Investigation of sound transmission loss of natural fiber/rubber crumbs composite panels

2021 ◽  
pp. 152808372110395
Author(s):  
Magdi El Messiry ◽  
Yasmin Ayman
Keyword(s):  
Natural Fiber ◽  
Transmission Loss ◽  
Natural Fibers ◽  
Sound Transmission ◽  
Nonwoven Fabric ◽  
Acoustic Properties ◽  
Cotton Wool ◽  
Sound Transmission Loss ◽  
High Frequencies ◽  
The World

Natural fibers and their waste are widely used all over the world, and their production has been increasing continuously. But, the rubber crumbs from used tire disposal are nonbiodegradable and present significant problems about their end-of-life given a critical environmental impact. These problems require recycling policies to provide the collection and recycling of used clothing, textile wastes, and rubber crumbs. In this work, the acoustic properties of insulator panels from the combination of textile fibers and rubber crumbs material were analyzed. Insulator panels demonstrated a good sound transmission loss (STL) characteristic, especially at high frequencies. The STL of the manufactured panels from a combination of fiber (cotton, wool, and Kapok) and rubber crumbs was investigated at the different sound frequencies. Results indicated that the fiber/rubber crumbs panel had a significant STL profile of 47 dB, 40 dB, and 35 dB, for Kapok, wool, and cotton, respectively. The addition of polylactic acid meltblown nonwoven fabric on the surface of the rubber crumbs side considerably increases the STL by 20%.

scholarly journals High sound absorption of polyester composites / fiber hemp / nanocellulose for automotive interior materials

2020 ◽  
Vol 2 (2) ◽  
pp. 170-174
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Sound Absorption ◽  
Natural Fiber ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Hemp Fiber ◽  
The Matrix ◽  
Polyester Composite

Human health and environmental comfort are disturbed by the presence of noise, especially in cars, so that effective sound-absorbing materials are currently being developed. To answer the problem of noise in car interiors, polyester composite materials with local hemp fiber and nanocellulose reinforcement were developed. Natural fiber is biodegradable and renewable, and acts as an alternative to the use of synthetic fibers. The method used for the composite material manufacturing process was the casting method. The matrix of the composite material was polyester, while the reinforcement was a combination of local hemp fiber and nanocellulose fiber. Alkalization and non-alkalization processes have been carried out on hemp fiber. The composition of nanocellulose was 0%, 1%, and 3%. The characterization applied in this research were SEM test, FTIR test, sound transmission loss test, and density test. Optimal results were obtained on hemp fiber reinforced polyester composite materials without alkalization and without nanocellulose. Sound transmission loss (STL) was 61.91 dB up to 68.52 dB for the frequency range of 630 Hz to 125 Hz. The standard noise limit on 8-passenger passenger's four-wheeled vehicles is 77-80 dB. Based on the results obtained, the sound absorption is good. The density of this composite material was obtained at 0.989 gram/cm3. This composite material has the potential for developing dashboard material.

Incorporation of Nanofiber Layers in Nonwoven Materials for Improving Their Acoustic Properties

2013 ◽  
Vol 8 (4) ◽  
pp. 155892501300800 ◽  
Author(s):  
Amir Rabbi ◽  
Hossein Bahrambeygi ◽  
Ahmad Mousavi Shoushtari ◽  
Komeil Nasouri
Keyword(s):  
Sound Absorption ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Wide Band ◽  
Acoustic Properties ◽  
Sound Insulation ◽  
Sound Transmission Loss ◽  
Factors Affecting ◽  
Nonwoven Materials ◽  
Field Noise

Due to numerous developments in most industries and the increase in the usage of massive and powerful machines in every field, noise has become an unavoidable part of mechanized life and has brought about serious health hazards. The main aim of this work was to investigate the usability of polyurethane and polyacrylonitrile nanofibers for improving sound insulation properties over a wide band of frequencies and reducing weight and thickness of conventional polyester and wool nonwovens. The effect of the number of nanofiber layers and associated surface densities on acoustic properties was investigated. Sound transmission loss and sound absorption analysis using the impedance tube method were carried out as the main factors affecting acoustic behavior of samples. The results show that incorporation of nanofiber layers in nonwoven materials can improve both sound absorption and sound transmission loss simultaneously, especially in mid and lower frequencies, which are difficult to detect by conventional materials.

scholarly journals Analyzing and evaluation of effective parameters on sound transmission loss of the triple-layered acoustic panels with sound-absorbing middle layer

2015 ◽  
Vol 4 (2) ◽  
pp. 250
Author(s):  
Nader Mohammadi
Keyword(s):  
Boundary Condition ◽  
Porous Material ◽  
Elastic Layer ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Air Gap ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Static Young’S Modulus ◽  
Wide Range

