基于湍流类比的金属橡胶吸声特性定量分析

金属橡胶材料从表到里都具有大量互相贯通且混乱的孔隙, 经分析认为, 这种混乱性及一定的周期性与湍流中的不规则性和准周期性极其相似. 由于金属橡胶材料内部芯材结构的不规则性, 即便此时的雷诺数很小, 波在金属橡胶中的传播仍是以湍流流动为主. 因此, 引入Kolmogorov的关于湍流的局部各向同性概念, 同时对Kolmogorov关于湍流局部各向同性的两个假设进行类比. 从湍流物理模型出发, 借鉴了湍流的统计处理方法, 对金属橡胶材料的吸声特性进行定量分析, 得到金属橡胶材料的能量耗散率与其结构参数之间的表达式. 研究结果表明, 湍流统计方法的引入, 为基于金属橡胶材料的减振器、阻尼器、消声器等的优化设计提供了可靠的理论依据, 也为超轻金属多孔材料的工程应用提供了一种有效的定量分析方法. 

TURBULENTLIKE QUANTITATIVE ANALYSIS ON THE SOUND ABSORBING CHARACTERISTICS OF METAL RUBBER

Metal rubber has much penetrated pores from the surface to the core,and the quasi-periodic and irregularity features are very similar to those of turbulence.Because of the irregularity within the structure of metal rubber,even if the Reynolds number is very small,turbulence still occurs.Therefore,the concept of the Kolmogorov local isotropic turbulence is introduced and two assumptions on the local isotropic Kolmogorov turbulence are obtained.The physical model of turbulence is established,and the sound absorbing characteristics of metal rubber are quantitatively analyzed and the relationship of the expression between the energy dissipation rate of metal rubber material and its structural parameters is obtained.The results show that the introduction of turbulence statistical method provides not only a reliable theoretical basis for the optimal design of metal rubber instruments such as damper and muffler but an effective quantitative analysis method for engineering applications of ultra-light metal porous materials.