铝纤维板共振结构声学特性的理论初析

铝纤维板与背后空腔组成的吸声结构具有明显的共振吸声特性。铝纤维板的声学参量,即相对声阻抗率ζ和等效厚度l与等效参孔率σ的比值,可由驻波管法测量的吸声系数频响曲线反演求得。南于铝纤维毡的材质均摊性,铝纤维板共振吸声结构不再可以看成“局部反应”的声学元件,在空腔内加置小间距的横隔板有助于提高结构的吸声性能。

Theoretical analysis on acoustical characteristics aluminum fiberboard

The absorbing structure made of an aluminum fiberboard and a cavity on its back has clear resonance absorption characteristics. The resonant frequency and amplitude are related to the cavity depth, surface density, degree of compression, and the mounting. Acoustical parameters of an aluminum fiberboard, relative acoustical impedance ζ and ratio of the equivalent thickness l with equivalent porosity, can be obtained through an absorption coefficient spectrum measured in a standing wave tube. In general, acoustical characteristics of an absorbing structure can be studied using the common theory based on a micro,perforated panel resonance absorbing structure. The aluminum fiberboard cannot be regarded as a "local reaction" material because of the even spread of the aluminum blanket. The absorption property can be improved when partitions close to each other are installed in the back cavity.