Truncated acoustic black hole structure with the optimized tapering shape and damping coating

The acoustic black hole (ABH) structure can be an option as a vibration damper by providing a tapered wedge at the end of a beam or plate. However, not much work has been done on design to yield an effective ABH design for such a plate. We attempt to optimize the shape of the ABH to effectively attenuate the bending vibration in the frequency bands of interest. A preliminary study is also conducted to find the relation between the vibration reduction in a whole plate and the wedge parameters, like various dimensions of the wedge and the damping material property covering the wedge, to understand the general behavior of an ABH structure. With constraints on the range of flare constant, truncated length of the ABH thin end, and thickness of damping material, the wedge profile and parameters are optimized. All computations are based on the three-dimensional finite element modeling of finite plates having ABH structure, and a surrogate model is employed to facilitate the optimization. The results show that the optimized ABH shape without damping is not much better than the non-optimized one, but that with damping exhibits a significant improvement compared to the non-optimized ones, with and without damping.