Automobile interior acoustic field prediction method based on partition-of-unity finite element-meshless cell

Abstract

The invention discloses an automobile interior acoustic field prediction method based on a partition-of-unity finite element-meshless cell. The method comprises the steps of utilizing an automobile interior air acoustic cavity mesh model, defining the cell node support region of the automobile interior air acoustic cavity mesh model by use of the relation of a layer of connected nodes, constructing a local approximation function by use of a radial point interpolation method within the node support region of the automobile interior air acoustic cavity mesh model, and meanwhile, performing approximation by use of an isoparametric element shape function within the global mesh range of the automobile interior acoustic cavity, constructing a shape function and the gradient thereof at a Gauss integral point of the automobile interior acoustic cavity model in an isoparametric element integration manner, constructing the Galerkin weak-form of an acoustic equation of automobile interior acoustic cavity problems to obtain the system equation of the automobile interior acoustic cavity mesh model, thereby predicting the modal frequency and the mode of vibration of the automobile interior acoustic cavity, and meanwhile, predicting the acoustic response of the automobile interior acoustic cavity under the excitation of an engine and assessing the calculation results. The automobile interior acoustic field prediction method based on the partition-of-unity finite element-meshless cell is capable of obtaining better calculation results than a finite element method in the automobile interior acoustic cavity vibration noise prediction problem.

Description

technical field [0001] The invention relates to a prediction method for calculating the sound field inside an automobile, in particular to a method for calculating and predicting the sound field inside an automobile based on unit decomposition "finite element-meshless" units. Background technique [0002] At present, the prediction and analysis of the sound field of the car's interior acoustic cavity is an important task in the CAE (computer Aided Engineering, computer aided engineering) analysis of the NVH (Noise, Vibration, Harshness, noise, vibration and harshness) performance of the car body. It is very important to predict the NVH performance of the body and guide the development of NVH performance. [0003] At present, there are analytical methods and numerical methods for the simulation and prediction of the sound field in the car. The analytical method is generally only for simple problems and models; the numerical method is the current mainstream prediction method, ...

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Problems solved by technology

But this kind of method also has some problems. The finite element method has the acoustic numerical dispersion effect, and the prediction result is greatly affected by the size of the model grid and the calculation frequency. The system matrix of the boundary element method is asymmetrical and full, and the calculation efficiency is very high. Low, the calculation of the matrix is ​​complicated, and its application prospect is not as broad as that of the finite element method

[0004] In order to meet the reliability of the prediction results of the analysis of the vehicle's interior sound field, the automotive design engineer needs to check the mesh size and model quality during the modeling process, which requires a lot of pre-processing time and manpower. Therefore, there are It is necessary to invent some new forecasting methods to reduce the impact of the forecasting results on the quality of the model

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