Acoustic Vibration Coupling Analysis Of Typical Train Plates And Noise Prediction In Passenger Compartment Under Air Acoustic Excitation

Noise control in the passenger compartment is the focus of continuous attention in train comfort design.The train body is composed of a variety of plate-beam structures,which showing complex and diverse vibration frequency response characteristics.The existing numerical algorithms for the vibration response and acoustic vibration coupling of various types of plate structures have high matrix dimensions and slow solution efficiency.Present indoor noise prediction relies on the key acoustic test parameters of the finalized rear panel structure of the train prototype,resulting in a decrease in design iteration efficiency.In this paper,typical plates such as transversely isotropic plates,anisotropic laminated plates,hollow sandwich plates in glass and doors of trains are taken as objects,coupled the finite element and statistical energy hybrid analysis method(FE-SEA),the high-efficiency solution of typical plate vibration response,acoustic-vibration coupling analysis,and full-chain analysis methods for noise prediction in passenger rooms are proposed.The main contents and innovations include:(1)To improve the efficiency and accuracy of vibration calculation of plate structures,a Jacobi-Ritz vibration solution method is proposed,which is applicable to the higher-order shear deformation theory(HSDT)of transversely isotropic plate structures and the coupled block method.Based on the theory of high-order shear deformation,the vibration model of transversely isotropic plate structure is established by Jacobi-Ritz method with Jacobi polynomial as basic function.Multi-blocks are used to characterize the structural energy of the plate,and artificial springs are implanted to characterize the connection conditions and boundary conditions among the plate blocks.The convergence of this method is analyzed and compared,and the forced vibration response of rectangular functionally graded plate under different boundary conditions is solved.The results show that this method is very close to the analytical solution,its accuracy is higher than that of the first-order shear theory.The coupled block method is used to accelerate the convergence of this method.Hence,the computational efficiency is greatly improved.(2)To solve the problem of how to use Jacobi-Ritz method to calculate the vibration of train profile plates,a Jacobi-Ritz vibration solution method based on the high-order shear deformation theory of anisotropic laminated plates and the coupled block method is proposed.The equivalent method of profile plates mechanical parameters is put forward.Therefore,the profile plates of floor,roof and side walls are equivalent to anisotropic laminated plates.The vibration analysis model is established by JacobiRitz method,and a simplified calculation method for solving the vibration problems of train profile plates is formed.The acceleration response of the forced vibration of a typical train profile plate is calculated.Comparing the results calculated by this method with the ones of analytical solution and other approximate solutions,the results show that this method has fast convergence and high precision,and can accurately obtain the average amplitude of the vibration response of profile plates,and solve the problem that this kind of plate structure is difficult to characterize when using simulation parameters in the statistical energy analysis(SEA)model.(3)Aiming at the problem of how to calculate the acoustic-vibration coupling in frequency domain of single-board structure by Jacobi-Ritz method,a Ritz-SEA method based on block mapping fast multipole boundary integral for single-board structure is proposed.In this method,the blocks of plate structure correspond to the blocks of multipole boundary integral collocation points.The accuracy of analysis results is ensured by combining Burton-Miller method with Chief(Combined Helmholtz integral equation formula)method.This method is used to calculate the sound transmission loss of train profile plate.It can quickly and accurately calculate the average acoustic energy of the coupled acoustic cavity,which can effectively filter the vibration frequency change caused by the random position of the solution point.It is suitable for the medium-frequency acoustic-vibration coupling solution of plates and shells.(4)Aiming at the problem of acoustic-structural coupling of hollow sandwich panels of windows and doors,a Ritz-SEA acoustic-vibration coupling algorithm based on block mapping fast multipole boundary integral for hollow sandwich panels is proposed.In this method,the influence of sandwich acoustic cavity on the energy transfer of structural acoustic vibration is considered,and the connection function is introduced to accurately simulate the energy transfer relationship of profile plate through layer-by-layer calculation,which is verified by compared to finite element method.The results show that the connection function is accurate and reliable in the frequency range with the overall modal number less than5.It is suitable for solving the acoustic vibration coupling problem of hollow sandwich plates.(5)To solve the problem of how to reduce the dependence on test parameters in FE-SEA calculation,a statistical vibration energy flow prediction method of train passenger room noise is proposed,which takes acceleration constraint calculated by Jacobi-Ritz method and sound insulation calculated by Ritz-SEA method as key input parameters.In this method,parameters are assigned to the typical profile board SEA subsystem by the profile plates equivalent method,the acceleration calculated by Jacobi-Ritz method of anisotropic laminated board vibration is used to constrain the board subsystem,and the sound insulation calculated by Ritz-SEA method is used as the connection assignment,which forming a full-chain calculation method of train passenger room noise.The indoor noise of a certain type of subway train with a working condition of 70 km/h in the tunnel is calculated.The results show that the average error of this method is kept within 3 d B with limited line test data,which is close to the accuracy of existing prediction methods.(6)Focusing on the problem that the deterioration of the boundary conditions of the plate structure leads to the change of vibration characteristics,an analysis method of the deterioration of the boundary conditions of the plate structure-the deterioration of local vibration and sound insulation-the deterioration of noise response in the train room based on the accelerated test is proposed.The performance deterioration characteristics of rubber materials are obtained by accelerated test,and the door vibration characteristics and sound insulation changes caused by the deterioration of door seals are studied.The indoor noise changes of the whole vehicle are obtained by parameter mapping,and the influence of the deterioration of the boundary conditions of the plate on the noise characteristics is analyzed from the time dimension for the first time.The vibration method of plate structure established in this paper provides the key input parameters for the analysis of vehicle noise characteristics,largely gets rid of the dependence of vehicle acoustic design on the test parameters of plate structure,and forms a complete set of simplified,economical and efficient prediction and analysis methods for indoor noise of trains.The comparison results show the reliability of this method.There are 93 figures,20 tables and 181 references in the dissertation...