Calculation of resonant sound absorption parameters for performance evaluation of metal rubber material

The first resonant (anti-resonant) frequency and sound absorption coefficient of metal rubber (MR) material are theoretically studied with hard backed samples and with air layer. The equations of the first resonant and anti-resonant frequencies of MR are deduced from the undamped propagation characteristics of porous material. The first resonant and anti-resonance sound absorption coefficients are induced according to the theoretical formula for the acoustic characteristic parameters of MR, and the former is modified while the energy consumption at resonance is taken into consideration. The good agreement between the calculation results of these resonant sound absorption parameters and the experimental results verifies the effectiveness of this calculation method for the performance evaluation of MR as a sound absorption material.     

金属橡胶材料单层结构吸声特性研究

从理论上研究了金属橡胶材料单层结构吸声特性。根据金属橡胶材料声学特性参数计算式,推导出两种基本单层吸声结构——置于刚性墙和带有空气层吸声结构的声阻抗率和吸声系数计算式。确定了流阻率是决定金属橡胶材料声学特性的基本参数。分析了材料厚度、流阻率及空气层厚度对两种吸声结构的吸声性能影响关系,建立了金属橡胶材料单层吸声结构第一共振频率的计算方法。结果表明：通过优化设计材料厚度、流阻率及空气层厚度可有效提高金属橡胶材料单层吸声结构的吸声性能。     

金属橡胶材料声学特性参数经验公式建立

研究了适用于恶劣环境吸声降噪需要的金属橡胶材料声学特性.根据纤维材料声学特性参数--特性阻抗和传播常数是频率与流阻率比值的幂函数关系的经验模型,通过试验研究建立了金属橡胶材料声学特性参数的经验公式.由声学特性参数经验公式计算了不同特征参数金属橡胶材料吸声系数,并与试验结果进行了比较分析.研究结果表明:建立的金属橡胶材料声学特性参数经验公式与材料实际结构特性符合较好,验证了采用该经验模型研究金属橡胶材料吸声降噪性能的有效性.