Broadband noise reduction inside helicopter cockpit with acoustic black hole effect

被引：0
|
作者：
Wang X. [1 ]
Qin Y. [2 ]
Ji H. [1 ]
Lu Y. [2 ]
Qiu J. [1 ]
机构：
[1] State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing
[2] National Key Laboratory of Rotorcraft Aeromechanics, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing
来源：
Ji, Hongli (jihongli@nuaa.edu.cn) | 1600年 / Chinese Society of Astronautics卷 / 41期
基金：
中国国家自然科学基金;
关键词：
Acoustic black hole; Broadband; Cabin noise; Helicopter; Noise reduction;
D O I：
10.7527/S1000-6893.2020.23831
中图分类号：
学科分类号：
摘要：
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. © 2020, Beihang University Aerospace Knowledge Press. All right reserved.
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