Design Of Membrane-type Acoustic Metamaterial And Study On Acoustic Insulation Performance

Acoustic metamaterial is a composite material composed of special structural units and arranged periodically.It has extraordinary physical properties and has good application value in vibration and noise reduction.Based on the design of the membrane-type acoustic metamaterial structure,this paper improves the processing technology of the membrane-type acoustic metamaterial,and studies the sound insulation performance and its influence of the membrane-type acoustic metamaterial through numerical analysis,simulation calculation and experimental verification.The main tasks carried out are:(1)Study the sound insulation mechanism and the sound insulation performance evaluation index,and analyze the sound insulation characteristics of the membrane-type acoustic metamaterial by the finite element method.Based on the structure design of the membrane-type acoustic metamaterial,the processing technology of the acoustic metamaterial was studied and improved,and membrane with good consistency was obtained;(2)The self-vibration characteristics of the membrane-type acoustic metamaterial unit cell structure are studied,and the sound insulation is simulated and analyzed.Sound insulation measurement experiment of acoustic metamaterial samples by four-microphone method.Measurement experiments show that the acoustic insulation curve of the experiment and simulation is consistent at 10-800Hz;(3)Due to the verify factors affecting the sound insulation performance of membrane-type acoustic metamaterial,a method for evaluating the factors affecting sound insulation performance based on the hierarchical process is proposed.The factors affecting the sound insulation are membrane thickness,preload force and quality of the attached mass.The three factors are divided into three levels and the orthogonal scheme is used to design the simulation scheme for each level.The simulation results are analyzed through the orthogonal analysis method.It is found that when the membrane thickness is 0.14 mm,the preload force is 7N/m,and the additional mass is added for 0.30 g,the membrane-type acoustic metamaterial maximizes the sound insulation of 10-200 Hz noise;(4)Study the influence of different geometric parameters on the peak frequency of sound insulation.The following conclusions are drawn:(1)When the membrane thickness increased from 0.10 mm to 0.20 mm,the frequency corresponding to the other peaks of the first sound insulation peak is shifted to the low frequency direction,and the maximum offset is 176Hz;(2)When the preload force is increased from 3N/m to 8N/m,the frequency corresponding to the peak value of the first sound insulation is shifted to the high frequency direction,and the maximum offset is 216Hz;(3)When the attached mass is increased from 0.15 g to 0.90 g,the frequency corresponding to the peak of the first sound insulation is shifted to the low frequency direction,and the maximum offset is 36 Hz.