针刺中空短纤非织造布层合涤纶增强橡胶基材料的吸声性能

测试分析了针刺中空短纤非织造布与四孔中空涤纶短纤增强氢化羧基丁腈橡胶基材料(HF材料)层合的双层和三层材料的吸声性能.结果表明:双层材料以非织造布为入射面时,呈现多孔吸声材料特性,整体吸声性能相比单一材料有所提升;以HF材料为入射面时,双层材料在中低频域的吸声性能显著改善,但中高频域的吸声性能下降.三层材料整体吸声性能...     

羊毛及其混合纤维非织造材料的吸声性能

为优化羊毛非织造材料的吸声性能,以羊毛、毛/涤、毛/麻3种纤维制备非织造材料。通过阻抗管对3种非织造材料的吸声性能进行测试,分析了声波频率在250-6 300 Hz范围内,材料的纤维种类、厚度和空腔深度对其吸声性能的影响。结果表明,3种样品的平均吸声系数均大于0.2,纯毛非织造材料的吸声性能略好于毛/涤材料与毛/麻非织造材料;通过增加材料厚度或设置空腔的方式均可提高材料全频段（尤其中低频段）的吸声性能,其中厚度对材料吸声系数的影响程度更大;从环保、材料价格、便于施工等方面考虑,以厚度为6 mm的毛/麻非织造材料作为吸声材料,并设置6 mm的空腔, 即可达到较为优异的低频吸声性能。     

丙纶基熔喷非织造材料吸声性能研究

以丙纶熔喷非织造材料为研究对象,通过阻抗管声学分析仪测试非织造材料的吸声性能,研究成核催化剂、中空涤纶短纤及涤纶熔喷非织造材料和丙纶熔喷非织造材料之间的组合结构对丙纶熔喷非织造材料吸声性能的影响.并通过分析其吸声系数的变化,探讨了提高丙纶熔喷非织造材料的吸声性能的途径.     

废弃羊毛吸声复合材料的制备及其性能

为解决废弃羊毛再生循环利用问题,开发吸声系数高且吸声频带宽的吸声材料,以废弃羊毛为增强材料,乙烯醋酸乙烯共聚物（EVA）为基体材料,通过热压法制备了废弃羊毛/EVA 吸声复合材料。选用传递函数法分析废弃羊毛/EVA吸声复合材料的热压温度、材料密度、废弃羊毛质量分数、材料厚度、后空气层厚度以及废弃羊毛的排列方式等对吸声系数的影响。结果表明：用最优工艺制备的废弃羊毛/EVA吸声复合材料在低中高频都有优异吸声性能;该材料的吸声性能在中低频区域表现突出,在1 000 Hz处吸声系数达到0.9,材料降噪系数达0.65,平均吸声系数为0.6,即该材料为高效吸声材料;为吸声机制声波入射材料内部激发振动,声能转化为动能及热能,使废弃羊毛/EVA吸声复合材料具有优异吸声性能。     

CPE/涤纶七孔短纤弹性体复合材料的吸声性能

以氯化聚乙烯（CPE）为基体,涤纶七孔短纤（SHPF）为增强体,制备了CPE/SHPF系列弹性体复合材料,并对其吸声性能进行了研究。结果表明这种材料在中频段具有较好的吸声性能。随着纤维质量比的增加,材料的吸声系数明显增加,当CPE/SHPF的质量比达100/25时,厚度为1㎜的复合材料在2500 Hz时的吸声系数达到0.364。为分析其吸声机制,对材料进行了动态黏弹性测试发现,该材料的吸声效果与材料的黏弹性关系呈负相关,这与正常情况相违背,说明另有影响其吸声性能的因素存在。对材料进行了力学性能测试发现,随纤维含量的增加,材料的力学性能获得极大的改善。研究认为CPE/SHPF弹性体复合材料是一种具有工程应用潜力的吸声材料。     

针刺非织造材料形态与组合结构对材料吸声性能的影响

利用驻波管测试方法研究了几种不同厚度、不同密度和两种不同类型的纤维材料及其组合结构的吸声性能。研究结果表明,材料厚度的单因子条件与材料的吸声系数呈正线性相关;随着材料体积密度的增加,中低频声波的吸声系数提高,而高频声波的吸声系数呈现先提高后降低的趋势;材料的组合结构对材料的吸声性能影响很大,由中空纤维制成的低密度非织造材料与高密度非织造材料组合,并将高密度非织造材料置于表面,该组合方式的材料其吸声性能明显优于其他几种组合方式的材料。     

