微穿孔介电弹性体薄膜的吸声性能试验分析*

针对普通薄膜型降噪结构的吸声性能较差和吸声带宽较窄的问题，本文设计了一种微穿孔的介电弹性体薄膜吸声结构。该结构由穿孔的介电弹性体薄膜与背腔组合而成，目的是拓宽介电弹性体薄膜低频率段的吸声带宽。针对微穿孔的介电弹性体薄膜吸声结构，从试验角度分析穿孔薄膜初始厚度、穿孔孔径及穿孔间距对结构吸声性能的影响。分析结果可知：通过适当增加薄膜的初始厚度，薄膜的整体吸声性能得到有效提升，最大可将319Hz吸声频带的吸声系数从0.2提升至0.7；减小薄膜的穿孔孔径能够有效拓宽穿孔薄膜的吸声频带，可使吸声系数0.4以上的吸声带宽由304Hz拓宽至432Hz；适当控制穿孔间距能够达到更好的吸声效果。

Experimental analysis of sound absorption performance of mic-perforated dielectric elastomer films

In response to the problems of poor sound absorption performance and narrow sound absorption bandwidth of general film-type noise reduction structures, a micro-perforated dielectric elastomer film sound absorption structure is designed in this paper. The structure consists of a perforated dielectric elastomer film and a back cavity, which aims to broaden the absorption bandwidth of the low frequency band of the dielectric elastomer film. For the micro-perforated dielectric elastomer film acoustic absorber, the effects of the initial thickness of the perforated film, the perforation aperture and the perforation spacing on the acoustic performance of the structure are analyzed from the experimental point of view. The results show that by appropriately increasing the initial thickness of the film, the overall absorption performance of the film can be effectively improved, and the maximum absorption coefficient in the absorption band of 319Hz can be increased from 0.2 to 0.7; reducing the perforation diameter of the film can effectively broaden the absorption band of the perforated film, and reducing the perforation diameter can broaden the absorption band of the absorption coefficient above 0.4 from 304Hz to 432Hz; proper control of the perforation spacing can achieve better sound absorption effect.