Design And Analysis Of Cyclotron Metamaterial Sound Absorption Structure

Noise has always been an important factor that disturbs people's work and life.Therefore,vibration and noise reduction is of great significance to improve people's life quality.Most sound absorbing materials and structures only have obvious absorption effect on medium and high frequency sound waves.But there is no significant absorption effect on low frequency sound waves.Therefore,the improvement of low frequency sound absorption has become a research hotspot for many scholars at home and abroad.In this paper,a rotary metamaterial acoustic absorption structure is designed based on curl acoustic metamaterials.The structure has good absorption effect on low frequency sound waves.Different from the traditional sound absorption structure,this structure mainly extends the transmission path of sound waves and uses friction and viscous forces to consume sound energy to achieve the purpose of low-frequency sound absorption.Firstly,based on the acoustic theory and the finite element simulation principle,the finite element model of rotary metamaterial structure is established.COMSOL Multiphysics software is used for simulation calculation to obtain the sound absorption coefficient curve.The correctness of the simulation method is verified by the reference model.Then,the variable control method is adopted to change the size parameters of the model.The effects of channel width,channel layer thickness and the number of channel layers on the acoustic absorption performance of rotary metamaterial are analyzed.The results show that the channel width and the number of channel layers have significant effects on the sound absorption performance of the structure.The influence of the thickness of the channel layer on the sound absorption performance is not obvious.Under different channel thickness,the sound absorption performance of the structure varies with the width of the channel.Finally,the porous material is applied to the rotary metamaterial to study the change of the sound absorption performance when the porous material is added to the channel and the substrate is made of porous material.The results show that the addition of porous material in the channel can significantly increase the structure's low-frequency sound absorption performance.When the flow resistance ratio is in the range of 1000~2000,the lower the flow resistance ratio of porous material,the better the low-frequency sound absorption ability.The addition of porous material to some channels is better than that of all channels.The sound absorption effect is best when the first layer is added with porous material.When addingporous material to one layer,different positions make different sound absorption performances.The farther the added porous material from the sound inlet hole,the better the sound absorption effect.When the substrate is all porous materials,the low-frequency sound absorption ability of the structure cannot be improved.When the channel layer is made of porous material,the low-frequency sound absorption ability is better than other conditions.