Study on energy propagation and noise radiation in plates containing the array of acoustic black holes

To control car interior noise, a great deal of damping material is pasted on the body plate. This increases car weight and produces a contradiction with the lightweight design idea. Increasing the energy dissipation efficiency of damping material may reduce its usage. It is well known that 'acoustic black hole' (ABH) embedded in the plate structure may gather the vibration energy of plate to a specified area and cause the growth of vibration amplitude in this area, and that the damping material pasted in higher amplitude area has greater energy dissipation efficiency. Therefore, the body plate containing two-dimensional ABH is potential to solve this contradiction. In this paper, a plate model containing the array of five ABHs and the reference plate model are established and simulated, and the power flow method is introduced to analyze the energy propagation characteristics arising from ABH effect. Then the average vibration power density in different plate sections is calculated to quantitatively study the energy focalization effect. Next, the plate model containing ABHs with damping layer is designed and its energy dissipation effect is investigated. Finally, the radiated sound power levels of the structures under a given excitation are calculated and discussed.