Enhanced low-frequency wideband vibration mitigation of an acoustic black hole beam utilizing coupled distributed dynamic absorbers

Acoustic Black Holes (ABHs) have garnered significant attention in recent years due to their unique ability to focus vibration energy. The integration of ABHs' broadband focusing properties with the precision tuning capabilities of Dynamic Vibration Absorbers (DVAs) promises to achieve excellent wideband vibration reduction performance. However, the literature remains sparse on the intricate challenges posed by low-frequency multiple resonances, as well as experimental validations of this innovative ABH + DVA approach. In this academic investigation, a lightweight DVA has been meticulously designed and fabricated, tailored for seamless integration with an ABH beam. Rigorous vibration experiments were conducted on the combined ABH + DVA system, yielding conclusive evidence of its remarkable vibration mitigation capabilities. Additionally, the Finite Element Model (FEM) of the ABH + DVA configuration was thoroughly validated against the experimental findings, emphasizing its predictive accuracy. Furthermore, this study delves into the nuanced effects of varying DVA coupling forms and areas on the system's vibration characteristics, offering valuable insights for optimizing the performance of the ABH + DVA architecture. Lastly, a novel beam design incorporating four strategically distributed ABHs coupled with four DVAs is introduced and comprehensively analyzed through FEM simulations. The results obtained demonstrate that this 4 ABHs + 4DVAs configuration effectively suppresses three resonances below the cut-on frequency while maintaining superior vibration attenuation above this threshold.