time-Frequency Representation -- TV Time-Varying -- WFT Windowed Fourier Transform; Structural engineering -- Data processing -- Periodicals; Electronic data processing -- Structures, Theory of -- Periodicals; 624.171
• DOI: 10.1016/j.compstruc.2020.106377
• Languages: English
• ISSNs: 0045-7949

Abstract

Highlights: A time–frequency representations based signal decomposition method is proposed. A statistics-driven indicator is used to recognize the harmonic components. A time–frequency domain decomposition method is proposed to identify close modes. Abstract: This paper proposes a non-stationary signal decomposition approach to remove the harmonic responses in the operational modal analysis for time-varying structures. Two time–frequency representations, the non-parametric windowed Fourier transform and the power spectral density estimated by the parametric functional series time-dependent autoregressive moving average model, are combined to decompose the raw multimodal responses into individual unimodal components. According to the histogram shape or the excess Kurtosis value of the components, the harmonic components and structural components can be distinguished and the harmonic ones will be removed in the modal identification. To identify the close modes of a time-varying structure, a time–frequency domain decomposition method based on the power spectral density matrix and singular value decomposition technique is also proposed. The numerical and experimental examples finally demonstrate that the proposed approach can remove the harmonic components effectively and can obtain good modal parameters identification results for time-varying structures with close or even repeated modes.