多孔介质声学:从微观几何特征到宏观吸声性能

Acoustics of Porous Media: from Microscopic Geometric Structures to Macroscopic Sound Absorption Performances

纤维材料和泡沫材料作为传统的多孔介质在中高频段上具有良好的吸声降噪特性,常常作为建筑、汽车、航空、工业及环境噪声控制中的重要选用对象.然而其复杂的微观几何结构以及多变的宏观吸声性能一直受到众多学者的高度关注和不断研究.这些研究往往由吸声机理出发,基于声学中的第一性原理,进行微观和宏观等多尺度下的探索,以发现或构造新的结构使材料的吸声性能表现更优.论文梳理了从微观几何结构分析到宏观吸声特性的研究脉络,并展示了近一二十年的研究方向和相关成果.首先介绍了多孔声学材料的微观结构特点、可视化途径以及表征其结构的相关几何参数,其次回顾了声学模型的发展历史、从其建立到不断完善的一系列过程,接着归纳了决定其宏观声学性能的物理量并探讨了它们的物理涵义,同时简述了材料宏观特性的理论推导计算、数值仿真方法以及实验测量手段等,而后列举了相关经验拟合公式以关联微宏双尺度用于分析影响吸声性能的关键因素,最后对后续研究发展进行展望.

Conventional porous media such as fibers and foams have good sound absorption characteristics at mid and high frequencies. They are commonly used in the fields of construction, automobile, aviation, industry and environmental noise control. The complex microstructures and various macroscopic sound absorption properties of porous media have been highly concerned and studied by researchers. These studies are often based on the first principles in acoustics, usually start from the sound absorption mechanism, and explore scientific laws on the microscopic and macroscopic levels in order to discover or create novel structures with better sound absorption performances. This paper combs the studies from microscopic geometric structure analyses to macroscopic sound absorption characteristics, and exhibits the related research directions and achievements in the past one to two decades. The microstructure characteristics, visualization pathway, and geometric parameters are introduced. The history from establishment to improvement of acoustic models is reviewed. The physical quantities that determine the acoustic performance are summarized, and their physical meanings are discussed. The theoretical calculations, numerical simulations, and experimental measurements for the macroscopic properties are described and compared. The empirical fitting formulas associated with the relationships between micro and macro scales are listed, aiming to analyze the factors that affect the acoustic performance. The prospects are discussed.