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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。
In order to improve the sound absorption effect of the micro-perforated plate structure, the sound-insulating film was made into a corrugated structure, added into the cavity of the micro-perforated plate, and subjected to a sound absorption test by using a standing wave tube method to test thirteen Sound absorption coefficient at 1/3 octave center frequency. The results show that the single sound-absorbing membrane fold structure has a certain sound-absorbing ability, and the height of the fold has a certain influence on its sound absorption capacity. The addition of the sound-absorbing membrane fold structure can effectively improve the sound absorption performance of the micro-perforated plate. When the height is 6 cm, the peak value of sound absorption increases from 0.733 to 0.977 before and after the folding, and the absorption bandwidth increases from 2 (800 Hz ~ 1 250 Hz) to 5 (400 Hz ~ 1 000 Hz) 1/3 octave The center frequency of the center frequency of the composite increased with the crest height increasing from 2 cm to 6 cm. The sound absorption coefficient of the composite structure increased significantly, the absorption band increased, and the absorption band shifted towards low frequency. When the crease height was 6 cm, Sound peak reached 0.977, close to full absorption. The preliminary study of the effect of acoustic film folds on the sound absorption performance of micro-perforated plates provides a basis for further theoretical calculation and practical application.