Study On Vibration Characteristics Of Acoustic Metamaterial Sandwich Panel

With the in-depth study of vibration and noise reduction technology,more and more attention has been paid to the acoustic metamaterial structure.This kind of artificial periodic composite structure can achieve a series of properties such as negative equivalent density and negative equivalent bulk modulus,which are difficult to achieve by natural materials.It is these unique properties that open up a new era for the research of vibration and noise reduction.Among them,the acoustic metamaterial with local resonance can control the propagation of low-frequency elastic waves with small periodic elements.In this thesis,based on the current research status of acoustic metamaterial sandwich panel with local resonance,in order to open the low-frequency band gap of a specific frequency,a mass-beam resonator is designed.The resonator is periodically arranged in the sandwich plates,forming a new type of acoustic metamaterial sandwich panel structure,which realizes the control of vibration caused by low-frequency elastic wave propagation.The main contents of this paper are as follows:(1)A sandwich-like plate structure with mass beam resonators is proposed.The structure consists of resonators composed of periodically arranged beams and mass blocks and faceplates.At the same time,the calculation method of band gap structure is studied.(2)Based on the energy principle,the calculation formula of the band gap region of the sandwich plate structure with single degree of freedom and double degree of freedom is derived,and the band gap characteristics of the two structures are studied.It is found that the structure can obtain a specific low-frequency band gap.The parameters affecting the band gap are discussed respectively,and the regulation law of the band gap of the two structures is obtained,and the band gap region and resonance are found The parameters of the resonator are closely related to each other.The starting position and range of the band gap can be adjusted by adjusting the geometry of the beam in the resonator and the mass of the mass block,and the generation mechanism of the structural band gap is revealed.(3)The finite element method is used to analyze the frequency response of acoustic metamaterial sandwich plate structure with single degree of freedom and double degrees of freedom.The accuracy of the band gap range calculated by the theory is verified.The influence of damping on the band gap characteristics is considered in the finite element simulation.It is found that the damping in the structure can effectively reduce the peak value of the structural response and broaden the band gap the purpose of the project.(4)Through the design experiment,the correctness of the band gap calculation formula and the frequency response analysis results in the finite element simulation of the two kinds of acoustic metamaterial sandwich plate structures are verified,and the feasibility of the designed metamaterial sandwich plate structure is verified.