Dynamics Modeling And Optimization Of Laminates With Sound Absorption Damp Layer

Porous medium material is a lightweight structure,which can effectively absorb impact energy,reduce noise,increase heat dissipation and heat insulation.So it is one of the effective materials for the sound absorption and noise reduction.Viscoelastic damping material is a composite material of high molecular polymer.By laying it on the surface of vibration structures can reduce the vibration well and it is a common material for the vibration reduction in engineering.Therefore,in order to obtain a better shock absorbing and noise reducing effect,the porous medium sound absorbing layer and the viscoelastic damping material are usually simultaneously laid on the structure.However,the layout design of the porous medium layer and the damping layer has a very important influence on the performance of the structure.Therefore,the establishment of the dynamic model with porous medium layer and damping laminated layer structure,and the research and optimization of its dynamic characteristics have certain engineering practical significance.The research work is mainly divided into three parts: the first part establishes the theoretical model of the porous medium plate and the base plate separately,and then integrate into a theoretical model of the laminated plate structure including the porous medium layer and the damping layer;the second part analyzes the vibration characteristics of the established theoretical model;the third part optimizes its structure by orthogonal experiment.First of all,based on the classical plate theory and threedimensional Biot theory,the first order differential control equations of the base plate and the porous plate is established.The normal interaction between each layer are elimited by virue of the normal equilibrium equation of the damping layer.Using the viscoelastic theory and shear Hooke’s law,the shear stress in the middle surface of the damping layer and its eccentric torque acting on the middle surface of the sound absorbing layer and the base plate are derived,and integrated dynamic control equation of the laminated plate covered damping layer and absorption layer are built.Combining with the boundary condition and precise integration method,a semi-analytical semi-numerical method for analyzing the dynamic characteristics of such laminated plates is proposed.On this basis,the dynamics response of the structure under the harmonic excitation are calculated by MATLAB software.Meanwhile,the equivalent media method is adopted to build the finite element model,and the analysis results has verified the proposed model.The effects of structural parameters and material parameters on the dynamic properties of the laminated plate with absorbent and damping layer are also analyzed.Finally,selecting the thickness of the damping layer,the thickness of the porous medium layer and the porosity as optimal parameters,and the best damping effect optimization goal,the structure is optimized by orthogonal experiment method.The modeling method,solution method and research results in this paper are expected to provide certain theoretical basis and technical support for the research and optimization of the dynamic characteristics of this type of laminated plate.