Dynamic and Static Properties of Double-Layered Compound Acoustic Black Hole Structures

Abstract

The “acoustic black hole” (ABH) phenomenon can be exploited for flexural vibration suppressions in beam and plate structures. Conventional ABH structures, however, are tied with the inherent structural weakness due to the low local stiffness required and possibly high stress concentration caused by the small residual cross-section thickness of the ABH taper, thus hampering their practical applications. In this study, the dynamic and static properties of a compound ABH beam are investigated through numerical simulations. It is shown that, whilst ensuring an effective ABH effect, the compound ABH structure allows a significant improvement in the static properties of the structure. For the former, the compound design is shown to outperform its counterpart in the conventional ABH configuration in terms of the damping enhancement and the vibration suppression. For the latter, the compound ABH structure is also shown to provide much better static properties in terms of structural stiffness and strength. Meanwhile, the structural damping can be further improved by using an extended platform at the tip of tailored profile, which improves the structural strength but reduces the structural stiffness at the same time. Therefore, when choosing the platform length, a balance needs to be struck among the desired ABH effect and the mechanical properties of the structure.

Ultrawide band gaps in beams with double-leaf acoustic black hole indentations

“…30 Such a design has been shown to provide better static and dynamic properties compared with conventional single-layered ABH structures. 31 However, structures with periodic doublelayered ABH indentations and possible induced accumulated ABH effect have not been investigated.…”

Acoustic Black Holes in Structural Design for Vibration and Noise Control

“…Due to the well-known advantages of 3D printing [70], vibration and sound radiation of 3D-printed structures are investigated by researchers. Zhou et al developed a numerical study to investigate the dynamic and static properties of 3D-printed double-layered compound structures with ABHs [24]. Due to small residual thickness of the ABH profile, the structure with ABHs has low local stiffness and high stress concentration.…”

“…In the study of Chong et al [22], a numerical and experimental study on vibration response of the 3D-printed ABH beams was also developed. Furthermore, a series of studies on dynamic and static properties [24] and applications in vibration damping [25] and energy harvesting [8,26] of 3D-printed structures embedded with ABH was also investigated by other researchers.…”

Thermal imaging of the structural damping induced by an acoustic black hole

“…Indeed, all the published studies show that the ABH effect, either in 1D or 2D structures, leads to efficient energy dissipation 14 . Various designs of the ABH devices have been proposed by optimising the thickness profile [15][16][17][18][19] , but the damping profile itself is rarely fully optimised.…”