Acoustic absorbers based on single-order resonant mode of the resonators have been extensively investigated for low-frequency broadband absorption. However, they are usually limited to a certain range of working frequency bands and often do not work effectively in the high frequency range. Here, we present an acoustic metamaterial, perforated panel with tube bundles (PPTB) combined with coiled-up cavity, which effectively expands the operating bandwidth from low to high frequencies by utilizing the multi-order resonances. The PPTB ensures the efficient low-frequency absorption effect though the adjustment of tube diameter and length. The coiled-up prolongs the propagation path of sound waves, thereby facilitating the excitation of higher-order resonance modes at high frequencies. The multi-order resonances mechanism of the metamaterial is revealed thoroughly by theoretical calculations and finite element simulations. The results show that at the first-order peak, the energy dissipation mainly occurs in the tubes, while for the high-order peaks, the energy dissipation of coiled-up cavity gradually increases. Moreover, this work introduces the coupled-mode theory to determine the reasonably structural parameters, which enables to achieve the desired leakage and loss factors simultaneously, maintaining the higher muti-order absorption peaks in a wide frequency band and providing the wider single-order absorption peak in high frequency range. Utilizing multi-order resonances, a broadband metamaterial supporting an average absorption coefficient above 0.93 within 300–3600 Hz and eliminating the tangible absorption dips is obtained, which is mutually verified by theory, simulation and experimentation. Owing to its lightweight, less-complicated structure, terrific acoustic and mechanical performance, this kind of metamaterial may have a broad application prospect in noise control engineering.

中文翻译：

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通过多阶共振拓宽吸声带宽


基于谐振器单阶谐振模式的吸声器已被广泛研究用于低频宽带吸收。然而，它们通常仅限于一定的工作频段范围，并且往往不能在高频范围内有效工作。在这里，我们提出了一种声学超材料，带有管束的穿孔板（PPTB）与盘绕腔相结合，它利用多阶谐振有效地将工作带宽从低频扩展到高频。 PPTB通过调整管径和长度来保证高效的低频吸收效果。盘绕延长了声波的传播路径，从而有利于在高频下激发高阶共振模式。通过理论计算和有限元模拟，彻底揭示了超材料的多阶共振机制。结果表明，在一阶峰处，能量耗散主要发生在管内，而在高阶峰处，盘绕腔的能量耗散逐渐增大。此外，本文引入耦合模理论来确定合理的结构参数，从而能够同时实现所需的泄漏和损耗因子，在较宽的频带内保持较高的多阶吸收峰并提供更宽的单阶吸收高频范围内的峰值。利用多阶共振，获得了一种宽带超材料，其在300-3600 Hz范围内平均吸收系数高于0.93，并消除了有形的吸收下降，并通过理论、模拟和实验相互验证。 由于其重量轻、结构不太复杂、良好的声学和力学性能，这种超材料在噪声控制工程中可能具有广阔的应用前景。