Numerical Simulation Study On Acoustic Absorption Performance Of Acoustic Coatings

Acoustic coatings has both military and civilian uses,and the exploration of its sound absorption mechanism not only has theoretical and academic value in the field of materials science and acoustics,but also has considerable practical application value to national defense security and people’s life.Based on the finite element analysis theory and the finite element software COMSOL,a set of finite element model is established to calculate the acoustic absorption performance of the acoustic coatings under atmospheric and pressurized conditions.For the dynamic Young’s modulus E required by the model calculation,the frequency curves of the matrix materials under different prestrains were obtained by using DMA experiment and the temperaturefrequency equivalent principle.For the dynamic Poisson ratio ν,the Poisson ratio frequency curves of matrix materials under different water pressure are derived by combining the measured acoustic parameters with the theoretical model.Then the model validity and the accuracy of input material parameters are verified by comparing the measured data of acoustic tube.Then,based on the model,the influence of dynamic mechanical parameters and structural parameters on the sound absorption performance of materials under atmospheric and hydraulic pressure was explored.Under atmospheric conditions,the influences of thickness,density,energy storage modulus,loss modulus,initial static Poisson’s ratio and Poisson’s ratio parameters on sound absorption performance of uniform solid structure and cavity structure are discussed respectively.It is found that a small change in Poisson’s ratio can cause a large change in the sound absorption coefficient on a macro level.This paper has conducted an in-depth exploration of this phenomenon and found that a small change in Poisson’s ratio can cause a large change in the reflection coefficient of the interface between materials and water,thus affecting the sound absorption performance.Under the hydraulic pressure condition,the Yeoh superelastic constitutive equation was selected to calculate the deformation of the acoustic coatings,and the dynamic mesh function of COMSOL software was used to directly import the deformed mesh configuration into the acoustic finite element model.For the cavity structure with large deformation under water pressure,a C program was written to customize material properties and assign corresponding dynamic mechanical parameter values at different strains for acoustic calculation.The calculation error increased with the increase of water pressure.Based on this model,the influence of various material parameters on the acoustic coatings performance under water pressure is explored.It is found that compared with normal pressure condition,the influence of material parameters on the water pressure resistance should be considered in the pressure condition.The initial static energy storage modulus and the initial static Poisson’s ratio play an important role in the water pressure resistance performance,thus greatly affecting the sound absorption performance of the material under water pressure.