Damping control for improvement of acoustic black hole effect

Acoustic Black Holes are innovative solutions to damp vibrations through the use of power-law profiles in flexural beams and plates. However practical implementations of the concept are limited due to the finiteness of the thickness at the end of the beam. In this paper, it is proposed to add a viscoelastic layer on the ABH and control its mechanical properties by varying the temperature of the material in order to obtain an ABH with tunable properties. A design methodology of the damping layer is proposed, based on the computation of the reflection coefficient of the ABH termination, hence independent from the excitation and the boundary conditions of the host structure. This optimization is performed at a temperature close to the glass transition of the viscoelastic material in order to find the configuration providing the highest dissipation. Then, by controlling the temperature of the patch it is easy to tune the behavior of the ABH according to the practical application which is considered. (C) 2019 Elsevier Ltd. All rights reserved.