Loughborough University
Browse
Krylov AAA 2004 - postprint.pdf (425.7 kB)

New type of vibration dampers utilising the effect of acoustic 'black holes'

Download (425.7 kB)
journal contribution
posted on 2013-03-05, 09:14 authored by Victor V. Krylov
One of the well-known ways of damping resonant flexural vibrations of different engineering structures or their elements, e.g. finite plates or bars, is to reduce reflections of flexural waves from their free edges. In the present paper, a new efficient method of reducing edge reflections is described that utilises gradual change in thickness of a plate or a bar from the value corresponding to the thickness of the basic plate to almost zero. It is proposed to use specific power-law shapes of plates of variable thickness (wedges) that ideally provide zero reflection even for negligibly small material attenuation – the so-called ‘acoustic black hole effect’. In particular, for powers m ≥ 2 - in free wedges, and m ≥ 5/3 – in immersed wedges, incident flexural waves become trapped near the edge and do not reflect back. Since, because of ever-present edge truncations in real manufactured wedges, the corresponding reflection coefficients are always far from zero, to make up for real wedges and make the systems more efficient it is proposed to deposit absorbing thin layers on wedge surfaces. It is shown that the deposition of thin damping layers on the wedge surfaces can dramatically reduce the reflection coefficients. Thus, the combination of a wedge with power-law profile and of thin damping layers can utilise the acoustic ‘black hole’ effect resulting in very effective damping systems for flexural vibrations.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Citation

KRYLOV, V.V., 2004. New type of vibration dampers utilising the effect of acoustic 'black holes'. Acta Acustica united with Acustica, 90 (5), pp. 830-837.

Publisher

© Hirzel Verlag (S. Hirzel Verlag)

Version

  • AM (Accepted Manuscript)

Publication date

2004

Notes

The archived file is not the final published version of the article. The definitive publisher-authenticated version is available online at http://www.ingentaconnect.com/content/dav/aaua. Readers must contact the publisher for reprints or permission to use the material in any form.

ISSN

1610-1928

eISSN

1861-9959

Language

  • en

Usage metrics

    Loughborough Publications

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC