scholarly journals Investigation Of Sound Absorption Properties Of Bark Cloth Nonwoven Fabric And Composites

2015 ◽  
Vol 15 (3) ◽  
pp. 173-180 ◽  
Author(s):  
Samson Rwawiire ◽  
Blanka Tomkova ◽  
Eulalia Gliscinska ◽  
Izabella Krucinska ◽  
Marina Michalak ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Epoxy Polymer ◽  
Nonwoven Fabric ◽  
Natural Fibre ◽  
Woven Fabric ◽  
Absorption Properties ◽  
Fibre Network ◽  
Exploratory Investigation ◽  
Absorbing Materials ◽  
Fibre Morphology

AbstractThe quest for sound-absorbing materials that are not only environmentally friendly, but also sustainable is the foremost reason for natural fibre-acoustic materials. Bark cloth is a natural non-woven fabric that is largely produced from Ficus trees. An exploratory investigation of bark cloth a non-woven material and its reinforcement in epoxy polymer composites has been fabricated and investigated for the sound absorption properties so as to find the most suitable applications and also to see whether bark cloth can be used in some applications in place of man-made fibres. Three types of material species were investigated with their respective composites. The fibre morphology showed bark cloth to be a porous fabric that showed promising sound absorption properties at higher frequencies. The sound absorption results of four-layer material selections of Ficus natalensis, Ficus brachypoda and Antiaris toxicaria bark cloth showed sound absorption coefficient of 0.7; 0.71 and 0.91 at f > 6400 Hz, respectively. The bark cloth reinforced laminar epoxy composites had reduced sound absorption coefficients, which ranged from 0.1 to 0.35, which was attributed to decreased porosity and vibration in the bark cloth fibre network.

scholarly journals Effect of Sodium Hydroxide (NaOH) Treatment on Coconut Coir Fibre and its Effectiveness on Enhancing Sound Absorption Properties

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Ida Norfaslia Nasidi ◽  
Lokman Hakim Ismail ◽  
Emedya Murniwaty Samsudin
Keyword(s):  
Sodium Hydroxide ◽  
High Frequency ◽  
Sound Absorption ◽  
Fibre Diameter ◽  
Fibre Surface ◽  
Natural Fibre ◽  
Constant Thickness ◽  
Absorption Properties ◽  
Coir Fibre ◽  
Fibre Morphology

Natural fibre has been conventionally and widely utilised as a sound absorber in order to replace the traditional synthetic absorber materials. In this study, coir fibre (CF) was prepared as an acoustic absorber and subjected to an additional surface treatment by using sodium hydroxide (NaOH) at various concentrations ranging from 1% to 8%. This was geared towards analysing the effect of alkalisation on the fibre morphology, diameter, and changes occurring in the CF functional groups, thus resulting in enhanced sound absorption properties. To this end, the fibre surface was analysed using a scanning electron microscopy (SEM) to study the surface morphology of treated and untreated CF materials, whereas the implementation of Fourier-transform infrared (FTIR) allowed an analysis of CF characterisation. The absorber sample was fabricated at a constant thickness of 45mm and a density of 0.4g/cm3 density prior to testing for the sound absorption coefficient (SAC) by using an impedance tube. The morphology of CF revealed the treated fibres to be free of impurities including lignin and hemicellulose layer, which were removed from their surface. This finding was supported by the peak changes observed on the FTIR spectra. Furthermore, the fibre diameter was reduced as the concentrations of NaOH increased. The results conclusively indicated that treated CF at the concentrations of 7% and 8% NaOH gained the highest SAC values across the low and high-frequency ranges, yielding an α coefficient average of 0.9 and above.

scholarly journals Effects of air gap, fibre type and blend ratio on sound absorption performance of needle-punched non-woven fabrics

2019 ◽  
Vol 14 ◽  
pp. 155892501984087
Author(s):  
Mlando Basel Mvubu ◽  
Rajesh Anandjiwala ◽  
Asis Patnaik
Keyword(s):  
Sound Absorption ◽  
Polyester Fibre ◽  
Natural Fibre ◽  
Woven Fabrics ◽  
Air Gap ◽  
Natural Fibres ◽  
Interactive Effects ◽  
Woven Fabric ◽  
Absorption Coefficients ◽  
Blend Ratio

This article reports a study on the effect of different natural fibres, their blend ratios and varying air gaps between a needle-punched non-woven fabric and polystyrene backing on the sound absorption coefficients of the needle-punched non-woven fabrics. These parameters as well as their interactive effects were studied by variance analysis. The air gap varied from 0 to 25 mm in 5 mm increments; three natural fibre types (agave, flax and waste wool) were used; each one blended with polyester fibres in three blending ratios. The univariate test of significance showed that all three parameters and two of the three two-way interactions effects on sound absorption coefficients were significant. Only two-way interaction effect between blend ratio and air gap on sound absorption coefficient was not significant. It was found that the sound absorption coefficients increased with an increase in air gap size up to 15 mm, after which they decreased slightly as the air gap was increased further to 25 mm. In addition, the non-woven fabrics produced from the blend of waste wool and polyester fibres achieved the highest sound absorption coefficients than those of the other two natural fibres, and generally, the sound absorption coefficients increased with the increase in polyester fibre content in each blend studied.

