Experimental assessment of the sound absorption coefficient of three natural fibers

2019 ◽  
Vol 146 (4) ◽  
pp. 2868-2868
Author(s):  
Ana Carolina M. Mansur ◽  
Alisson Zanetti ◽  
Nilson Barbieri ◽  
Key F. Lima
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Natural Fibers ◽  
Sound Absorption Coefficient ◽  
Experimental Assessment

scholarly journals Experimental Study on the Sound Absorption Properties of Finger Millet Straw, Darbha, and Ripe Bulrush Fibers

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
K. M. Rakesh ◽  
Ramachandracharya Srinidhi ◽  
S. Gokulkumar ◽  
K. S. Nithin ◽  
S. Madhavarao ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Finger Millet ◽  
Natural Fiber ◽  
Fiber Type ◽  
Natural Fibers ◽  
Noise Pollution ◽  
Sound Absorption Coefficient ◽  
Human Beings ◽  
Fiber Arrangement

Nowadays, emerging noise pollution by external factors causes harmful diseases in human beings. The development of a bio-based filler or panel will help to eliminate some unwanted noise in working places and living rooms. This work aimed to develop an ecowaste fiber (leftover after harvesting)-based sound absorber and analyze its capabilities for sound absorption. The ecowaste fibers are collected by the gleaning process, i.e., the process of collecting leftovers from fields. The sound absorption capabilities of three natural fibers extracted from Eleusine coracana (Finger millet) straw, Desmostachya bipinnata (Darbha), and Typha domingensis (Ripe bulrush) plants are investigated in this study, both individually and in hybrid combinations. The sound absorption property mainly depends on factors such as porosity, flow resistivity, thickness, density, and tortuosity. Fiber length and fiber type play a significant role when fibers are arranged individually or in hybrid combinations. The stacking effect on the sound absorption coefficient of hybridized fiber arrangement was experimentally analyzed. The sound absorption coefficient (α) was found to be lower in the range of 1000 Hz–2500 Hz for all the combinations. As a homogenous fiber arrangement, the darbha fiber exhibited the better NRC (noise reduction coefficient) of 0.86 for 50 mm thickness among three different fibers and as a hybrid composition, ripe bulrush and darbha fibers exhibited NRC of 0.90 which is more capable of absorbing sound in the critical frequency range of 500 to 2000 Hz. These types of natural fiber fillers are highly capable of better sound absorbing and used in the applications such as classrooms, sound recording rooms, and theatres.

Comparative Study of Sound Absorption Coefficients of Coir/Kenaf/Sugarcane Bagasse Fiber Reinforced Epoxy Composites

2017 ◽  
Vol 730 ◽  
pp. 48-53 ◽  
Author(s):  
Elammaran Jayamani ◽  
Soon Kok Heng ◽  
Muhammad Khusairy bin Bakri ◽  
Sinin Hamdan
Keyword(s):  
Absorption Coefficient ◽  
Sugarcane Bagasse ◽  
Sound Absorption ◽  
Transfer Functions ◽  
Natural Fibers ◽  
Epoxy Composites ◽  
Sound Absorption Coefficient ◽  
Coconut Coir ◽  
Impedance Tube Method ◽  
Bagasse Fiber

This research focuses on the sound absorption coefficient of three different natural fibers reinforced epoxy composites. The natural fibers used are coconut coir, kenaf, and sugarcane bagasse. All of these fibers were mixed with epoxy resin and hardener with a ratio of 4:1. The mixtures were then poured into a circular mold and compressed by using compression molding technique. It was left for curing for 24 hours at standard room temperature. The results were obtained using the two-microphone transfer functions impedance tube method according to ASTM E1050-12. It is found that as the fiber loading increased, the sound absorption coefficient of the composites increased. 20wt% Coconut coir epoxy composites and 20wt% kenaf fiber epoxy composites have the highest sound absorption coefficient with almost similar sound absorption of 0.078 at 5000Hz. While, 20wt% sugarcane bagasse epoxy composites have sound absorption of 0.075 at 5000Hz.

