Topology Optimization Of Damping Layer Of Composite Plate Structure Based On Vibration And Acoustic Characteristics

The plate structure is light in weight and fast in heat dissipation,and is applied to various industries in the field of industrial manufacturing.At the same time,the vibration and noise problems caused by low rigidity and small damping cannot be ignored.With the continuous development of vibration suppression and noise reduction measures,surface damping treatment has become one of the mainstream methods.The main content of this paper is the influence of the free damping layer parameters and topology of the composite plate structure on the structural modal characteristics and acoustic radiation characteristics.The research object of this paper is a rectangular composite plate.The complex modulus model is used to describe the constitutive relation of the viscoelastic material of the free damping layer,and the finite element analysis model based on MATLAB is established.The modal loss factor is calculated according to the modal strain energy method,and the radiated sound power is calculated from the Rayleigh integral.Then compare the results with the calculation of commercial finite element software COMSOL and Virtual.Lab,to verify the correctness of the model for further research.In the research of damping layer parameters,the influence of the thickness of viscoelastic material and material loss factor on the modal frequency,modal loss factor and acoustic radiation power of the structure is analyzed,which provides a reference for the design and development of viscoelastic material parameters of composite plates.In the optimization of damping layer topology,the parameterized level set method based on GSRBF interpolation is used to optimize the shape and topology of the viscoelastic material distribution of the free damping layer.Compared with other topology optimization methods,this method can obtain smooth boundaries without relying on mesh density.Compared with the traditional level set method,this method is simple to calculate and less dependent on the initial design.In this paper,the optimization model aiming at the modal loss factor is firstly established.The Lagrange multiplier is introduced to add the volume fraction constraint as an extension to the objective function.The variational method is used to analyze the sensitivity of the objective function and the evolution rate of the level set function is derived.Field,supplemented by a simple approximation re-initialization method to solve the problem of numerical instability.Finally,an example is used to verify the correctness of the calculation model.Then,a simplified "sound power" optimization method based on the sum of the amplitudes of the plate surface reverberation speeds instead of the sound power is proposed.The evolution velocity field is also calculated and the differential equation is solved.The simplified model is validated by numerical examples.The purpose of this paper is to investigate the influence of damping layer parameters and topology on structural modal characteristics and acoustic radiation characteristics,and establish a parametric level set optimization model suitable for the vibrating-acoustic performance development of viscoelastic damping materials,Providing a reference for the precise design of area and thickness in automobile industry.