Development of Natural Fibre Non-Woven Materials’ Application as Car Interiors for Noise Reduction

2011 ◽  
Vol 332-334 ◽  
pp. 1531-1534 ◽  
Author(s):  
Ming Ma ◽  
Yuan Bai ◽  
Xiao Ming Qian
Keyword(s):  
Noise Reduction ◽  
Reference Point ◽  
Sound Absorption ◽  
Noise Control ◽  
Natural Fibre ◽  
Noise Sources ◽  
Absorption Properties ◽  
Vehicle Noise ◽  
Nonwoven Materials ◽  
Potential Market

This document mainly introduces the evaluation of vehicle noise, noise sources and noise control. The development of fibers used for noise reduction materials is described as well. Besides, it analyzes the advantages and the necessities of the natural fibre nonwoven materials applied for the noise control, illustrates the present research status and the factors that introduces the sound absorption properties of the natural fibre nonwoven composites used for noise reduction. The paper also gives some reference point for advice to the development of automotive nonwoven materials. it shows that natural fibre nonwoven materials have a huge potential market and worthy for scholars to make a further study.

Sound absorption property of PVA/PEO/GO nanofiber membrane and non-woven composite material

2019 ◽  
Vol 50 (4) ◽  
pp. 512-525
Author(s):  
Huan Liu ◽  
Baoqi Zuo
Keyword(s):  
Graphene Oxide ◽  
Polyvinyl Alcohol ◽  
Polyethylene Oxide ◽  
Sound Absorption ◽  
Woven Fabric ◽  
Nanofiber Membrane ◽  
Absorption Properties ◽  
Blend Films ◽  
Absorption Performance ◽  
Nanofiber Membranes

Blend films based on polyvinyl alcohol/polyethylene oxide (70/30 wt%) undoped and doped with different concentration of graphene oxide were prepared by spiral vane electrospinning. Characteristic properties of the blend films were investigated by using X-ray diffraction and scanning electron microscopy. The sound absorption performance of the compositions (nanofiber membranes and needle punched non-woven fabric) was tested by an impedance tube. The sound absorption performance of non-woven fabric has greatly improved after combining with thin nanofiber membranes. With addition of graphene oxide, the fibers were intertwined in a loop and form a network, the areal density and surface roughness of the nanofiber membrane are reduced. Composites containing polyvinyl alcohol/polyethylene oxide nanofiber membranes and composites containing polyvinyl alcohol/polyethylene oxide/graphene oxide nanofiber membranes exhibited different sound absorption properties in different frequency bands. When the fiber coefficient of variation was small, the average sound absorption coefficient of the composite material was high. However, composites containing both polyvinyl alcohol/polyethylene oxide and polyvinyl alcohol/polyethylene oxide/graphene oxide nanofiber membranes had similar sound absorption properties, and the average sound absorption coefficient was greater than that of polyvinyl alcohol/polyethylene oxide composites.

Sound absorbing properties of roller blind curtain fabrics

2016 ◽  
Vol 47 (1) ◽  
pp. 3-19 ◽  
Author(s):  
Oğuz Demiryürek ◽  
Hüsnü Aydemir
Keyword(s):  
Sound Absorption ◽  
Woven Fabrics ◽  
Woven Fabric ◽  
Sound Insulation ◽  
Effective Parameters ◽  
Absorption Properties ◽  
Regression Curves ◽  
Woven Structures ◽  
Absorbing Property ◽  
Coating Mixture

Roller blind fabrics are preferred and commonly used in home and office. In general, these fabrics are produced by coating the acrylic blended material, which is known by their ultraviolet properties, onto polyester woven fabrics. In this study, in order to characterize the sound insulation properties of roller blind fabrics, coating resin having different ratios of acrylic are applied onto different polyester woven structures. Sound absorption properties of these fabrics (front and back sides) are measured through dual microphone impedance tube and investigated by statistical analyses. Regression curves are obtained and optimum fabric properties on sound absorbing property have been suggested. As a result, acrylic content in coating material, fabric type, and viol structures occurred by coating process on the woven fabric are found as effective parameters on sound absorption properties of these fabrics. Increasing acrylic content in the resin up to 40% increases the sound absorbing value but further increasing this ratio yields sound reflection from the structure, in general. Optimum sound absorption and reflection values are provided with 40% acrylic rate in coating mixture.

