scholarly journals Experimental and Modelling Studies on Thermal Insulation and Sound Absorption Properties of Cross-Laid Nonwoven Fabrics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tao Yang ◽  
Lizhu Hu ◽  
Xiaoman Xiong ◽  
Michal Petrů ◽  
Sundaramoorthy Palanisamy ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Absorption Coefficient ◽  
Thermal Insulation ◽  
Sound Absorption ◽  
Nonwoven Fabric ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Nonwoven Fabrics ◽  
Significant Difference ◽  
Modelling Studies

Abstract Nonwoven fabrics are widely used for thermal insulation and sound absorption purpose in construction and automobile fields. It is essential to investigate their thermal conductivity and sound absorption coefficient. Five cross-laid nonwoven fabrics are measured on the Alambeta device and Brüel & Kjær impedance tube. Bogaty and Bhattacharyya models are selected to predict the thermal conductivity, and Voronina and Miki models are used to predict the sound absorption coefficient. The predicted thermal conductivity shows a significant difference compared with the measured values. It is concluded that Bogaty and Bhattacharyya models are not suitable for high porous nonwoven fabric. In addition, the results of Voronina and Miki models for sound absorption prediction are acceptable, but Voronina model shows lower mean prediction error compared with Miki model. The results indicate that Voronina model can be used to predict the sound absorption of cross-laid nonwoven fabric.

The Primary Study on Polyester/ Polypropylene Sound-Absorption Nonwoven Fabric

2012 ◽  
Vol 554-556 ◽  
pp. 136-139 ◽  
Author(s):  
Chen Hung Huang ◽  
Ting Ting Li ◽  
Yu Chun Chuang ◽  
Ching Wen Lou ◽  
Jin Mao Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Nonwoven Fabric ◽  
Low Noise ◽  
Primary Study ◽  
Maximum Tensile Strength ◽  
Nonwoven Fabrics ◽  
Tearing Strength

As social civilization advances, more and more people reside in the city. Consequently, the number of automobiles and locomotives increases, causing greenhouse effect and noise pollution increasingly serious. Therefore, lowering the temperature and reducing the noise in living conditions has become an urgent task, in order to save resources usage amount and to produce a low-noise dwelling environment. In this study, the sound-absorption and heat-insulation nonwoven fabrics were firstly prepared by three-dimensional crimp hollow polyester fiber (PET) fibers and Polypropylene (PP) fibers based on nonwoven processing technology, following by sound-absorption coefficient test, thermal conductivity test, as well as maximum tensile strength and maximum tearing strength tests. The results show that, 70/30 wt% PET/ PP nonwoven fabrics have the maximum tensile strength of 2.47 MPa (CD) and 1.67 MPa (MD), in addition with the maximum tearing strength of 83.96 kN/m (CD), 111.88 kN/m (MD); the 90/10 wt% PET/ PP nonwoven presents the lowest thermal conductivity coefficient of 0.0365 W/K‧m; nonwoven with three different ratios show the similar sound-absorbing curves, which all reaches the highest absorption coefficient of 0.76 at 4000 Hz.

scholarly journals Acoustic Panels Made of Paper Sludge and Clay Composites

2021 ◽  
Vol 13 (2) ◽  
pp. 637
Author(s):  
Tomas Astrauskas ◽  
Tomas Januševičius ◽  
Raimondas Grubliauskas
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Composite Panel ◽  
Sound Absorption Coefficient ◽  
Core Material ◽  
Paper Sludge ◽  
Frequency Range ◽  
Absorption Properties ◽  
Air Gaps ◽  
The Core

Studies on recycled materials emerged during recent years. This paper investigates samples’ sound absorption properties for panels fabricated of a mixture of paper sludge (PS) and clay mixture. PS was the core material. The sound absorption was measured. We also consider the influence of an air gap between panels and rigid backing. Different air gaps (50, 100, 150, 200 mm) simulate existing acoustic panel systems. Finally, the PS and clay composite panel sound absorption coefficients are compared to those for a typical commercial absorptive ceiling panel. The average sound absorption coefficient of PS-clay composite panels (αavg. in the frequency range from 250 to 1600 Hz) was up to 0.55. The resulting average sound absorption coefficient of panels made of recycled (but unfinished) materials is even somewhat higher than for the finished commercial (finished) acoustic panel (αavg. = 0.51).

