The acoustic black hole (ABH) structure has gradually become a research hotspot in recent years due to its ascendant capacity of vibration attenuation and energy accumulation. To further improve the performance of vibration and noise reduction, the ultra-low frequency broadband gap of a one-dimensional structure embedded ABHs with power-law material properties is investigated in this paper. Based on the Euler-Bernoulli theory, the Transfer Matrix Method (TMM) is used to establish the dynamic model of the dual power-law ABH (DP-ABH) beam. The band structure results obtained by TMM and the finite element method are compared with each other to verify the ultra-low broadband gap of the structure. Comparison with the traditional ABH show that the ultra-low frequency performance of the DP-ABH is due to the enhanced local resonator properties with reduction of dual power-law local stiffness. Parameter analysis served as a guide for optimization is carried out and a method of combining NSGA-II and TMM is applied to optimize the ABH section with full parameters, to consider a trade-off between lower bandgaps and higher stiffness. The investigation shows that the ultra-low broadband gaps of the periodic DP-ABHs structure, which meets adequate stiffness requirements, can be designed by optimized configuration.
In this paper, we present a study of vibration characteristics of the double-beam structures combined with the concept of the acoustic black hole (ABH), which is an effective technique for vibration and noise control. In the proposed double-beam structure, the ABH beam as the vibration damper is attached to the primary uniform beam by a range of translational and rotational springs. We formulate the closed-form spectral element matrix of the double-beam structure and calculate the natural frequencies and mode shapes of the system. The results demonstrate the ABH effect of increasing the modal damping ratios. We also study the power flow and mechanical intensity of the system to offer physical insight into the vibration suppression mechanism of the ABH. A detailed parametric analysis of both translational and rotational springs is carried out. The investigation contributes to the exact dynamic modelling and analysis of the double-beam system containing ABH elements. Furthermore, the proposed ABH double-beam structure shows great potential for vibration control and energy harvesting.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.