Study On Mechanical Properties Of Membrane-type Acoustic Metamaterial Plate

Metamaterial is a research focus in the international academia in recent years,,whose development history is just more than ten years. Metamaterial is a synthetic lcomposite structures or materials with some physical properties which conventionalmaterials do not have. Recently, metamaterials having developed are divided intotwo main categories: electromagnetic metamaterials and acoustic material. Acousticmaterials both have negative mass density and elastic modulus. Now for acousticmetamaterials,most studies have focused on one-dimensional pole structure, but infact2d or3d structures are more widely used.In this paper, study on mechanical properties of membrane-type acousticmetamaterial plate was conduct. Moreover, I was carried on the theoretical analysisand numerical simulation.In order to accurately determine the acoustic metamaterial mass density andbulk modulus, it is necessary to study on better viscoelasticity of rubber materials.The relationship between relaxation modulus and time was obtained by stressrelaxation test. Applying different viscoelastic constitutive model studied relaxationbehavior of rubber membrane materials, and found that the fractional constitutivemodel was more suitable for describing material performance of the rubbermembrane. Finally two important parameters of viscoelastic material weretheoretically calculated by choosing proper parameters: elastic modulus E andrelaxation time τ.The finite element analysis model membrane-type acoustic metamaterial platewas established, combining with vibration modal analysis of substructure cell, anddiscussed the selective filtering principle of two-dimensional acoustic metamaterialplate. Due to acoustic metamaterial plate having selective absorption, in the study ofacoustic metamaterial plate structure, only analyzing its vibration shape can beintuitive to get the work frequency of the acoustic metamaterial slab structure, andget the two-dimensional acoustic metamaterial plate optical frequency of vibration.The research provided reference for designing selective filtering material.Moreover,1d acoustic metamaterial structure model with damper wasestablished. The properties of metamaterial: the effective "negative" mass and bandgap were studied. Using the equivalent linear viscoelastic constitutive model provesthat the one dimensional system had a negative effective quality characteristics. Atthe same time, the relationship between the fractional order of constitutive modeland effective "negative" mass was discussed. Based on the principle of vibration absorber, acoustic band gap existing in the metamaterial structure was studiedthrough the frequency response function. Through the principle of local resonancephenomenon, the band gap in the frequency response function was analyzed. Theposition of the band gap having business with the frequency of the shock excitationand having nothing to do with the damp.In this paper, the acoustic metamaterial structure was studied on the basis of theprinciple of vibration absorber, which can realize the frequency selective filter, inareas such as damping, vibration isolation and stealth and have broad applicationprospects.