Vibration attenuation of rotating disks via acoustic black holes

Acoustic black holes (ABHs) have been found to exhibit desirable damping characteristics for vibration attenuation of thin-walled structures. However, up until now, no research has been carried out on evaluating ABH effects on vibrations of rotating structures, of which vibration attenuation issues are usually critical. To fill this knowledge gap, this work proposes a unified modeling approach for rotating thin disks with ABH indentations. The equations of motion of the system are formulated using the Rayleigh-Ritz method together with the Kirchhoff plate theory. The modified Fourier series are employed to form the displacement admissible functions. Finite element analysis is conducted to validate the proposed model. Damping performance of the ABH disk is then investigated under both non-rotating and rotating states. Finally, experiments are carried out to study the vibration attenuation effect of the ABH on non-rotating and rotating disks. The natural frequencies of the ABH disk with viscoelactic layers at different rotating speeds obtained from experiments and numerical calculations are compared to further verify the modeling approach. With all the simulation and experimental results, it is found that ABHs are capable of realizing vibration reduction for rotating structures, where the effectiveness is influenced by rotating speeds and excitation types.