Effect of Nanocellulose on Acoustical and Thermal Insulation Properties of Silicone Rubber Composite

2019 ◽  
Vol 964 ◽  
pp. 156-160 ◽  
Author(s):  
Mohammad Farid ◽  
Agung Purniawan ◽  
Diah Susanti ◽  
Amaliya Rasyida ◽  
Henry Yulianto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Absorption Coefficient ◽  
Silicone Rubber ◽  
Sound Absorption ◽  
Wide Band ◽  
Sound Absorption Coefficient ◽  
Empty Fruit Bunch ◽  
A Value ◽  
Rubber Composite ◽  
The Matrix

Nanocellulose composites are very potential to be applied as automotive component materials.The purpose of this research is to analyze the influence of nanocellulose fraction of the silicon rubber composite material to morphology, sound absorption coefficient, density, thermal stability, and thermal conductivity. The nanocellulose of the composites were isolated from oil palm empty fruit bunch, while the matrix was silicone rubber. Tests conducted in this research included sound absorption coefficient, SEM, TGA, density, and thermal conductivity. Sound absorption coefficient had a value between 0,33 to 0.42 for a frequency of 500 Hz to 4000 Hz. This sound absorption coefficient had a wide band sound absorption tendency and was developed for sound absorption material of mufflers.

Physical and Sound Absorption Properties of Spent Tea Leaf Fiber Filled Polyurethane Foam Composite

2014 ◽  
Vol 660 ◽  
pp. 541-546 ◽  
Author(s):  
Qumrul Ahsan ◽  
Chia Pooi Ching ◽  
Mohd Yuhazri bin Yaakob
Keyword(s):  
Absorption Coefficient ◽  
Polyurethane Foam ◽  
High Resistance ◽  
Sound Absorption ◽  
Filler Loading ◽  
Tea Plant ◽  
Sound Absorption Coefficient ◽  
Tea Leaves ◽  
Absorption Properties ◽  
Spent Tea Leaves

Spent tea leaves (STL) from tea producing factories can be considered as new resources for sound absorbing polyurethane (PU) matrix composite materials because STL are rich in polyphenols (tannins) which cause high durability, high resistance to fungal and termites, and high resistance to fire. The research aims to study the physical characteristics of STL and the effect of dispersion morphology of STL on the sound absorption properties of polyurethane foam composites by varying filler loading. Three grades of STL fibers either as received or granulated are used in this study, namely BM-FAE and SWBHE derived from the stalk while FIBER-FAE derived from the leaves of the tea plant. The PU/STL composites are fabricated through open molding method with a fiber loading of 16 wt. %. The fabricated composites are then subjected to physical and sound absorption testing as well as microscopic observations to analyze the distribution of filler in composite. The study shows that as-received FIBER-FAE spent tea leaves provide the best sound absorption coefficient and for composites using granulated fibers from any grade have lower sound absorption coefficient. These results show that a novel kind of sound absorption materials with the recycling of waste materials can be obtained for the solution of noise and environmental pollution.

scholarly journals Sound absorption properties of multi-layer structural composite materials based on waste corn husk fibers

2020 ◽  
Vol 15 ◽  
pp. 155892502091086
Author(s):  
Lihua Lyu ◽  
Jing Lu ◽  
Jing Guo ◽  
Yongfang Qian ◽  
Hong Li ◽  
...  
Keyword(s):  
Composite Materials ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Cavity Depth ◽  
Air Cavity ◽  
Corn Husk ◽  
Structural Composite

