Investigation on vibration reduction performance of Quasi-3D spiral acoustic black hole for plate

[Objectives] The aim is to investigate the effect of Quasi-3D spiral acoustic black holes (Q-3D SABH) on the vibration suppression characteristics of flat plates, and to provide a new technical way for the vibration damping design of ship plate structures. [Methods] The study proposes the Q-3D SABH configuration with broadband vibration reduction for the first time, establishes a finite element computational model of a plate structure arranged with Q-3D SABH, calculates and analyzes the vibration response characteristics and velocity cloud diagram of the structure, and reveals the influence law and effect of Q-3D SABH on the vibration suppression of the flat plate through the form of energy flow as well as the modal loss factor. [Results] The results show that the vibration damping effect of Q-3D SABH on the flat plate is significantly better than that of the mass block and damping of the same mass. In the low-frequency band, the arrangement of Q-3D SABH reduces the mean-square vibration velocity level of the flat plate by more than 10 dB, and in the high-frequency band, the damping effect is as high as more than 15 dB, and the total vibration level is reduced by 15.05 dB in the whole frequency band; meanwhile, its damping performance is better than that of a one-dimensional spiral acoustic black hole of equal mass as a whole, and it is more obvious at middle and high frequencies..[Conclusions] It is shown that Q-3D SABH has excellent low-frequency broadband damping performance for plate structures with good convergent absorption of wave energy.