Damping evolution mechanism of panel embedded with heterogeneous acoustic black hole array

Acoustic black hole (ABH) is regarded as an efficient method for passive vibration reduction. The characteristics of ABH indentation in the panel capturing the bending wave leads to a higher energy density, which makes it possible to achieve efficient vibration energy dissipation by attaching the damping material. Inspired by this ABH effect, dynamic performances of the single ABH and ABH array have been investigated by the finite element method and experiments. It is found that ABH array can effectively increase the modal density and modal loss factor of the structure, leading to a better vibration reduction in the broadband frequency. To reveal the damping loss mechanism of ABH structure, models of ABH indentations attached with damping material are constructed and parametric studies are conducted. Results show that modal loss factor of the whole system is not only related to the properties of damping material, but also decided by the amount of modal kinetic energy covered by the damping layer. On the other hand, the modal density is determined by the geometric parameters of the structure. Furthermore, the acting effect by different units in the array has been researched, and different types of ABH arrays are considered. It is found that the heterogeneous array exhibits a more stable dynamic performance than the traditional homogeneous array. These findings are beneficial to the engineering application of ABH array for vibration and noise attenuation, and exploit the potential of novel structures in the future.

Automated summary

The acoustic black hole (ABH) is an efficient method for passive vibration reduction. By indenting the ABH in the panel, higher energy density is captured, allowing for efficient vibration energy dissipation by attaching damping material. The dynamic performances of single ABH and ABH array have been investigated, and it is found that ABH arrays effectively increase modal density and loss factor, resulting in better vibration reduction in a broad frequency range.