In order to find a reasonable way to use the waste corn husk, waste degummed corn husk fibers were used as reinforcing material in one type of composite material. And polylactic acid particles were used as matrix material. The composite materials were prepared by mixing and hot-pressing process, and they were processed into the micro-slit panel. Then, the multi-layer structural sound absorption composite materials were prepared sequentially by micro-slit panel, air cavity, and flax felt. Finally, the sound absorption properties of the multi-layer structural composite materials were studied by changing flax felt thickness, air cavity depth, slit rate, and thickness of micro-slit panel. As the flax felt thickness varied from 0 to 10 mm in 5 mm increments, the peak of sound absorption coefficient shifted to low frequency. The sound absorption coefficient in the low frequency was improved with the air cavity depth varied from 0 to 10 mm in 5 mm increments. With the slit rate increased from 3% to 7% in 2% increments, the peak of sound absorption coefficient shifted to high frequency. With the thickness of micro-slit panel increased from 2 to 6 mm in 2 mm increments, the sound absorption bandwidth was broaden, and the peak of sound absorption coefficient was increased and shifted to low frequency. Results showed that the highest sound absorption coefficient of the multi-layer structural composite materials was about 1 under the optimal process conditions.

Studies of the Influence of Graphite on the Physical Mechanical and Thermal Properties of Polyurethane Foams for Construction Applications

2021 ◽  
Vol 887 ◽  
pp. 399-405
Author(s):  
L.N. Shafigullin ◽  
N.V. Romanova ◽  
G.R. Shafigullina
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Polyurethane Foams ◽  
Onset Temperature ◽  
Sound Absorption Coefficient ◽  
Expandable Graphite ◽  
Mechanical And Thermal Properties ◽  
Pu Foam

The paper shows the applicability of expandable graphite METOPAC EG 350-50 (80) in a rigid PU foam system as a substance that reduces the flammability (flame retardant) and improves the usability. The studies of the physical mechanical and thermal properties of PU foam with a higher graphite content revealed a higher normal sound absorption coefficient; insignificant influence on the thermal conductivity; a higher decomposition onset temperature; more difficult ignition. PU foam sample with a ratio of 15 graphite weight fractions to 100 polyol weight fractions has the highest physical mechanical and thermal properties, and, as compared to the starting PU foam, it features an increase in normal sound absorption coefficient by an average of 3 times; a decrease in the thermal conductivity by 8 %; an increase in the decomposition onset temperature by 6.7 °С. Therefore, the modification of PU foam with expandable graphite makes it possible not only to develop hardly combustible polyurethanes but also to improve its physical mechanical and thermal properties.

The effect of physical parameters on sound absorption properties of natural fiber mixed nonwoven composites

2012 ◽  
Vol 82 (20) ◽  
pp. 2043-2053 ◽  
Author(s):  
Merve Küçük ◽  
Yasemin Korkmaz
Keyword(s):  
Absorption Coefficient ◽  
High Frequency ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Unit Area ◽  
Air Permeability ◽  
Physical Parameters ◽  
Fiber Types ◽  
Absorption Properties ◽  
Nonwoven Fabrics

In this study, the effects of physical parameters on sound absorption properties of nonwoven fabrics were investigated. Eight different nonwoven composites including different fiber types mixed with different ratios were tested. Along with sound absorption properties, thickness, weight per area, and air permeability parameters of the samples were measured. The increase in thickness and the decrease in air permeability results in an increase in sound absorption properties of the material. The samples including 70% cotton and 30% polyester resulted in the best sound absorption coefficient in the mid-to-high frequency ranges. The increase in the amount of fiber per unit area resulted in an increase in sound absorption of the material. Addition of acrylic and polypropylene into a cotton and polyester fiber mixture increased the sound absorption properties of the composite in the low and mid-frequency ranges also.

