Simulation Of Sound Insulation Performance Of Elastic Closed-cell Foam Material

As a light material with good sound insulation performance,elastic closed-cell foam is widely used in the field of sound insulation and noise reduction.However,due to the high complexity of the internal cell structure of elastic closed-cell foam and the lack of an accurate theoretical model to predict its sound insulation performance,there is little research on its sound insulation performance in simulation.The simulation of this kind of material can save the experimental cost and obtain the design of cell structure with superior performance,which is of great significance for solving the sound insulation problem in engineering application.In this paper,the geometric modeling method and sound insulation performance of elastic closed-cell foam materials are studied as follows:In this thesis,the velocity parameters of all nodes on the surface of the model are obtained by harmonic response analysis,and then the root mean square of the surface vibration velocity is obtained.The relationship between vibration and acoustics is obtained by impedance matching method,so that the structural dynamics problem is transformed into acoustic problem,and then the acoustic performance parameters such as acoustic impedance and transmission coefficient of the material surface are obtained.In ANSYS,considering that the loss factor and damping of viscoelastic materials consume energy,they have similar effects,so we can choose the appropriate damping value by experience to solve the nonlinear problems.A suitable sample of elastic closed-cell foam was prepared by mature preparation technology,and its sound insulation performance and other physical parameters were tested experimentally.Compared with the elastic foam material without skin layer and the elastic closed-cell foam material with skin layer,the difference of sound insulation between them is 1.4d B,and the relative error is within 5%.Therefore,in this thesis,the equivalent model of the material without skin layer is established,and the random distribution of cells in the matrix is realized by RSA algorithm.Finally,the elastic closed-cell foam material model with random distribution of cells is established.Based on this model,the sound insulation performance of closed-cell foamed materials is studied and calculated by ANSYS simulation software.The results show that the curves are in good agreement in the frequency range of 50-1000 Hz,and the relative error between the experimental and simulation results is less than 5%.The finite element model has high accuracy and can be used to predict the sound insulation performance of elastic closed-cell foamed materials.Through modal analysis and resonance frequency calculation formula,it is verified that the sound insulation frequency curve has a sound insulation trough at 400 Hz due to the resonance of the material.Non-interactive execution files with different porosities and apertures are established by ANSYS simulation software,and the influence of them on sound insulation performance is studied.The results show that the sound insulation performance with porosity of 15% is better,and its weighted sound insulation is26.7d B;.And with the same porosity,the smaller the aperture,the better the sound insulation performance.On the basis of the above research,the influence of different material parameters on the sound insulation performance of materials is explored,and it is found that Poisson's ratio has the smallest influence on the sound insulation performance of materials.The damping will affect the resonant frequency of the material and the sound insulation at the resonant frequency.Young's modulus of the material has the greatest influence on the sound insulation performance.