玄武岩纤维吸声复合材料的制备及性能研究

以玄武岩纤维为增强材料,以EVA粉末为基体材料,通过热压黏合法制备玄武岩纤维吸声复合材料。通过正交实验分析,得出制备玄武岩纤维吸声复合材料的最优工艺条件为:玄武岩纤维长度10 mm,玄武岩纤维质量分数50%,吸声复合材料厚度10 mm,热压时间15 min,热压压力6 MPa。在最优工艺条件下,玄武岩纤维吸声复合材料在声源频率为500 Hz以下时,吸声系数小于0.3,吸声性能较差;当声源频率在500~2 000 Hz时,最大吸声系数可达0.8,吸声性能优异;当声源频率大于2 000 Hz时,吸声系数的变化趋于平缓,表现出更加优异的吸声性能。     

木棉纤维吸声材料的制备及性能

木棉纤维具有薄壁和大中空的独特结构,其吸声性能良好。以木棉纤维为增强材料,EVA(乙烯-醋酸乙烯共聚物)粉末为基体材料,采用热压法制备木棉纤维/EVA吸声复合材料。重点研究了木棉纤维/EVA复合材料的吸声系数与材料密度、热压温度、热压时间、木棉纤维质量分数、材料厚度和后空气层厚度的关系。结果表明,在材料密度0.101 g/cm~3、热压温度110℃、热压时间10 min、木棉质量分数40%、材料厚度2 cm、后空气层厚度4 cm时,木棉纤维/EVA吸声复合材料的平均吸声系数为0.46。该材料在低中高频都有优异的吸声性能,吸声频带较宽。     

玄武岩包芯织物的制备及吸声性能

针对玄武岩纤维集束性差且可纺可织性低的缺点,使用涤棉纤维与玄武岩纤维制备3种线密度的赛络包芯纱线,并测试其基础性能。分别使用3种纱线织制平纹、蜂巢2种不同组织的机织物,探讨不同材料、厚度及排列方式对于织物吸声效能的影响。结果表明:所纺不同线密度包芯纱的质量均良好稳定,不同材料中包芯玄武岩织物的平均吸声性能最好;玄武岩平纹织物叠加到厚度3 mm的吸声性能时良好,但随着厚度增加,中低频吸声系数稍有下降;将2种组织织物交替复合的方式形成不同梯度的多孔结构,可显著提高织物的吸声性能,低中频的平均吸声系数在0.2以上,高频吸声系数可达0.7。     

废旧羊毛非织造布的制备及其吸声性能

为研究废旧羊毛纤维非织造材料的吸声性能,利用非织造材料的生产工艺,以废旧羊毛纤维为主要原料,制备一种新型羊毛非织造材料。通过使用传递函数法和驻波管法,对羊毛非织造材料的吸声性能进行了测试,分析了声波频率为250-6300 Hz范围内,材料的厚度、密度和空腔深度对其吸声性能的影响。结果表明,羊毛非织造材料吸声性能优异,对高频的吸声性能优于低频;在中低声波频率,随材料厚度、密度和空腔深度的增加,其吸声性能越好。材料厚度和空腔深度是影响羊毛非织造材料吸声性能的主要因素;通过增加空腔深度提升材料的吸声性能,是较为经济合理的办法。     

废弃纤维吸声复合材料的制备及其吸声性能

针对废弃纺织纤维利用率不高的问题,采用共混-热压工艺,以废弃纤维为增强材料,以热塑性聚氨酯为基体材料,制备废弃纤维/聚氨酯复合材料。将废弃纤维/聚氨酯复合材料加工成穿孔板,并与废弃涤纶织物贴合,构成吸声复合材料。重点研究吸声复合材料中穿孔直径、穿孔板厚度、穿孔率及废弃涤纶织物层数四种结构参数对材料吸声性能的影响。结果表明,穿孔直径主要影响吸声材料的吸声系数峰值;穿孔板厚度、穿孔率和废弃涤纶织物的层数主要影响吸声材料的吸声频带范围。     

