Study On Sound Insulation And Vibration Reduction Of Multi-mass Acoustic Metamaterial

As a new-type material with rapid development in recent years,acoustic metamaterial is expected to be widely used in various aspects such as noise control,vibration reduction and designing new waveguide devices.The research hotspot of acoustic metamaterial lies in designing a kind of acoustic metamaterial with simple structure and low cost to acquire better performance of so und insulation and vibration reduction.In order to push the multi-mass acoustic metamaterial into practical application,it is important to conduct in-depth research into the mechanism of sound insulation and vibration reduction of acoustic metamaterial,and combine finite element simulation with experimental test to study multi-mass acoustic metamaterial.Firstly,by establishing equivalent mass-spring model with damping force of membrane-type acoustic metamaterial unit,the effective mass density of acou stic metamaterial is confirmed to be negative at some specific frequencies.Based on the theory of plane wave propagation,the curve of transmission loss of membrane-type acoustic metamaterial unit in this paper is acquired by finite element method.In contrast to eigen-mode analysis and acoustic-structural analysis of membrane-type acoustic metamaterial unit,the best sound insulation frequency is attained.Changing the geometric parameter,number and distribution type of masses,the peak number of TL increases and the sound insulation at low frequency range is visible.Secondly,by analogy with the solving method of band structure of 2D phononic crystals and based on the Poisson theory of thin plate,the equation of longitudinal vibration band structure of 2D acoustic metamaterial plate is acquired by the plane wave expansion method.The curve of longitudinal vibration frequency response of 2D acoustic metamaterial plate is obtained by finite element simulation,which verifies the band gaps in the band diagram.When acoustic metamaterial plate is subjected to longitudinal excitation with different frequencies,it shows different vibration features.Designing particular acoustic metamaterial plate by changing the distribution type of multi-scatterer,which makes acoustic metamaterial plate own excellent performance in vibration reduction and the control of elastic wave.Finally,in order to verify the sound insulation and vibration reduction of acoustic metamaterial,the membrane-type acoustic metamaterial unit and 2D acoustic metamaterial plate are prepared.The curve of transmission loss of membrane-type acoustic metamaterial and the curve of longitudinal vibration frequency response of 2D acoustic metamaterial plate are obtained by sound insulation testing with 4206 impedance tube test system and vibration reduction experiment with vibration test platform respectively,the experimental results agree well with finite element simulation.The experiment validates the sound insulation and vibration reduction of acoustic metamaterial in this paper...