Sound Absorption Properties of Fiber and Porous Materials

2005 ◽  
Vol 475-479 ◽  
pp. 2687-2690 ◽  
Author(s):  
Bo Young Hur ◽  
Bu Keoun Park ◽  
Dong-In Ha ◽  
Yong Su Um
Keyword(s):  
Absorption Coefficient ◽  
Porous Materials ◽  
Sound Absorption ◽  
Absorption Rate ◽  
Metal Foam ◽  
Acoustic Property ◽  
Glass Wool ◽  
Sound Absorption Coefficient ◽  
Absorption Properties ◽  
Reduction Coefficient

The porous materials, such as glass wool or foam, are generally used to attenuate noise. The most fundamental acoustic property of these porous materials is their sound absorption coefficient. The purpose of this paper is sintered fiber and porous materials sound absorption properties investigated. Sound absorption properties of sintered Al fiber has over 0.7 of sound absorption coefficient with 800-2000Hz frequency for 0.6 relative density and 10mm thickness. NRC (noise reduction coefficient) is 0.73. Metal foam have good sound absorption rate at 2000 ~ 4000Hz.

The Effects of Thermal Consolidation Methods on PET Nonwoven Composites for Thermal Insulation Use

2008 ◽  
Vol 55-57 ◽  
pp. 405-408 ◽  
Author(s):  
Ching Wen Lou ◽  
Ching Wen Lin ◽  
Chia Chang Lin ◽  
S.J. Li ◽  
I.J. Tsai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Consumption ◽  
Thermal Insulation ◽  
Aluminum Foil ◽  
Nonwoven Fabric ◽  
Nonwoven Fabrics ◽  
Available Energy ◽  
Needle Punching ◽  
Thermal Consolidation ◽  
Pet Fibers

As available energy sources have grown increasingly scarce, people have started paying attention to their energy consumption. Although many methods for power generation are being actively investigated, efficient methods for solving energy problems must be based on reducing energy consumption. Thermal insulation can decrease heat energy loss and conserve energy waste, especially in the construction, transportation and industrial fields. In this study, polyester (PET) hollow fibers were blended with various ratios of low-melting-point PET fibers (10%, 20%, 30%, 40% and 50%). The fibers were blended using opening, carding, laying and needle punching (150 needles/cm2, 225 needles/cm2 and 300 needles/cm2) to prepare PET nonwoven fabrics. The PET nonwoven fabrics were thermally plate pressed (TPP) and air-through bonding (ATB). Thermal conductivity, physical properties and air permeability were investigated to identify the influence of manufacturing parameters on the PET nonwoven fabrics. The experimental results show that needle punching density, TPP and ATB would influence the thermal conductivity of PET nonwoven fabric, because the structure of PET nonwoven fabric was changed. The optimal parameters of PET nonwoven fabric clipped with an aluminum foil was used to evaluate the influence of aluminum foil on thermal conductivity. The PET nonwoven composite in this study can be used in industrial thermal insulation applications.

Fabrication and Sound Absorption Properties of Porous Fe0.2(Co20Ni80)0.8 Alloy Microfibers

2012 ◽  
Vol 538-541 ◽  
pp. 2220-2223
Author(s):  
Xiang Qian Shen ◽  
Hong Bo Liu ◽  
Qing Rong Liang ◽  
Xin Chun Yang
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Transformation Process ◽  
Sound Absorption Coefficient ◽  
Wave Tube ◽  
Absorption Properties ◽  
Thick Sample ◽  
Noise Absorption ◽  
Reduction Coefficient ◽  
Standing Wave Tube

The porous nanocrystalline Fe0.2(Co20Ni80)0.8 alloy microfibers with diameters of 2-4 μm have been prepared by the citrate-gel and phase transformation process. The sound absorption coefficient for microfibers samples is measured by the standing wave tube method and it is is over 0.8 for the 15 mm thick sample at the frequency range of 2300-6000 Hz, which is extended to 600-6300 Hz for the 40 mm thick sample. The band width with the sound absorption coefficient above 0.6 is wider than 4300 Hz for the 15 mm thick sample and 5800 Hz for the 40 mm thick sample. For the 40 mm thick sample, the maximum absorption coefficient, noise absorption coefficient, noise reduction coefficient and half-width of the absorption peak are 0.99, 0.59, 0.64 and 5828 Hz, respectively. These microfibers are promising advanced acoustic absorbers.

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