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阐述两子系统互易关系,给出混合FE-SEA法系统方程。利用该方法建立镁合金前围板隔声预测模型,与实验测试结果对比,验证隔声预测模型的可靠性。用FE-SEA法对隔声低谷处模态贡献量进行分析,找出关键参与模态,调取速度振型,识别出前围板声传递路径。通过改变多孔吸声材料及覆盖层厚度,参考降噪效率概念,研究混响声激励下两种典型声学包装ESP(Elastic-Sound Package)、FSP(Foam-Sound Package)在中低频段的TL发现,在260 Hz以下,覆盖层1 mm的ESP2效果最佳,大于260 Hz覆盖层1 mm的FSP2降噪最好。针对不同频段将两种方案用于前围板进行区域声学包装,隔声低谷得到明显改善,其它频段内隔声量提高约2 dB,表明声学包装方案设计可行,可为工程应用提供快、准的隔声措施。
Elaborating on the reciprocity between the two sub-systems, the mixed FE-SEA system equations are given. This method is used to establish the prediction model of sound insulation of magnesium alloy dash panel. Compared with the experimental results, the reliability of the noise prediction model is verified. FE-SEA method was used to analyze the modal contribution of the sound insulation valley to find out the key modalities of participation, to retrieve the velocity modes and to identify the sound transmission path of the dash panel. By changing the thickness of the porous sound-absorbing material and the thickness of the covering layer and referring to the concept of noise reduction efficiency, TL detection of two typical acoustic packages (ESP) and FSP (Foam-Sound Package) ESP2 at 1 mm coverage is best at 260 Hz and FSP2 at 1 mm coverage at 260 Hz is best. For different frequency bands, the two solutions are used for the area acoustic packing of the dash panel, the sound insulation trough is obviously improved, the sound insulation quantity in other bands is increased by about 2 dB, indicating that the acoustic package design is feasible and can provide fast and accurate Sound insulation measures.