Experimental study on damping of flexural waves in rectangular plates by means of one-dimensional acoustic 'Black Holes'
V. Kralovic
E.P. Bowyer
Victor V. Krylov
Daniel O'Boy
2134/10125
https://repository.lboro.ac.uk/articles/conference_contribution/Experimental_study_on_damping_of_flexural_waves_in_rectangular_plates_by_means_of_one-dimensional_acoustic_Black_Holes_/9220973
In this paper we present some recent experimental results on new lightweight
and broad-band damping treatment for rectangular plates based on the so-called
acoustic ‘black hole’ effect [1-5], which represents one of the most efficient ways of
creating graded impedance interfaces [6] to reduce edge reflections of flexural
waves. These acoustic black holes, or vibration 'traps', use elastic wedges of variable
thickness defined by a power-law relationship h(x) = ε·xm (with m ≥ 2) to reduce edge
reflections. In the ideal case of no edge truncations, bending wave velocities
decrease to zero in such a way that the waves never reach the end and hence do not
reflect back. They thus represent one-dimensional acoustic ‘black holes’ for flexural
waves. It was predicted [2,3] that very low values of reflection coefficient can be
achieved even in the presence of truncations and imperfections when a narrow layer
of absorbing material is attached to its surface in order to dissipate the remaining
energy (note that direct application of thin layers of absorbing materials to the
surfaces of rectangular plates has a negligible influence on damping, which has also
been demonstrated during the tests). (Continues...)
2012-07-26 10:46:47
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