超薄金属纤维复合膜材料的低频吸声性能

本文针对限域空间（≤5mm）噪声防护对超薄吸声结构的重大需求，以不锈钢纤维毡为原料，利用低温烧结技术制备了由不锈钢纤维多孔材料和金属薄膜组成的复合膜材料。利用B&K声学测试平台对复合膜材料进行频率范围在50~1000Hz之间吸声系数的测试，分析了结构参数对复合膜材料吸声性能的影响规律。结果表明，通过分别研究金属纤维多孔材料的孔结构（孔径、丝径、烧结结点）及金属薄膜的层数对复合膜材料吸声性能的影响规律，发现在频率为50~1000Hz的范围内，超薄复合膜材料的最优结构为金属纤维多孔材料按照细丝径、小孔面向声源，粗丝径、大孔在后的顺序排列，材料内部复合铜箔可有效提高材料在低频处的吸声性能。

Lower frequency sound absorption of ultra-thin metal fiber complex film materials

In this paper, focusing on the exigent requirement of ultra-thin sound absorption structure in the limited space for noise treatment, the raw material was stainless steel fiber felt, the complex film materials composed with stainless steel fiber porous material and metal film were prepared by low temperature sintering technology. The sound absorption coefficient of complex film materials was tested by B&K acoustic test platform at the frequency range from 50 Hz to 1000 Hz, and the effect of structural parameters on the sound absorption performance of complex film materials is analyzed. The results shown as follows: the effects of pore structure of metal fiber porous materials (pore diameter, wire diameter, sintering node) and number of metal film layers on the sound absorption performance of complex film materials were studied. It is found that in the frequency range of 50 Hz to 1000 Hz, the optimal structure of ultra-thin complex film materials is that the arranged order of the porous metal fiber material is fine wire diameter, small pore facing to sound source, thick wire diameter and large pore in the back. Complex copper-film inside the materials can effectively improve the sound absorption performance at low frequency.