航空学报 > 2024, Vol. 45 Issue (6): 428901-428901   doi: 10.7527/S1000-6893.2023.28901

直升机声学超材料舱壁的低频多带隙降噪特性

王晓乐1(), 孙萍1, 顾鑫2, 赵春宇1, 黄震宇1   

  1. 1.上海交通大学 感知科学与工程学院,上海 200240
    2.航空工业空气动力研究院 气动噪声重点实验室,哈尔滨 150001
  • 收稿日期:2023-04-21 修回日期:2023-05-15 接受日期:2023-06-19 出版日期:2023-06-29 发布日期:2023-06-27
  • 通讯作者: 王晓乐 E-mail:lelemyworld@sjtu.edu.cn
  • 基金资助:
    国家自然科学基金(52003155);“新风向”联合创新项目

Low⁃frequency and multi⁃bandgap noise reduction characteristics of acoustic metamaterial⁃based helicopter sidewall

Xiaole WANG1(), Ping SUN1, Xin GU2, Chunyu ZHAO1, Zhenyu HUANG1   

  1. 1.School of Sensing Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China
    2.Key Laboratory of Aeroacoustics,AVIC Aerodynamics Research Institute,Harbin 150001,China
  • Received:2023-04-21 Revised:2023-05-15 Accepted:2023-06-19 Online:2023-06-29 Published:2023-06-27
  • Contact: Xiaole WANG E-mail:lelemyworld@sjtu.edu.cn
  • Supported by:
    National Natural Science Foundation of China(52003155);Joint Innovation Project of the Key Laboratory of Aeroacoustics

摘要:

针对直升机舱内500 Hz以下的低频噪声控制难题,在原有直升机舱壁结构基础上引入声学超材料设计范式,提出一类低频多带隙声学超材料结构。该声学超材料结构单元内部包含4个悬臂梁式共振结构,在各个共振结构的谐振频率处能够打开局域共振完整带隙。首先,建立声学超材料结构单元的有限元动力学模型,算例分析其能带结构特性并揭示多带隙形成机理。其次,开展声学超材料样件安装于小尺寸均匀平直板前后的法向入射传声损失试验与锤击激励振声试验,发现实测的隔声提高区和传递函数幅值衰减区均符合理论预测的带隙频率范围,从而验证了理论模型的正确性。最后,在混响室-全消声室测试环境中开展声学超材料样件附加于大尺寸曲面加筋壁板前后的扩散场入射传声损失试验与激振器激励振声试验,证明即便应用于复杂结构壁板,声学超材料的带隙频段仍然显示出很高的潜力来改善隔声性能和振声行为。研究工作旨在为采用轻薄声学超材料降低直升机舱内噪声提供思路和方法。

关键词: 直升机, 噪声, 声学超材料, 低频, 带隙

Abstract:

To address the issue of low-frequency noise control in helicopter cabins below 500 Hz, a design paradigm of acoustic metamaterials is introduced for the acoustic treatment of the original helicopter sidewall. In this study, a low-frequency multi-bandgap acoustic metamaterial structure is proposed. The unit cell of the pro-posed acoustic metamaterial structure contains four cantilever beam-like resonant structures, which can open local-resonant complete bandgaps at the resonant frequencies of each resonant structure. Firstly, the dynamic model of a unit cell was established based on the finite element method. Through a numerical example, the band structure characteristics were analyzed, and the physical mechanism for generating multiple bandgaps was revealed. Secondly, experiments including the normal incident sound transmission loss experiment and the hammer-excitation vibration experiment were carried out to characterize the acoustic performance of a small-size uniform flat plate before and after the acoustic metamaterial was applied. The measured sound insulation enhancement region and the transfer function amplitude decay region were found to be consistent with the theoretically predicted bandgap frequency range, thus verifying the correctness of the theoretical model. Finally, in a reverberation chamber and full anechoic chamber test environment, the diffuse-field incident sound transmission loss experiment and the shaker-excitation vibration experiment were conducted to evaluate the acoustic performance of a large curved reinforced sidewall equipped with and without the acoustic metamaterial. It demonstrates that even when applied to complex structures, the bandgap effect of the acoustic metamaterial still shows high potential to improve the sound insulation performance and the vibroacoustic behavior of the original structures. This work aims to provide ideas and methods for reducing noise in helicopter cabins using ultrathin and lightweight acoustic metamaterials.

Key words: helicopter, noise, acoustic metamaterials, low frequency, bandgap

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