羊毛纤维对薄微穿孔板吸声性能的影响

选择厚度为2 mm的薄微穿孔板,研究羊毛纤维穿入率、穿入量和穿孔率对微孔板吸声性能的影响。在100~1 600 Hz范围内,随着羊毛纤维穿入率和穿入量的增加,共振吸声频率均向低频移动,吸声频带都得到拓宽。当羊毛纤维穿入率从0%增加到100%时,共振吸收峰向低频移动了340Hz,频带拓宽346 Hz以上。当穿入量从0根增至160根时,共振吸声频率向低频移动340 Hz;当穿入量约为106根时,频带拓宽360 Hz以上,共振吸声系数为0.92。而当穿孔率为1%时,穿入羊毛纤维使最大吸声系数降低,吸声频带变窄;但随着穿孔率的增加,穿入羊毛纤维可以显著拓宽微穿孔板的吸声频带,共振吸声系数也随之增大。当穿孔率为6%时,穿入羊毛纤维前后,最大吸声系数从0.68增至0.97,共振吸声频率从1 158 Hz降至986 Hz,频带拓宽了674 Hz以上。穿孔率越大,羊毛纤维改善微穿孔板吸声性能的优势越显著。

Effect of Wool Fiber on Widening Sound Absorption Spectrum of Thin Microperforated Panel

The introduction of the full paper reviews a number of papers in the open literature and then,in its last paragraph,points out that the effect of wool fiber on widening sound absorption spectrum,touched upon in Ref.10 authored by NWPU researchers,is promising and is therefore worth further study by us in this paper.Sections 1 and 2 explain our research.Section 2 presents our research results and their discussion;its core consists of:(1) in the frequency range of 100～1 600 Hz,when wool fiber is infixed into all the pores of a thin microperforated panel(MPP) with thickness of 2 mm,the resonance absorption frequency moves toward lower frequency of about 340 Hz,its absorption coefficient is 0.87,and its sound absorption spectrum is widened above 346 Hz;the resonance absorption frequency moves to lower frequency of about 340 Hz when the number of wool fibers per pore is 160;(2) when it is 106,the frequency band is broadened to about 360 Hz and the absorption coefficient is 0.92;when the ratio of wool fiber infixation is 100% and the porosity ratio is 6%,the resonance absorption frequency and the absorption coefficient are 986 Hz and 0.97 respectively and the absorption spectrum is widened above 674 Hz.Our research shows preliminarily that the bigger the porosity ratio,the better the sound absorption spectrum of the MPP is.