Dipartimento di Ingegneria, Università degli Studi di Ferrara Via Saragat 1, 44122 Ferrara, Italy.
J Acoust Soc Am. 2013 Jul;134(1):285-91. doi: 10.1121/1.4807820.
This paper presents a description of the use of simplified numerical methodologies for the optimization of the low cut-off frequency of anechoic and hemi-anechoic chambers. The anechoic chamber is modeled as a cavity with proper surface impedance boundary conditions. First, the shape of the wedges is optimized by means of a minimization-based procedure of a finite element model of such elements in a "virtual" impedance tube for a plane wave field. An equivalent surface impedance of the wedges is determined from those data. An analytical procedure is then used to determine the complex reflection coefficient for spherical waves at oblique incidence. Finally, a complex image source approach is used to predict the sound field within the chamber. The methodology is applied to two anechoic chambers and the results are compared in terms of sound decay along fixed directions and surface pressure distributions.
本文介绍了简化数值方法在优化隔音和半隔音室截止频率方面的应用。该隔音室被建模为具有适当表面阻抗边界条件的腔体。首先，通过在平面波场的“虚拟”阻抗管中对这些元件的有限元模型进行基于最小化的过程，对楔形的形状进行优化。从这些数据中确定楔形的等效表面阻抗。然后，使用解析程序来确定斜入射球面波的复反射系数。最后，使用复镜像源方法来预测室内声场。该方法应用于两个隔音室，并在固定方向上的声音衰减和声压分布方面对结果进行了比较。
