Correlation between Frequency and Sound Absorption Coefficient of Polymer Reinforced Natural Fibre

2015 ◽  
Vol 1112 ◽  
pp. 329-332 ◽  
Author(s):  
Mohammad Farid ◽  
Hosta Ardhyananta ◽  
Vania Mitha Pratiwi ◽  
Sri Pingit Wulandari
Keyword(s):  
Aspect Ratio ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Average Diameter ◽  
Optical Microscope ◽  
Bamboo Fiber ◽  
Sound Absorption Coefficient ◽  
Ramie Fiber ◽  
Medium Frequency

Aspect ratio which is the ratio between the length and diameter of the fiber affects the sound absorption performance of the polymer reinforced natural fiber (ramie or bamboo fiber). The aim of this study is to choose the specific frequency –which is important for industrial application- to obtain an optimal sound absorption coefficient (α) by designing a certain aspect ratio.The acoustic was measured using impedance tube of The ASTM E- 1050=98 standard. Fiber length was 10 mm, while the diameter of the fiber was measured by using a digital optical microscope measurement with an average diameter of 110.4 microns. The morphology of the material was observed by using scanning electron microscope (SEM). Fourier Transform Infrared (FTIR) spectroscopy was used to identify the presence of certain functional groups in a molecule. The results indicated that the average of the sound absorption coefficient of the polymer reinforced ramie fiber reached 0,836 at low frequency of 125 Hz and 0,537 at medium frequency of 1000 Hz, and aspect ratio of 90, while the sound absorption coefficient of the polyester material reinforced bamboo fiber reached 0.973 at medium frequency of 1000 Hz.

scholarly journals Acoustic, Mechanical and Thermal Properties of Green Composites Reinforced with Natural Fibers Waste

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 654 ◽  
Author(s):  
Tufail Hassan ◽  
Hafsa Jamshaid ◽  
Rajesh Mishra ◽  
Muhammad Qamar Khan ◽  
Michal Petru ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Coefficient Of Thermal Expansion ◽  
The Other ◽  
Fiber Reinforced Composites ◽  
Sound Absorption Coefficient ◽  
Mechanical And Thermal Properties ◽  
Reinforced Composites ◽  
Fiber Reinforced

The use of acoustic panels is one of the most important methods for sound insulation in buildings. Moreover, it has become increasingly important to use green/natural origin materials in this area to reduce environmental impact. This study focuses on the investigation of acoustic, mechanical and thermal properties of natural fiber waste reinforced green epoxy composites. Three different types of fiber wastes were used, e.g., cotton, coconut and sugarcane with epoxy as the resin. Different fiber volume fractions, i.e., 10%, 15% and 20% for each fiber were used with a composite thickness of 3 mm. The sound absorption coefficient, impact strength, flexural strength, thermal conductivity, diffusivity, coefficient of thermal expansion and thermogravimetric properties of all samples were investigated. It has been found that by increasing the fiber content, the sound absorption coefficient also increases. The coconut fiber-based composites show a higher sound absorption coefficient than in the other fiber-reinforced composites. The impact and flexural strength of the cotton fiber-reinforced composite samples are higher than in other samples. The coefficient of thermal expansion of the cotton fiber-based composite is also higher than the other composites. Thermogravimetric analysis revealed that all the natural fiber-reinforced composites can sustain till 300 °C with a minor weight loss. The natural fiber-based composites can be used in building interiors, automotive body parts and household furniture. Such composite development is an ecofriendly approach to the acoustic world.

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.

Development of Sound Absorbent Material Based on Waste and Bamboo Fiber

2015 ◽  
Vol 1112 ◽  
pp. 367-370 ◽  
Author(s):  
Arjuni B. Pantjawati ◽  
Enjang A. Juanda ◽  
Budi Mulyanti ◽  
Azis Mujtahid ◽  
Aldi Wiryadi
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Bamboo Fiber ◽  
Sound Absorption Coefficient ◽  
Drying Process ◽  
Absorbent Material ◽  
Processed Material ◽  
Acoustic Quality ◽  
Inorganic Waste

Sound absorbent material is used to improve acoustic quality of room as it can damp noise level and reduce echo. As the manufacturing costs are quite expensive, nowadays, utilization of sound absorbent material is still limited to commercial needs, such as karaoke room, movie theater and music studio. Utilizing waste into sound absorbent materials can provide multiple benefits as it can reduce production cost and landfill waste as well. This research was conducted experimentally with parameter measured was sound absorption coefficient. An organic waste such as vegetable waste and an inorganic waste such as plastic, paper, and fabrics waste were processed through crushing and drying process. The processed material was mixed with bamboo fiber and an organic Nano silica (rice husk). The Compound was used as filler and was mixed with polyvinyl acetate (PVAc) as a matrix. From this research, it was concluded that composite material from waste with bamboo fiber could qualify ISO 11654, 1997 standard as a sound absorbent material E class category with weighted sound absorption coefficient value, αw= 0,25(M). This material has a good sound absorption quality in frequency range 500-1250 Hz with highest absorption α = 0.82 at 800 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).

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%.

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