微穿孔板声阻抗的直接准确测量

微穿孔板吸声结构的构造简单,适用范围广,吸收特性好并且可以比较准确地预计和设计。它的性能主要由微穿孔板的声阻和声质量决定。为了可靠地估计微穿孔板结构的性能,微穿孔板的准确特性是必要的。在本文中,作者提出直接测量微穿孔板声阻抗的简单方法（这方法也适用于一般穿孔板,或在一定范围内适用于一般吸声村料）,由于直接了当地分别测出声阻和声抗,不必经过任何转换,所得结果可达到比一般方法更为准确的程度。应用这个方法,对微穿孔板的阻抗特性进行了测量,得到线性和非线性的现象。在本文中,将报告一些初步成果。

DIRECT AND ACCURATE MEASUREMENTS OF ACOUSTICAL IMPEDANCE OF THE MICROPERFORATED PANEL

Microperforated panel absorption constructions are simple in construction, versatile in application, with good absorbing properties a nd afford prediction and design with relatively good accuracy. Their performance depands mainly on the acoustical resistance and mass of the microperforated panels. The exact properties of the microperforated panel, therefore, are necessary in order to estimate the performance of the microperforated panel construction reliably. In this paper, a simple and direct method of impedance measurements for microperforated panel (also suitable for ordinary perforated panels and in a limited sense for other absorbents) is proposed. Better accuracy is attained because of the straightforward nature of the resistance and reactance determination, avoiding the complex transformation of transcendental functions. When applied to actual panel, new light is shed on the nonlinear properties of the acoustical impedance of small apertures and microperforated panels. Preliminary results are presented.