分层复合水刺/热风非织造材料的吸声性能研究

以水刺非织造材料、热熔纤网和热风非织造材料为原料,分层叠加,置于烘箱中热风加热,制得两层和三层复合非织造材料。对分层非织造材料的厚度、透气性、孔隙率以及吸声性能等进行测试,探讨各因素对材料吸声性能的影响。测试结果显示:随着非织造材料厚度增加,同一声波频率的吸声系数提高;单层非织造材料的吸声系数随声音频率的增大而提高;双层复合材料吸声系数随着热风非织造材料面密度增加而提高,最高吸声系数向低频段偏移,吸声频段拓宽,吸声系数随着频率增加呈先上升再下降的趋势;双层分层吸声材料选择孔隙率梯度从受声面开始由低到高排列,三层复合材料的孔隙率按照低—高—低排列,可获得较好的吸声效果。     

Sound-Absorption Properties of Kapok Fiber Nonwoven Fabrics at Low Frequency

In this study, the sound-absorption properties of kapok fiber nonwoven fabrics were investigated in the frequency region of 100–2500 Hz using the impedance tube method. The effects of physical parameters including fiber mixing ratio, bulk density, and thickness on sound-absorption properties of composites were studied. The comparisons of kapok fiber with polypropylene fiber and hollow polyester fiber indicated that as a natural fiber, kapok fiber had superior acoustical properties at low frequency. A new simple model had been developed to predict the sound absorption coefficient of kapok fiber nonwoven composites at low frequency.     

Acoustic properties of sound-absorbing polyester fabrics woven with thick staple and thin draw textured yarn for use in interior decoration

Environmental pollution in our daily life because of noise is an increasing public health concern. We designed and woven with staple- and draw-textured yarns, for sound absorbance purposes. For wefts and warps, two different thicknesses of the thick staple-yarn and thin draw-textured filament yarn were used. The prepared fabrics were classified in porous, medium, and dense, on the basis of their densities and air permeabilities, and the sound absorption coefficients of the fabrics were found to be linearly related to the air permeability. The sound absorption coefficient determined by the impedance tube method was higher for porous fabrics compared with that for dense fabrics in the high frequency region. By the reverberant field method, the sound absorption coefficients for all fabrics were highest in the low frequency region. Porous fabrics exhibited a shorter reverberation time and a higher sound absorption coefficient than dense fabrics owing to their good sound absorption property.     

Study on the effects of denier and shapes of polyester fibres on acoustic performance of needle-punched nonwovens with air-gap: comparison of artificial neural network and regression modelling approaches to predict the sound absorption coefficient of nonwovens

In this article, a comparative analysis of artificial neural network (ANN) and regression modelling approaches has been carried out to predict the sound absorption coefficient (SAC) of nonwovens plus air-gap at wide range of frequencies (50–6300?Hz). Needle-punched nonwoven fabrics were produced with different denier and cross-sectional shapes of polyester fibres to study their combined effect on acoustic performance of nonwovens. The surface area of fibres, specific airflow resistance and mean flow pore size of nonwovens were analysed to explain their sound absorption behaviour. Finer fibre nonwovens perform better than the coarser fibre nonwoven as sound absorber. The effective surface areas of fibres in the nonwoven structure greatly affects the SAC. Finer fibres will get aligned easily in z-direction compared to coarser fibres, facilitating formation of more tortuous channels in the fabric structure contributing damping of sound waves. It has been observed that ANN model predicts the SAC with high degree of accuracy than the regression model. The ranking of input parameters in predicting SAC of nonwovens was analysed. Both the models ranked frequency of sound is the major determinant for predicting SAC followed by specific airflow resistance of nonwoven fabric.     

Research on sound absorption properties of multilayer structural material based on discarded polyester fiber

Thermoplastic polyurethane was reinforced with discarded polyester fiber to develop excellent mechanical properties of fiberboard composites, by hot pressing and mixing method. The fiberboard was drilled and made as a perforated plate, which was then coupled with polyester fabric; so a multiple layer structural material with good sound absorption function was achieved. Sound absorption properties were studied by changing holes diameter, air cavity depth, and perforation ratio. Theoretical absorption coefficient was obtained through building analytical model and massive theoretical calculation. It was found that it has good agreement with the experimental results. Hence, the analytical model could be adopted to predict the sound absorption coefficient of multilayer structural composites.     

废弃秸秆/聚己内酯吸声复合材料的制备与性能

为提高废弃秸秆的利用率,拓宽其应用领域,以废弃秸秆为增强原料,聚己内酯为基体材料,通过热压法制备废弃秸秆/聚己内酯吸声复合材料.在热压温度为120℃,压力为10 MPa,热压时间为20 min的条件下,通过实验探究秸秆质量分数、复合材料密度、复合材料厚度、后置空气层厚度等参数对吸声复合材料吸声性能的影响.结果表明:当秸...