Evaluation of the acoustic and non-acoustic properties of sound absorbing materials using a three-microphone impedance tube

This paper presents a straightforward application of an indirect method based on a three-microphone impedance tube setup to determine the non-acoustic properties of a sound absorbing porous material. First, a three-microphone impedance tube technique is used to measure some acoustic properties of the material (i.e., sound absorption coefficient, sound transmission loss, effective density and effective bulk modulus) regarded here as an equivalent fluid. Second, an indirect characterization allows one to extract its non-acoustic properties (i.e., static airflow resistivity, tortuosity, viscous and thermal characteristic lengths) from the measured effective properties and the material open porosity. The procedure is applied to four different sound absorbing materials and results of the characterization are compared with existing direct and inverse methods. Predictions of the acoustic behavior using an equivalent fluid model and the found non-acoustic properties are in good agreement with impedance tube measurements. (c) 2010 Elsevier Ltd. All rights reserved.

本文介绍了一种基于三传声器阻抗管装置的间接方法的直接应用，用于确定吸声多孔材料的非声学特性。首先，采用三传声器阻抗管技术测量材料的一些声学特性（即吸声系数、声传输损失、有效密度和有效体积模量），此处将材料视为等效流体。其次，通过间接表征，可以从测量的有效特性和材料的开孔率中提取其非声学特性（即静态气流阻力、迂曲度、粘性和热特征长度）。该方法应用于四种不同的吸声材料，并将表征结果与现有的直接和逆方法进行了比较。使用等效流体模型以及所得到的非声学特性对声学行为的预测与阻抗管测量结果非常吻合。（c）2010爱思唯尔有限公司。保留所有权利。