A previously proposed planar axisymmetric dynamic vibration absorber (DVA), with embedded acoustic black hole (ABH) features, has been shown to suffer from the very selective coupling with the host structure, thus compromising its vibration reduction performance. To tackle the problem, an eccentric ABH-based circular DVA whose thickness profile is tailored according to a circumferential gradient variation is proposed in this paper. This new configuration preserves the ABH profile in the radial direction alongside a continuous variation along the circumferential direction and breaks the axisymmetry of the original DVA design at the same time. While the former permits the ABH features to fully play out in a continuous manner, the later entails a more effective coupling with the host structure. These salient properties have been demonstrated and confirmed both numerically and experimentally by examining a benchmark plate structure. For analyses, a coupling model embracing the host structure and the add-on DVAs is established which allows the calculation of the coupling coefficient, a vital quantity to guide the DVA design. Studies demonstrate the advantages of the proposed DVA over existing designs for the same given mass. The enriched structural coupling and the enhanced modal damping, arising from the eccentric and circumferentially graded ABH design, are shown to be the origin of such improvement. All in all, the physical process underpinning the dynamic absorber principle and waveguide absorber from the host structures is simultaneously consolidated, thus leading to superior broadband structural vibration suppression.

Previous efforts in developing acoustic black hole (ABH) based add-on dynamic vibration absorbers (DVA) show promise as well as unresolved challenges, especially in terms of ensuring effective coupling with host structures under control. In this study, a partitioned ABH-featured dynamic vibration absorber (PABH-DVA), consisting of a symmetric ABH-DVA with partitions in the radial direction of the disc, is proposed. By using a plate as host structure, both simulation and experiment were carried out and the results show the new PABH-DVA yields better damping performing than the original symmetric ABH-DVA. To further reveal the mechanism which enables damping enhancement, the coupling coefficients of the two ABH-DVAs were calculated and compared. The simulation results show that the PABH-DVA has more coupled modes, with sometimes lower coupling coefficients than the symmetric ABH-DVA. The influence of the frequency ratio and modal mass were further analyzed and used to explain the reasons why the PABH-DVA delivers higher damping performance. The influence of the number of slits and their orientation were also discussed.