一种小局域条件下微穿孔板吸声体吸声特性研究

Research on the sound absorption performance of microperforated panel absorber under small local conditions

在1 mm厚碳纤维增强树脂板材上制备规则圆形的微穿孔,以此为基础,制得一种夹芯微穿孔吸声体,利用阻抗管测试方法研究了小局域条件对该吸声体吸声特性的影响。试验结果表明,小背腔的加入对该吸声体的微穿孔吸声效果有强烈影响,使其微穿孔的吸声频率向高频移动、吸声系数降低;且在该情况下,未发现组合微穿孔的协同吸声效应;基于声电类比法的微穿孔吸声方程可能不适合直接用于该声学结构吸声特性的预测、设计。利用亥姆霍兹吸声公式等声学理论,形成了一种适用于该小局域条件下夹芯微穿孔吸声体的计算方法,可解决该吸声体结构参数的设计问题,为优化其吸声特性提供依据。

The micro-perforation is successfully made on the 1 mm thick carbon fiber reinforced resin sheet. Based on this, a sandwich micro-perforated absorber is prepared. The influence of local condition on the sound absorption of this absorber is studied by the impedance tube test method. The results show that the addition of small back cavities has a strong inhibitory effect on the sound absorption of micro-perforation, and the sound absorption frequency of micro-perforation is shifted to high frequency region and the sound absorption coefficient is reduced. In this case, there is no synergetic sound absorption of micro-perforation. The electro-acoustical equivalent circuit model might not be applied to predicting and designing the sound absorption characteristics of this absorber. Based on the acoustic theory such as Helmholtz sound absorption method, a method of calculating the sound absorption characteristics of micro-perforation under small local conditions is established, which could solve the structural design problem of sandwich micro-perforated absorber with small back cavities, and prepare for the next step to optimize the structure of such absorbers.