【摘要】 探讨计算空腔结构吸声器吸声系数的方法。以粘弹体能量守恒方程为基础导出吸声器各层媒质的表达式,用声波在分层吸收媒质中传播模型计算能量吸收系数。用所导出的等效密度、弹性模量表达式和文献1[声学学报,1965;2(4):192-197]、文献2[同济大学学报, 1979(1):96-104]所给的等效参数,分别计算了尖劈吸声器和空腔结构的尖劈吸声器的吸声系数,比较表明对于前者三种方法都有效,对于后者本文的结果与实测吸声系数曲线较符合,另两文与实验相差较大;又用本方法分别计算了平板吸声器含空腔及空腔结构变化时的吸声系数,所得结果合理地反映了空腔结构对吸声性能的影响;对原空腔结构吸声器的吸声系数模拟结果作了实验验证,表明计算值和测量结果基本相符。结果表明用本文所给等效参量表达式和声波在分层吸收媒质中传播模型,近似计算空腔结构吸声器的吸声系数是可行的。更多还原

【Abstract】 An approximately calculating method for an absorption coefficient of sound absorber with cavity was studied. The energy conservation equation in viscous-elastic material, relations expressions between effective densities, elasticity modules of the every layers and the relevant quantities of the compounds of that layer were deduced. By using a model of sound propagation in absorb medium layers the energy absorption coefficient were obtained. The spectra of absorption coefficients of wedge-shaped sound-absorber were calculated using the relative expressions and in references 1 [Acta Acustica, 1965; 2(4): 192-197] and 2 [Journal of Tongji University, 1979(1): 96-104]. The calculated results shows that the three methods are effective for wedge-shaped sound-absorber; but for the wedge-shaped sound-absorber with cavities, the calculated results by the method put forward is closest to the experimental results among the three methods. As an example, the absorption coefficients of the plat sound-absorber with cavities were calculated. The simulated results can express the affection on absorption performance when the configuration of a cavity is changed, and are proved by experiments. An effective method which calculates absorption coefficients of sound-absorber with cavities is given.更多还原