Analysis Of Sound Insulation Characteristics Of The Perforated Plate-Membrane Cavity Composite Acoustic Structure

The low-frequency noise generated during the operation of power equipment is difficult to be effectively controlled by the traditional acoustic structure due to its long wavelength,strong penetration ability and difficulty in attenuation.The proposal of acoustic metamaterials provides a new way to solve this problem,among which membrane-type acoustic structures have become a research hotspot in the field of low-frequency noise control due to their excellent characteristics of light weight,strong adjustability and easy implementation.Aiming at the problem of low-frequency noise sound insulation,this paper proposes a perforated plate-membrane cavity composite acoustic structure based on the membrane-type acoustic structure,and designs a membrane-type acoustic insulation enclosure with both good low frequency sound insulation performance and strong practicality.The research work carried out is as follows:The membrane cavity composite acoustic structure and the perforated plate-membrane cavity composite acoustic structure are proposed based on the membrane acoustic structure.The acoustic-vibration characteristics of the two structures are analyzed,and the influence of the structural parameters on their acoustic performance is explored by adjusting the structural parameters.Numerical studies show that the effective isolation of different frequencies of noise can be achieved by adjusting the structural parameters.The use of additional sound-absorbing materials and multilayer membrane can further improve the sound-absorbing performance and broaden the sound-isolation band.The acoustic performance of the perforated plate-membrane cavity composite acoustic insulation plate was studied in depth,and a numerical model of the acoustic vibration characteristics of the multi-cell element specimen was established to compare the acoustic vibration characteristics of the multi-cell element specimen with those of the unit-cell element structure,and it was found that the frame vibration caused a significant decrease in the acoustic insulation performance of the multi-cell element specimen.The acoustic vibration characteristics of the multi-cell combination structure were analyzed,and the structural parameters were adjusted to optimize the acoustic performance of the multi-cell combination structure.Then,the influence law of the frame parameters of the sound insulation panel on its sound insulation performance was systematically studied,and the sound insulation performance of the panel was improved by replacing the backing plate,attaching sound-absorbing materials,using multiple mass combination structures and designing multilayer-membrane-type sound insulation panels,which laid the foundation for designing a sound insulation panel with low-frequency broadband sound insulation performance and also provided the basis for the subsequent design of the sound insulation enclosure.The acoustic simulation model of perforated plate-membrane cavity composite acoustic insulation enclosure was established,the acoustic performance of different forms of acoustic insulation enclosure was analyzed,and the influence law of the number of membrane layers on the acoustic performance of perforated plate-membrane cavity composite acoustic insulation enclosure was studied.The numerical results show that the multilayer-membrane-type sound insulation can significantly broaden the sound insulation band and significantly improve the low frequency sound insulation performance,the three-layer membrane type acoustic insulation enclosure with additional sound-absorbing material significantly improves the sound insulation performance at the valley location,which shows that additional sound-absorbing material is an effective way to improve the sound insulation performance of the acoustic insulation enclosure and provides design methods and technical support for practical engineering applications.Finally,a perforated plate-membrane cavity composite acoustic insulation enclosure was designed as a physical model,and the acoustic insulation performance test of the perforated plate-membrane cavity composite acoustic enclosure was carried out.The results show that the trend of the simulation results is basically consistent with the experimental results,which verifies the correctness of the numerical model of the perforated plate-membrane cavity composite acoustic insulation enclosure established in this paper,and also indicates that the type of sound insulation enclosure has better sound insulation performance for low frequency sound waves,and has better sound insulation effect for specific frequency noise.