有限元法(finite element method,FEM)具有几何适应性强但随分析频率增加计算时间成本迅速增加的特性,而波函数法(wave based method,WBM)拥有收敛性好但几何适应性差的特性.为减小离散单元带来的误差和提高分析频率,采用基于声压和法向速度连续性条件实现有限元法和波函数法混合建模的混合(finite element-wave based method,FE-WBM).以车内声腔为例,建立了车内声腔的二维FE-WBM模型,实现了车内声学响应预测.FE-WBM模型与参考有限元模型的声压云图和响应点声压频响曲线对比的结果表明,FE-WBM模型与参考有限元模型的计算结果很好吻合,验证了混合FE-WBM的有效性.分别以模型自由度和CPU运行时间为自变量,以响应点相对误差为因变量,比较两种方法的收敛特性.结果表明,在相同误差水平下,FE-WBM模型在模型自由度和CPU运行时间方面较传统有限元都有明显的优势.%Finite element method (FEM) has strong geometric adaptability, but its computation time and cost rapidly increase with the rise of analysis frequency,while wave based method(WBM) has the characteristics of high convergence rate but poor geometric flexibility. In order to reduce the error caused by discrete elements and high analysis frequency,a hybrid finite element-wave based method(FE-WBM) is adopted,which mixes the model-ing of FEM and WBM based on the condition of continuity in both sound pressure and normal velocity.Taking the in-vehicle cavity as an example,a 2D FE-WBM model for interior cavity is established to predict its acoustic responses. The sound pressure nephograms and the frequency-response characteristics curves of the response point of FE-WBM model are compared with those of reference FEM model with a result showing the consistency between the calculation results with two models,verifying the effectiveness of hybrid FE-WBM. With the degree of freedom and CPU time of the model as independent variables respectively and the relative error of response points as dependent variables,the convergence characteristics of FEM and WBM are compared.The results indicate that at the same level of error,FE-WBM is obviously superior to traditional FEM in terms of the degree of freedom of model and CPU time.
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