为了对低声压级、低频带声波达到理想的吸收效果,提出了一种金属片镶嵌薄膜的复合吸声结构.分析了复合结构局域共振机理:通过薄膜材料的弹性波与每个结构单元的共振特性相互作用,可以产生局域共振带隙,从而使薄膜中的行波不能进行传播.利用传递矩阵法计算了镶嵌结构与薄膜空腔结构结合后的声阻抗,得到理论的吸声系数.通过试验得到复合结构中结构单元和薄膜的阻尼系数与弹性系数,对复合结构进行吸声系数测试,与理论计算值进行对比,理论计算结果与试验吸声系数吻合较好.采用薄膜两侧镶嵌结构单元与一侧的进行试验比较,得到两侧镶嵌结构的吸收峰值附近频带较宽,一些吸声系数达到0.95,实现了低频噪声的高效吸收.%To realize the ideal absorption effect on a low-decibel and a low-frequency band sound wave,a membrane structure inlaid with metal strips was proposed.The locally resonant mechanism of this complex structure was analyzed.It was shown that the interaction between elastic sound waves passing through membrane material and resonance characteristics of each structure unit can produce locally resonant band gaps,so the travelling waves in the membrane can't propagate.The sound impedance of the complex structure was calculated with the transfer matrix method to obtain the theoretical sound absorption coefficient.The damping coefficients and elastic ones of structure units and membrane in the complex structure were gained with tests.The sound absorption coefficient of the complex structure was measured.Through comparison,the tested sound absorption coefficient agreed well with the theoretical value.Finally,the test results using a complex structure inlaid with metal strips on both sides were compared with those using another complex structure inlaid with metal strips on one side,it was shown that the sound frequency band near the absorption peak of the former is wider,the sound absorption coefficient reaches 0.95 to realize the absorption of lower frequency noise with a higher efficiency.
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