Some Aspects of Using the Random Decrement Technique for Nonlinear Systems

Karsten K. Vesterholm*, Rune Brincker, Anders Brandt

*Corresponding author for this work

    Research output: Chapter in Book/Report/Conference proceedingBook chapterResearchpeer-review


    The random decrement (RD) technique can be used to analyze the response signal from a system that has amplitude dependent modal parameters. The implementation of RD for this purpose is usually done by simply applying the technique at multiple amplitudes in the measured response signal. Modal parameters are then estimated based on RD signatures using well known time domain modal parameter estimation methods. This analysis procedure originates from the invention of the RD technique, and is described by several studies in the literature. However, the RD technique is developed for linear systems, and caution must be exercised when applying it to nonlinear systems. In this study, several aspects of applying of the RD technique on signals exhibiting nonlinear behavior are addressed. The principle of superposition does not apply for a nonlinear system. This means the averaging process in RD can yield corrupted results. The benefit of a sufficiently high sampling rate is described.
    Original languageEnglish
    Title of host publicationNonlinear Structures & Systems : Proceedings of the 38th IMAC, A Conference and Exposition on Structural Dynamics 2020
    EditorsG. Kerschen, M. R. Brake, L. Renson
    Place of PublicationCham
    Publication date2021
    ISBN (Print)978-3-030-47625-0
    ISBN (Electronic)978-3-030-47626-7
    Publication statusPublished - 2021
    Event38th IMAC: A Conference and Exposition on Structural Dynamics - Hourson, United States
    Duration: 10 Feb 202013 Feb 2020


    Conference38th IMAC
    Country/TerritoryUnited States
    SeriesConference Proceedings of the Society for Experimental Mechanics Series


    • Random decrement
    • Nonlinear system
    • Random vibrations
    • Signal processing
    • System identification


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