多层板的隔声特性研究

应用转移矩阵的方法，就平面声波垂直入射的情况，对具有周期结构的无限大多层板的隔声特性进行了理论分析，并对结构不同的多层板的隔声特性进行了数值模拟．理论分析和数值模拟表明：与通常隔声用的单层或双层板相比，在保持面密度不变的条件下，采用多层板结构能够在某些频段使隔声性能有明显改善，尤其体现在中高频段，但低频隔声效果稍有减弱．另外，适当调节多层板的厚度和板间的距离，可以实现对不同频段的隔声效果有所侧重．采用分区域等厚度的多层板，即采用厚、薄板相结合的复合结构，可以兼顾低频隔声性能，同时提高多层板的中高频隔声效果．在隔声结构的总体面密度和板的空间分布保持不变的情况下，换用同类的不同隔声材料对隔声特性没有明显改变，但可以适当改变隔声结构的强度．在隔声结构的设计过程中，针对不同的噪声频谱，可以采用中介绍的方法来构造相应的多层板结构，达到特定的隔声要求．研究结果对轻薄隔声结构的设计具有一定指导意义．

A Study on Sound Insulation of Multiple Panels

Sound insulation is an important subject in noise control. The sound transmission performance of multilayer systems is of utmost importance for noise control in automobiles, aircrafts, buildings, and several other engineering applications. The system with low-weight thin structure and good sound insulation character is very useful in the sound insulation field, and it is one of the important objects which many researchers long for. In this paper, the transfer matrix method is used to study the sound transmission loss for normal incident sound in periodic infinite multiple panels, and simulations are given for multiple panels with different structures, respectively. Both theoretical analysis and numerical simulations show significant improvement of the sound insulation character of multiple panels in the range of mid to high frequency compared with that of double panels or single panel on the condition that the areal density of these insulation structures are the same. On the other hand, adjusting the structure of multiple panels can also increase sound insulation character in different frequency ranges. Distinct thickness panels can be used in the same insulation structure which can improve sound transmission loss in the mid to high frequency range but almost can not influence sound insulation character in the low frequency range. The numerical simulations also show that sound transmission loss can be altered slightly if we only change the material of the panel or fluid and maintain other conditions as before. In the procedure of insulation design, different panel structures can be used under different noise circumstances by using the method proposed in this paper. This will benefit the practical design of new low-weight thin sound insulation structure in noise control.