Potentialities of the acoustic black hole effect for damping plate vibrations
Résumé
The lightening of mechanical structures, used in the transport industry is nowadays an important issue because of its consequences in terms of saving energy. The consequent mechanical changes degrade the acoustic performance of components. Some innovating strategies for damping vibrations of structures without increasing their mass should be developed. Some wave traps, using the acoustic black hole effect can be used for this purpose. The acoustic black hole effect is based on a local change of the shape and the thickness of a structure in order to create weak points where the vibration amplitudes are efficiently damped by adding a small local damping layer. The aims of the paper is to investigate the damping capability of acoustic black holes placed on plates of different kinds: elliptical, rectangular plates, polygonal plate, stiffened plates. Mobility measurements on a wide frequency range using are showing that a reduction of 10 to 20 dB can be obtained when the acoustic black hole is active. Measurements of the vibration fields in the acoustic black hole zone using a scanning laser vibrometer are used to check the existence of local non linearities which could explain some parts of the observed damping.
Domaines
Acoustique [physics.class-ph]
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