Study On Optimization Of Sound Insulation Performance Of Air Film Damping With Composite Structure

As a common engineering structure,plate is widely used in various fields.Air membrane damping technology is one of the passive control technologies for vibration and noise of plate structures.It not only has the advantages of simple technology,large structure damping,no environmental temperature,corrosion resistance and aging resistance,but also shows good performance in suppressing high-frequency vibration and noise of structures.In order to enhance its low and medium frequency sound insulation,based on the existing research results,this paper optimizes the sound insulation performance of the air film damping structure in the low and medium frequency band,The sound insulation characteristics of the two optimized air film damping structures and the influence of some structural parameters on the sound insulation performance are studied by using relevant theories and tools,so as to further enrich and optimize the research and application of air film damping technology in the field of vibration and noise of plate structures.(1)The FE-SEA mixed method model of sound insulation of air film damping structure is established.The internal loss factor of relevant panels is measured by free attenuation method.The sound insulation of the structure in 160 ～ 1000 Hz frequency band(1 / 3 octave analysis)is calculated and compared with the experimental results.The error is less than 10%,which verifies the reliability of the simulation model.(2)The FE-SEA hybrid simulation model of the structure with damping material on the additional plate is established and the sound insulation is calculated.Compared with the original structure,it is found that the sound insulation performance of the air film damping structure with damping material on the additional plate can be effectively improved in the middle and low frequency band.Based on this,the effects of different damping materials,laying thickness,laying rate and the number and interval of periodic damping blocks with the same area on their sound insulation performance are studied,and the relevant laws of the above parameters affecting their sound insulation performance are obtained.(3)Compared with the original structure,it is found that the sound insulation performance of the composite structure with holes on the additional plate is significantly improved,while the sound insulation performance of the composite structure with holes on the base plate is poor.Based on this,the influence of the hole diameter,the number of holes,the perforation rate,the different shape of holes and the different arrangement of holes on the sound insulation performance of the structure are studied,and the relevant laws of the above parameters on the sound insulation performance of the structure are obtained.(4)The sound insulation performance of two kinds of composite structure air film damping in middle and low frequency band was tested by reverberation chamber anechoic chamber method,and the reliability of the conclusion was verified.This study provides a basis for the design of air film damping sound insulation structure in low and medium frequency band,and has important engineering application value.