含三聚氰胺多孔材料分层复合介质吸声特性*

三聚氰胺泡沫材料是一种具有高开孔率的多孔材料,具备优良的吸音、防火隔热及环保性能,可以作为吸声材料与弹性板、空腔介质形成复合结构,在建筑、航空、交通工具等工程领域有广泛的应用。该文基于Biot理论和分层介质在交界面处的不同边界条件,建立非均匀复合介质背衬刚性壁面结构的理论声学模型,详细分析了多孔材料布局对复合结构吸声特性的影响。该文理论模型计算的结果与阻抗实验得到的垂直入射吸声系数基本一致,验证了理论模型的正确性。结果表明:在多孔材料前面增加空气层可以改善高频吸声特性;在多孔材料后面增加空气层可以改善复合结构低频吸声特性。通过合理配置多孔材料,可以在应用需求频段上达到满意的吸声效果。

Sound absorption characteristics of layered composite material with melamine porous material

Melamine foam material is a kind of porous material with high open porosity. It has excellent sound absorption, fire insulation and environmental protection performance. It can be used as a composite structure for acoustic materials, elastic plates and cavity media, in construction, aviation, transportation, etc. The engineering field has a wide range of applications. Firstly, this paper establishes a theoretical acoustic model of a multi-layer composite media backing rigid wall structure based on the Biot theory and the different boundary conditions of the layered media at the interface. In this paper, the effect of the layout of the layered composite structure on the sound absorption characteristics are discussed in detail. Secondly, this paper establishes an impedance tube finite element model to simulation experiments process. The calculated normal incidence sound absorption coefficients are good agreement with the measured results. The results show that adding an air layer in front of the porous material can improve the high-frequency sound absorption characteristics. Adding an air layer behind the porous material can improve the low-frequency sound absorption characteristics of the composite structure. By reasonably configuring the porous material, satisfactory absorption can be achieved at the application frequency band.