Application of Frequency Domain Decomposition Identification Technique to Half Spectral Densities

  • Sandro AmadorEmail author
  • Martin Ørum
  • Tobias Friis
  • Rune Brincker
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


Because of its simplicity and robustness, the Frequency Domain Decomposition (FDD) identification technique have become very popular in the operational modal analysis community. The basic idea behind this technique consists of computing the singular value decomposition of the power spectral densities estimated with the periodogram (also known as “Welch’s” periodogram) approach to identify the natural frequencies and mode shape vectors. In this paper, the benefits of the application of the FDD technique to half spectral densities – the power spectral densities estimated from the positive part of the correlation functions – are investigated. In order to illustrate such benefits from a practical perspective, the FDD identification results obtained from the half spectral densities, of both simulated and real structures, are compared to those from the classical periodogram-driven FDD.



The authors acknowledge the funding received from Centre for Oil and Gas – DTU/Danish Hydrocarbon Research and Technology Centre (DHRTC).


  1. 1.
    Peeters, B., De Roeck, G.: Reference-based stochastic subspace identification for output-only modal analysis. Mech. Syst. Signal Process. 13(6), 855–878 (1999)CrossRefGoogle Scholar
  2. 2.
    Peeters, B., Van der Auweraera, H., Guillaume, P., Leuridana, J.: The polymax frequency–domain method: a new standard for modal parameter estimation? Shock Vib. 1(11), 395–409 (2004)CrossRefGoogle Scholar
  3. 3.
    Peeters, B., Van Der Auweraera, H., Vanhollebeck, F., Guillaume, P.: Operational modal analysis for estimating the dynamic properties of a stadium structure during a football game. Shock Vib. 1(14), 283–303 (2007)CrossRefGoogle Scholar
  4. 4.
    Brincker, R., Ventura, C.: Introduction to Operational Modal Analysis, 1st edn. Wiley, New York (2015)CrossRefGoogle Scholar
  5. 5.
    Brincker, R., Zhang, L., Andersen, P.: Modal identification of output-only systems using frequency domain decomposition. Smart Mater. Struct. 10, 441–445 (2001)CrossRefGoogle Scholar
  6. 6.
    Shih, C.Y., Tsuei, Y.G., Allemang, R.J., Brown, D.L.: Complex mode indication function and its application to spatial domain parameter estimation. Mech. Syst. Signal Process. 2(4), 367–377 (1988)CrossRefGoogle Scholar
  7. 7.
    Amador, S.D.R., Brincker, R.: On the different derivatives of the half spectral density. In: Proceedings of the 7th International Operational Modal Analysis Conference (IOMAC) (2017)Google Scholar

Copyright information

© The Society for Experimental Mechanics, Inc. 2019

Authors and Affiliations

  • Sandro Amador
    • 1
    Email author
  • Martin Ørum
    • 2
  • Tobias Friis
    • 1
  • Rune Brincker
    • 1
  1. 1.Technical University of DenmarkKongens LyngbyDenmark
  2. 2.Aarhus UniversityAarhusDenmark

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