Fibonacci-Array Inspired Modular Acoustic Metamaterials for Tunable Low-Frequency Absorption

A customized metamaterial tailored for a specific functionality holds significant appeal in practical applications, yet its alteration after the structure is established can be challenging. A novel design for Fibonacci-array inspired acoustic metamaterials is introduced, which are constructed using metamaterial bricks with unique physical mechanisms. This design aims to achieve multifunctional low-frequency sound absorption. The Fibonacci sequence arrangement flexibly modulates the coupling between metamaterial bricks, thereby improving energy-dissipating efficiency. Additionally, the strategic alignment enhances the wave-absorbing properties of the metamaterial, allowing it to demonstrate remarkable absorption effects across targeted frequency bands. By controlling the resonance effect of metamaterial bricks in intensive and sparse modes, the proposed design exhibited frequency-selective performance, resulting in three absorption peaks at 323, 687, and 1113 Hz, respectively, across low- to high-frequency ranges. Furthermore, the broadband absorption performance, characterized by strong coupling strength, enables continuous sound absorption over a low-frequency band from 290 to 440 Hz. This is supported by theoretical analysis, numerical simulations, and experimental results, showcasing the flexible modulation of the propagation characteristics of sound waves. Overall, this functionally actuated design dramatically enhances the tunability of the metamaterials and offers a promising avenue for multifunctional application in noise-control engineering. A novel design for Fibonacci-array inspired modular acoustic metamaterials is proposed, constructed from metamaterial bricks that feature unique physical mechanisms. This innovative design achieves exceptional broadband and frequency-selective sound absorption, significantly enhancing the tunability of the metamaterials. As a result, it opens up promising opportunities for multifunctional applications in advanced materials and noise control engineering. image