Study On The Vibro-Acoustic Characteristics Of Elastic Plate Coupled With Acoustic Cavity Under Complicated Boundary Conditions

Elastic structure and sound cavity coupling system has a wide range of applications in the industrial areas such as construction,submarine sea,shipbuilding and so on,and its research on acoustic vibration characteristics is of great theoretical and engineering significance.In the study of complex boundary conditions and parametric studies,the acoustic and vibration characteristics of structural acoustic cavity coupling systems are discussed.The current numerical methods have some limitations.The research contents involved are not comprehensive.Based on this,Vibration characteristics of the coupled system are studied and the following research work is carried out:In this paper,we first use the three-dimensional Fourier series method to establish the mathematic model of acoustic properties of rectangular closed-cavity under different impedance boundary conditions.Due to the discontinuity of the derivative of the boundary space,some errors will be caused in the numerical calculation.The related auxiliary functions are introduced into the standard three-dimensional Fourier cosine series.The Lagrange function of the rectangular cavity system is established,and the Rayleigh-Ritz method is used to solve the problem.The modal and acoustic properties of the rectangular closed cavity under different impedance boundary conditions were analyzed.The finite element simulation(FEM)was carried out with the software Virtual.Lab.The results of the two methods were compared to verify that the rectangular closed cavity Correctness of the model.Then,a single elastic plate-acoustic cavity acoustic vibration model was established.The three-dimensional improved Fourier series method is used to establish the displacement of the structure and the distribution function of the internal acoustic cavity in the single plate-cavity coupling system with different elastic constraint boundaries.The artificial virtual spring is introduced at the boundary of the structure.By changing the boundary Spring stiffness value,to achieve the different structure of the border settings.Combining with the principle of energy,the motion equation of the whole structure-cavity coupling system is described,and then the equation of motion equation of the coupled system is obtained by Rayleigh-Ritz method.By comparing with FEM simulation results,the correctness of the analysis model is verified.Secondly,a three-dimensional improved Fourier series method was used to build the upper and lower bouncing plate-cavity coupling system analysis model under complex boundary conditions.Numerical examples are given to verify the correctness of the analytical model.Then,an up-and-down double plate-cavity coupling system model under multi-point support boundary conditions is established.The acoustic-acoustic response of the coupled system is studied and compared with FEM simulation results to verify the correctness of the multi-point support system model.At the same time,a parametric study was carried out.Finally,the acoustic-vibration characteristics analysis model of the elastic plate-cavity coupling system based on Winkler-Pasternak elastic foundation is established.The Winkler-Pasternak elastic foundation is introduced into the boundary of the elastic plate structure.The numerical simulation is compared with the FEM simulation results.The correctness of the model is verified.Then the influence of the acoustic vibration characteristics of the single,upper and lower baffle-factor.In this paper,we get some conclusions and laws through the above research and have certain numerical reference value in the practical application of the project.