Acoustic Absorption Characteristics of Closed Cell Aluminium Foam

2011 ◽  
Vol 110-116 ◽  
pp. 1145-1149 ◽  
Author(s):  
Joyjeet Ghose ◽  
Vinay Sharma ◽  
Surender Kumar
Keyword(s):  
Sound Absorption ◽  
Aluminium Foam ◽  
Absorption Property ◽  
Optimal Thickness ◽  
Absorption Properties ◽  
Test Conditions ◽  
Closed Cell ◽  
Absorbing Materials ◽  
Difficult Situations ◽  
Absorption Characteristics

Experimental investigation of sound absorption characteristics of aluminium foam is carried out under laboratory test conditions. The studies revealed that the developed aluminium foam have excellent sound absorption properties and is comparable with other sound absorbing materials. Excellent sound absorption property coupled with good mechanical properties makes this material ideal for sound absorption under difficult situations. Experimental results revealed that the thickness of the specimen affects the sound absorption properties of the material, and there exists an optimal thickness, at which sound absorption coefficient is maximum. Experimental evidence showed that presence of damaged cell edges, open and/or semi-open cells in the specimen surface, enhances the sound absorption capability of the material.

scholarly journals A Basic Study on the Absorption Properties and Their Prediction of Heterogeneous Micro-Perforated Panels: A Case Study of Micro-Perforated Panels with Heterogeneous Hole Size and Perforation Ratio

Acoustics ◽  
2021 ◽  
Vol 3 (3) ◽  
pp. 473-485
Author(s):  
Midori Kusaka ◽  
Kimihiro Sakagami ◽  
Takeshi Okuzono
Keyword(s):  
Sound Absorption ◽  
Prediction Method ◽  
Normal Incidence ◽  
Homogeneous Material ◽  
Absorption Properties ◽  
Basic Study ◽  
Absorbing Materials ◽  
Predicted Values ◽  
Different Diameters

Micro-perforated panels (MPPs) are one of the most promising alternatives to conventional porous sound-absorbing materials. Traditionally, the theory of the sound absorption properties of MPPs is based on the assumption that MPPs are a homogeneous material with identical pores at regular intervals. However, in recent years, some MPPs have not met these conditions, and although a variety of designs have been created, their properties and prediction methods were studied in only fewer works. In this paper, considering the wide variety of MPP designs, we made a trial production of heterogeneous MPPs, which are MPPs with holes of different diameters, and studied the prediction method applicable to these MPPs. We measured the normal incidence sound absorption characteristics of those MPPs, backed by a rigid backing and air-cavity in-between, in an impedance tube. The prediction method proposed in this work is to treat the heterogeneous MPPs as combinations of several homogeneous components, and to combine them after applying the existing theory on homogeneous MPPs to each component. As a result, except in a few cases, the measured and predicted values of the absorption properties agreed relatively well. We also found that the arrangement of the holes in the material and the depth of the back cavity affected the agreement between the measured and predicted results.

Sound-Absorbing Properties of Kapok Fiber Nonwoven Composite at Low-Frequency

2013 ◽  
Vol 821-822 ◽  
pp. 329-332 ◽  
Author(s):  
Xue Ting Liu ◽  
Li Li ◽  
Xiong Yan ◽  
Hui Ping Zhang
Keyword(s):  
Bulk Density ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Low Frequency ◽  
Polyester Fiber ◽  
Physical Parameters ◽  
Absorption Properties ◽  
Kapok Fiber ◽  
Absorbing Materials ◽  
Properties Of Composites

More and more concern for environmental problems has led public to use natural and environmentally benign sound-absorbing materials. In this study, the sound-absorbing nonwoven composites based on kapok fiber and hollow polyester fiber were developed and sound absorption properties of kapok fiber nonwoven composites were investigated in the low frequency region of 100-500 Hz using the impedance tube method. The poor sound-absorbing at low-frequency is one of the difficult problems that urgently need to be solved in fibrous sound-absorbing materials. The effects of physical parameters, including bulk density and thickness, and depth of back cavity on sound absorption properties of composites were studied. Increasing of the bulk density, thickness and depth of back cavity is contribute to improve sound absorption properties of composites at low frequency. The comparisons of kapok fiber with polypropylene (PP) fiber and hollow polyester fiber indicated that as a natural fiber, kapok fiber had a superior acoustical properties at low frequency.

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