Research Output

Impulse excitation measurement of small changes in elastic moduli and damping using R

  Impulse excitation is commonly used to assess wood stiffness in both scientific and industrial settings. Modes of vibration are excited by a mechanical impulse and their resonant frequencies measured to calculate elastic moduli. It is also possible to assess damping, which is an important property for wood used in musical instruments. This paper covers finer details of the signal analysis necessary when making very accurate measurements. Provided code for Open Source statistical software R is illustrated with data from an experiment tracking small changes in Douglas-fir clear wood during thermal treatment. A frequency domain interpolation method is introduced that enhances the potential precision of the technique to a very high degree, with computational efficiency, even when using inexpensive audio equipment. With multiple measurements, resonant frequencies can be assessed to a precision of 0.1 Hz and better, allowing for tracking of very small changes due to wood treatments or moisture content.

  • Type:


  • Date:

    21 May 2018

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  • DOI:


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  • ISSN:


  • Library of Congress:

    TA Engineering (General). Civil engineering (General)

  • Dewey Decimal Classification:

    674 Lumber processing, wood products & cork

  • Funders:

    Edinburgh Napier Funded


Ridley-Ellis, D., Libeau, M., & Mignerat, D. (2018). Impulse excitation measurement of small changes in elastic moduli and damping using R. International Wood Products Journal, 1-6.



Non-destructive testing; acoustics; resonance; vibration; heat treatment; open source; wood quality

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