Evaluation and comparison the properties of acoustic boards made of date palm fiber

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7702-7715
Author(s):  
Mehdi Alishiri ◽  
Amir Hooman Hemmasi ◽  
Habibollah Khademi Eslam ◽  
Sedigheh Basirjafari ◽  
Mohammad Talaeipour
Keyword(s):  
Absorption Coefficient ◽  
Sodium Silicate ◽  
Sound Absorption ◽  
Date Palm ◽  
Agricultural Waste ◽  
Natural Fibers ◽  
Control Sample ◽  
Sound Absorption Coefficient ◽  
Synthetic Fibers ◽  
Particle Length

Applying acoustic panels made of natural fibers, due to their high biodegradable characteristics, light weight, low density, cheap price and non-toxicity, are proper alternatives to acoustic absorbers made of synthetic fibers. Considering their stance and vast applicability in industry, the possibility of producing them of natural palm fibers with sodium silicate adhesive of 10 and 20% in two 16 and 32 mm thicknesses, 350 and 450 kg/m3 densities, 50 and 100 mm particles length (strands), as variable factors in 16 types of matched panels with 3 repetitions is proposed in this article. The palm-trunk discs constituted the control sample. The effect of variables on sound absorption coefficient was assessed. The effect of variable thickness and adhesive percentage on all frequencies was significant and the effect of density variable on all frequencies except 250 and 2000 Hz was also significant. The effect of particle length was significant except at the 500 Hz frequency. The effects of all variables on porosity were significant. The results of this study suggest that by applying date palm-trunk (an agricultural waste) combined with sodium silicate adhesive, industrial environment-friendly panels can be produced with proper sound absorption coefficient in the field of acoustics. This 32-mm-thick panel was composed of 80% date palm-trunk particles of 50 mm length, 450 kg/m3 density, and 20% sodium silicate adhesive.

Study on the Sound Absorption Properties of Several Kinds of Fibers

2011 ◽  
Vol 332-334 ◽  
pp. 959-962
Author(s):  
Yong Hua Ren ◽  
Xiao Ning Sun ◽  
Hong Song
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Cavity Length ◽  
Natural Fibers ◽  
Influence Factors ◽  
Sound Absorption Coefficient ◽  
Cotton Wool ◽  
Absorption Properties ◽  
Material Thickness ◽  
Noise Frequency

In this paper, four kinds of natural fibers (cotton, wool, silk and ramie) are studied. Three experimental programs are designed, and influence factors of sound absorption properties of porous sound absorption material are discussed. With the change of material thickness and cavity length, the variation of sound absorption coefficient is obtained in different noise frequency.

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).

scholarly journals Air permeability and sound absorption coefficient changes from ultrasonic treatment in a cross section of Malas (Homalium foetidum)

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Chun-Won Kang ◽  
Eun-Suk Jang ◽  
Nam-Ho Lee ◽  
Sang-Sik Jang ◽  
Min Lee
Keyword(s):  
Absorption Coefficient ◽  
Ultrasonic Treatment ◽  
Sound Absorption ◽  
Gas Permeability ◽  
Treated Wood ◽  
Untreated Wood ◽  
Sound Absorption Coefficient ◽  
Permeability Constant ◽  
Average Value ◽  
Permeability Increase

AbstractWe investigated the effect of ultrasonic treatment on Malas (Homalium foetidum) gas permeability and sound absorption coefficient using the transfer function method. Results showed a longitudinal average Darcy permeability constant of 2.02 (standard deviation SD 0.72) for untreated wood and 6.15 (SD 3.07) for ultrasound-treated wood, a permeability increase of 3.04 times. We also determined the average sound absorption coefficients in the range of 50 to 6.4 kHz and NRC (noise reduction coefficient: average value of sound absorption coefficient value at 250, 500, 1000, and 2000 Hz) of untreated Malas. Those values were 0.23 (SD 0.02) and 0.13 (SD 0.01), respectively, while those of ultrasonic-treated Malas were 0.28 (SD 0.02) and 0.14 (SD 0.02), a 19.74% increase in average sound absorption coefficient.

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

2018 ◽  
Vol 89 (16) ◽  
pp. 3342-3361 ◽  
Author(s):  
Tao Yang ◽  
Ferina Saati ◽  
Kirill V Horoshenkov ◽  
Xiaoman Xiong ◽  
Kai Yang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Absorption Coefficient ◽  
Empirical Model ◽  
Surface Impedance ◽  
Sound Absorption ◽  
Low Frequency ◽  
Accurate Method ◽  
Small Error ◽  
Sound Absorption Coefficient ◽  
Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

Sign in / Sign up

Export Citation Format

Share Document