Research On The Sound Absorption Performance Of Micro-perforated Plate Structure Based On Porous Materials

Micro-perforated plate sound absorber and porous material are typical sound absorption structures,which have the advantages of high temperature resistance,corrosion resistance and light weight,are widely used in buildings,ships,aircraft and other fields.However,the traditional single-layer micro-perforated plate structure has the shortcoming of narrow audio absorption band,especially under the condition of limited space,it cannot meet the sound absorption requirements.Porous material has the characteristics of sound absorption,shock resistance,energy absorption and heat transfer,etc.,when it is used as a multi-functional material,if the collapse deformation occurs,how the sound absorption characteristics of porous material change,and how does it relate to the amount of compression deformation.For this reason,this paper takes micro-perforated plate and sintered metal fiber porous material as the research object,and studies the acoustic absorption characteristics and mechanism of inclined micro-perforated plate structure,compressed porous material,and composite micro-perforated plate structure.The main research contents are as follows:Firstly,the equivalent depth expressions of cavities with different thickness in inclined micro-perforated plate structure are derived by using acoustic line method,and the acoustic impedance and absorption coefficient of inclined micro-perforated plate structure are calculated.The variation of acoustic resistance,acoustic reactance and acoustic absorption coefficient of inclined perforated plate structure with incident Angle of sound wave is studied,and the application of acoustic line method in acoustical structures with sound absorption is expanded.Secondly,taking the sintered fiber porous material as an example,the influence law of different compression ratios on the sound absorption characteristics of porous material was studied by experimental test method,and the changes of micromorphology and macroscopic size parameters of compressed porous material after the action of uniaxial testing machine were studied.The sound absorption characteristics of compressed porous materials were tested by means of impedance tub,and the influence mechanism of the compression ratio on the sound absorption characteristics of compressed porous materials is clarified.Finally,using the attached with a very thin thickness in micro perforation plate surface porous material,the method of micro perforation plate surface roughness is studied on the effect of sound absorption characteristics of perforated plate structure,analysis of the porous fibre diameter and pore diameter of porous materials,viscous flow resistance rate effect,and the complex structure of micro-perforated panel acoustic impedance and absorption coefficient variation law,and we at last reveal that the surface roughness of micro-perforated panel on the relationship between the structure of sound absorption performance.