Experimental Study Of The Performance Of Composite Sound-absorbing Structure In Aircraft Cabin

Huge noise not only is harmful for the members in the cabin, but may also damage theaircraft structure. So it is very necessary to take measures to reduce the noise. Layingsound-absorbing material in the noisy environments is a common way. The performance ofthe single material is relatively limited. So how to use the new structural form to utmostimprove the performance of the sound-absorbing material is a trend of the development ofsound-absorbing material in the future. The major work of this paper was to do experimentalresearch on composite sound-absorbing structure with new structural form, combininginorganic and organic materials, porous sound-absorbing material and resonancesound-absorbing material to study an effective solution for the low-frequency noise problemin the aircraft cabin.First, some single sound-absorbing materials were selected as the object of basic researchand the test specimen were prepared. In order to have complete control of the performance ofvarious types of sound-absorbing materials, the object of study covered interstitial closed-cellaluminum foam, open-cell foam aluminum and perforated aluminum of various aperture,glass fiber sound-absorbing cotton, polyester fiber sound-absorbing cotton, micro-perforatedabsorption film and aluminum foil. Standing wave tube method, varieties of sound-absorbingmaterial absorption coefficient were tested in the research to master the basic performance ofthe various types of sound-absorbing material. And the main factors of the sound absorptionproperties of various materials were analyzed, providing reliable data for subsequent work.On the basis of Porous sound-absorbing material theory, resonance sound-absorbingmaterial theory and impedance composite sound absorption structure theory, also with thedata of single sound-absorbing material, a variety of composite sound-absorbing structure wasdesigned, including the structure of new sound-absorbing materials or traditional and newabsorption materials. Low frequency sound absorption characteristics of the materialsdesigned were tested to explore the factors affecting the performance of sound-absorbingstructure and methods to improve its performance.The test results show: the sound absorption performance of composite sound-absorbingstructure in the research has significantly improved relative to the single sound-absorbingmaterials. With thin thickness, composite sound-absorbing structure had better sound absorption effect in the low frequency and has a wider sound absorption frequency domain.Sound absorption performance of the structure could be designed with a reasonable material,changing the order of the material layers, the material thickness, the cavity thickness, or otherfactors to obtain the structure to meet the actual demand.Finally, the article was summarized, the research results and short comings were analyzedand the outlook for the application of sound-absorbing structure was given.