Modal Overlap Factor of a beam with an acoustic black hole termination

Vivien Denis (1) , Adrien Pelat (1) , François Gautier (1) , Benjamin Elie (2)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 MULTISPEECH - Speech Modeling for Facilitating Oral-Based Communication

Acoustic Black Hole (ABH) effect is a passive vibration reduction technique which takes advantage of properties of wave propagation in thin structures of varying thickness. A practical implementation of ABH on a uniform beam consists in an extremity whose thickness follows a power-law profile covered by a very thin layer of additional damping material. A modal analysis based on a High Resolution technique shows that the ABH significantly increases the Modal Overlap Factor (MOF) of the beam, thus reducing the resonant behaviour of the structure. Further investigations, including a two dimensional numerical model of the structure based on the finite difference method, show that this MOF can be explained by an increase of the modal density and a high damping of a number of modes of the structure due to the ABH.

Mots clés: flexural vibration; damping; modal analysis; acoustic black hole; passive damping technique

Domaines: Vibrations [physics.class-ph]

Vivien Denis, Adrien Pelat, François Gautier, Benjamin Elie. Modal Overlap Factor of a beam with an acoustic black hole termination. Journal of Sound and Vibration, 2014, 333 (12), pp.2475-2488. ⟨10.1016/j.jsv.2014.02.005⟩. ⟨hal-01288274⟩