Development Of Vehicle Vibration And Noise Analysis Solver On The Basis Of Unstructured Elements

In the analysis of automobile vibration and noise,the finite element method is usually used to solve the problems of internal sound fiel d,sound radiation and structure-sound field coupling.Due to the existence of dispersion error,the finite element method makes its prediction results less reliable at medium and high analysis frequencies.Some of the current improved algorithms are still in the theoretical research stage,there are still many problems in the application of complex engineering problems,and professional finite element software has not been formed;at the same time,the current commercial finite element software market is b asically monopolized by foreign companies,in order to avoid similar The "Huawei Incident" appeared again,so it is particularly important to develop a self-developed and controllable acoustic finite element software.Therefore,based on the acoustic gradi ent weighted finite element method developed by the research group,this paper develops an unstructured grid-based vehicle vibration and noise analysis solver.The research results of this paper are as follows:(1)Based on the object-oriented programming design mode,an acoustic finite element software framework for the analysis of automobile vibration and noise was developed.The finite element analysis process is abstracted into five modules: file reading and writing module,data management module,numer ical model module,algorithm module and tensor and sparse matrix module.And realize the scalability,efficiency and security of the software framework through the class factory pattern and the singleton pattern.(2)A new method GW/PML based on acoustic g radient weighted finite element method(GW-FEM)and perfect matching layer(PML)is developed.The sound pressure gradient is reconstructed based on the gradient weighted finite element method and combined with the perfect matching layer,which effectively solves the problem of poor prediction reliability of the sound radiation problem in the middle and high frequency.The proposed GW/PML is used for existence analysis The frequency response analysis of the solution model shows that the prediction accuracy of the GW/PML method for the medium and low frequency sound radiation problem is significantly better than that of the finite element method.And through GW-FEM analysis of the frequency response of the sound field model in the car passenger cabin,it is proved that GW-FEM has broad application prospects in practical engineering problems.(3)Aiming at the problem that the traditional acoustic-structure coupling analysis method based on finite element is only suitable for low-frequency analysis due to the large dispersion error,a coupled acoustic gradient weighted finite element method and a plate-shell element based on the discrete shear gap at the center point are developed.Accurate and efficient new sound-structure coupling analysis method GW/CPDSG.Based on the gradient weighted finite element method and the center point discrete shear gap method,the coupling equation of the system is finally established through the compatibility and equilibrium conditions of the acoustic field and the structural field at the coupling interface.The established coupling model is applied to the analysis of the frequency response of the acoustic-structure coupling system in the car passenger compartment.The numerical results show that the prediction accuracy of the GW/CPDSG method for the mid-low frequency acoustic-structure coupling problem is significantly higher than that of the FEM/FEM coupling method.effectively improving the prediction accuracy of medium and high analysis frequencies,and has broad engineering value.