隔声薄膜褶皱对微穿孔板吸声性能的影响

为提高微穿孔板结构的吸声效果,将隔声薄膜制作成褶皱结构,加入微穿孔板后空腔中,采用驻波管法进行吸声试验,测试在125 Hz到2 000 Hz的13个1/3倍频程中心频率处的吸声系数。试验结果显示:单独的隔声薄膜褶皱结构具有一定的吸声能力,褶皱的高度对其吸声能力有一定影响;隔声薄膜褶皱结构的加入能有效提高微穿孔板的吸声性能,当褶皱高度为6 cm时,加入褶皱前后,吸声峰值由0.733提高到0.977,吸声带宽由2个(800 Hz~1 250 Hz)提高到5个(400 Hz~1 000 Hz)1/3倍频程中心频率;随着褶皱高度从2 cm提高到6 cm,复合结构的吸声系数显著增加,吸声带宽随之增大,吸声频带朝低频方向移动,当褶皱高度为6 cm时,吸声峰值达到0.977,接近全吸收。试验初步研究了隔声薄膜褶皱对微穿孔板吸声性能的影响特性,为进一步的理论计算与实际应用提供一定根据。

Improvement of Sound Absorption Characteristics for Microperforated Panel Using Insulation Film Folds

Insulation film fold was added to the cavity of micro perforated panel(MPP)to improve the acoustical performance of MPP,and standing wave tube method was used to determine the sound absorption coefficients.Results showed that the insulation film folds structure has absorption capacity and the absorption effect of MPP can be significantly enhanced by adding the insulation film folds compared to single MPP structure.At the cavities’ height of 6cm,both acoustical absorption peak and absorption bandwidth can be increased,from 0.733 to 0.977 and from 2(800 Hz~1 250 Hz)to 5(400 Hz~1 000 Hz)one-third octave centre frequencies respectively,by setting the insulation film fold to the MPP’s cavity.Increasing in height of the folds led to a remarkably improvement of both absorption coefficient and absorption bandwidth of the composite structure,meanwhile the absorption range of composite structure move toward the low-frequency.