Doutres O, Ouisse M, Atalla N, Ichchou M
GAUS, Department of Mechanical Engineering, Universite de Sherbrooke, Quebec J1K 2R1, Canada.
FEMTO-ST Institute, Department of Applied Mechanics, 24 rue de l'épitaphe, 25000 Besançon, France.
J Acoust Soc Am. 2014 Oct;136(4):1666-81. doi: 10.1121/1.4895695.
This paper deals with the prediction of the macroscopic sound absorption behavior of highly porous polyurethane foams using two unit-cell microstructure-based models recently developed by Doutres, Atalla, and Dong [J. Appl. Phys. 110, 064901 (2011); J. Appl. Phys. 113, 054901 (2013)]. In these models, the porous material is idealized as a packing of a tetrakaidecahedra unit-cell representative of the disordered network that constitutes the porous frame. The non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity, tortuosity, etc.) are derived from characteristic properties of the unit-cell and semi-empirical relationships. A global sensitivity analysis is performed on these two models in order to investigate how the variability associated with the measured unit-cell characteristics affects the models outputs. This allows identification of the possible limitations of a unit-cell micro-macro approach due to microstructure irregularity. The sensitivity analysis mainly shows that for moderately and highly reticulated polyurethane foams, the strut length parameter is the key parameter since it greatly impacts three important non-acoustic parameters and causes large uncertainty on the sound absorption coefficient even if its measurement variability is moderate. For foams with a slight inhomogeneity and anisotropy, a micro-macro model associated to cell size measurements should be preferred.
本文利用Doutres、Atalla和Dong最近开发的两个基于单胞微观结构的模型[《应用物理杂志》110, 064901 (2011); 《应用物理杂志》113, 054901 (2013)]，对高孔隙率聚氨酯泡沫的宏观吸声行为进行预测。在这些模型中，多孔材料被理想化为十四面体单胞的堆积，该单胞代表构成多孔框架的无序网络。经典的Johnson-Champoux-Allard模型中涉及的非声学参数（即孔隙率、气流阻力率、曲折度等）是从单胞的特征性质和半经验关系中推导出来的。对这两个模型进行了全局敏感性分析，以研究与测量的单胞特征相关的变异性如何影响模型输出。这有助于识别由于微观结构不规则性导致的单胞微观-宏观方法可能存在的局限性。敏感性分析主要表明，对于中度和高度网状的聚氨酯泡沫，支柱长度参数是关键参数，因为它对三个重要的非声学参数有很大影响，即使其测量变异性适中，也会在吸声系数上造成很大的不确定性。对于具有轻微不均匀性和各向异性的泡沫，应优先选择与泡孔尺寸测量相关的微观-宏观模型。
