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Earthquakes and Structures
  Volume 15, Number 3, September 2018 , pages 263-273
DOI: https://doi.org/10.12989/eas.2018.15.3.263
 


Enhanced least square complex frequency method for operational modal analysis of noisy data
V. Akrami and S. Majid Zamani

 
Abstract
    Operational modal analysis is being widely used in aerospace, mechanical and civil engineering. Common research fields include optimal design and rehabilitation under dynamic loads, structural health monitoring, modification and control of dynamic response and analytical model updating. In many practical cases, influence of noise contamination in the recorded data makes it difficult to identify the modal parameters accurately. In this paper, an improved frequency domain method called Enhanced Least Square Complex Frequency (eLSCF) is developed to extract modal parameters from noisy recorded data. The proposed method makes the use of pre-defined approximate mode shape vectors to refine the cross-power spectral density matrix and extract fundamental frequency for the mode of interest. The efficiency of the proposed method is illustrated using an example five story shear frame loaded by random excitation and different noise signals.
 
Key Words
    Operational Modal Analysis (OMA); ambient vibration; frequency domain; Least Square Complex Frequency (LSCF) method; mode shape; noise signal
 
Address
V. Akrami: Faculty of Engineering, University of Mohaghegh Ardabili, Ardabil, Iran
S. Majid Zamani: Structural Engineering Department, Road, Housing and Urban Research Center, Tehran, Iran
 

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