Solid Mechanics and Vehicle Conceptual Design

Broadband noise reduction inside helicopter cockpit with acoustic black hole effect

  • WANG Xiaodong ,
  • QIN Yifan ,
  • JI Hongli ,
  • LU Yang ,
  • QIU Jinhao
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  • 1. State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2. National Key Laboratory of Rotorcraft Aeromechanics, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China

Received date: 2020-01-13

  Revised date: 2020-04-13

  Online published: 2020-04-10

Supported by

National Natural Science Foundation of China (11532006,51775267); Natural Science Foundation of Jiangsu Province (BK20181286); The Equipment Pre-Research Foundation (61402100103); A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions

Abstract

Acoustic Black Hole (ABH) effect allows alteration of the phase velocity and group velocity of wave propagation in a structure by changing the impedance to concentrate the waves in local areas of the structure and dissipate energy with a little damping. With the advantages of high efficiency, light weight, and wide frequency, the ABH provides a new perspective for structural vibration and noise control, exhibiting strong potential and application prospects. To reduce the broadband noise inside helicopter cockpits, this paper presents two kinds of structural design schemes based on the ABH effect after considering noise sources and transmission paths. The coupling model of the helicopter cockpit is established using the finite element software. The vibro-acoustic characteristics are then analyzed, and the mechanism of the ABH induced cabin noise reduction is explained. The effect test and performance evaluation are carried out on the established experimental platform. Results show that the embedded ABH structure can effectively reduce the medium-high frequency noise inside the cockpit, while its insufficient performance on low frequency noise is compensated by the additional ABH structure, therefore widening the effective frequency band. The average noise level can be reduced by 3-10 dB in the one-third octave band after employing both the embedded ABH and the additional one. Moreover, the total mass is slightly decreased compared with the traditional structure. This research contributes to the application of ABH new technology to vibration and noise reduction of helicopter engineering in the future.

Cite this article

WANG Xiaodong , QIN Yifan , JI Hongli , LU Yang , QIU Jinhao . Broadband noise reduction inside helicopter cockpit with acoustic black hole effect[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2020 , 41(10) : 223831 -223831 . DOI: 10.7527/S1000-6893.2020.23831

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