In this research, a triple-layered acoustic panel with sound-absorbing intermediate layer materials is modeled analytically in order to calculate the sound transmission loss in the normal incidence field. This information provides an appropriate platform for optimum noise control. In this paper, porous material is used as an absorbent layer between two elastic panels. In modeling these triple-layered panels, theory of wave propagation in porous materials is used and bounded boundary condition of the first elastic layer and unbounded boundary condition of the second elastic layer is applied. To validate the model, the results of this model are compared with the results of the Bolton. Comparison of results revealed very good compatibility. Here, the effect of the length of the air gap between the elastic layers, density and the material of the elastic plate, the thickness and vibro-acoustic properties of the intermediate porous material on the values of transmission loss is investigated.In a wide range of frequencies, increasing air gap, density of elastic panels and porous layer thickness, increase the transmission loss up to 10 dB. At frequencies above 10 kHz, a reduction in porosity, static Young's modulus, the loss coefficient, increasing bulk density of the solid phase, the factor of geometrical structure and viscosity of porous material, increase the sound transmission loss up to 15 dB.

scholarly journals Utilisation of High Energy Propellant Waste in Manufacturing of Fired Clay Bricks to Enhance the Acoustic Properties

2021 ◽  
Vol 71 (5) ◽  
pp. 639-646
Author(s):  
P.K. Mehta ◽  
A. Kumaraswamy ◽  
V.K. Saraswat ◽  
B. Praveen Kumar
Keyword(s):  
Waste Management ◽  
Transmission Loss ◽  
Experimental Studies ◽  
Sound Transmission ◽  
High Energy ◽  
Environmental Hazards ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Clay Bricks ◽  
Directional Orientation

The disposal and waste management of solid high energy propellant (HEP) is a considerate conservational problem. HEP waste is currently disposed in open or confined burning which may cause environmental hazards. In this paper, we examined and discussed results on recycling of HEP waste into fired clay bricks baked in different orientation. HEP modified bricks with 1.5%, 3% and 5 wt. % HEP waste content were manufactured and tested, and then compared against virgin clay bricks without HEP content. The effect of directional orientation of bricks baked with varying HEP content on acoustic properties were experimented and discussed. The sound transmission loss decreases with increase in HEP waste due to formation of independently closed directional pores. The transmission loss of horizontally baked during firing of bricks is nearly 5dB lower than vertically baked bricks. Results of the experimental studies indicate that HEP waste can be utilised in fired clay bricks and different orientation baking further enhances the acoustic properties.

scholarly journals On the Determination of Acoustic Properties of Membrane Type Structural Skin Elements by Means of Surface Displacements

2021 ◽  
Vol 11 (21) ◽  
pp. 10357
Author(s):  
Daniel Urbán ◽  
N. B. Roozen ◽  
Vojtech Jandák ◽  
Marek Brothánek ◽  
Ondřej Jiříček
Keyword(s):  
Plane Wave ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Transmission Loss ◽  
Laser Doppler Vibrometer ◽  
Sound Transmission ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Membrane Type

The article focuses on the determination of the acoustic properties (sound transmission loss, sound absorption and transmission coefficient under acoustic plane wave excitation) of membrane-type of specimens by means of a combination of incident plane wave sound pressure and membrane surface displacement information, measuring the sound pressure with a microphone and the membrane displacement by means of a laser Doppler vibrometer. An overview of known measurement methods and the theoretical background of the proposed so-called mobility-based method (MM) is presented. The proposed method was compared with the conventional methods for sound transmission loss and absorption measurement in the impedance tube, both numerically and experimentally. Finite element model (FEM) simulation results of two single layer membrane samples of different shape configurations were compared, amongst which six different variations of the backing wall termination. Four different approaches to determine the sound transmission loss and two methods to determine sound absorption properties of the membranes were compared. Subsequently, the proposed method was tested in a laboratory environment. The proposed MM method can be possibly used to measure the vibro-acoustic properties of building parts in situ.

Experimental study to measure the sound transmission loss of natural fibers at tonal excitations

2020 ◽  
Vol 28 ◽  
pp. 1554-1559 ◽  
Author(s):  
Ankush Kesharwani ◽  
Raman Bedi ◽  
Ashok Kumar Bagha ◽  
Shashi Bahl
Keyword(s):  
Experimental Study ◽  
Transmission Loss ◽  
Natural Fibers ◽  
Sound Transmission ◽  
Sound Transmission Loss

scholarly journals Design, Manufacturing, and Acoustical Analysis of a Helmholtz Resonator-Based Metamaterial Plate

Acoustics ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 630-641
Author(s):  
Sourabh Dogra ◽  
Arpan Gupta
Keyword(s):  
Transmission Loss ◽  
Sound Transmission ◽  
Helmholtz Resonator ◽  
Acoustic Properties ◽  
Sound Transmission Loss ◽  
Sound Waves ◽  
Acoustic Metamaterials ◽  
Additional Advantage ◽  
Helmholtz Resonators ◽  
High Sound

Acoustic metamaterials are materials artificially engineered to control sound waves, which is not possible with conventional materials. We have proposed a design of an acoustic metamaterial plate with inbuilt Helmholtz resonators. The plate is made of Polylactic acid (PLA) which is fabricated using an additive manufacturing technique. It consists of Helmholtz resonator-shaped cavities of different sizes. In this paper, we have analyzed the acoustic properties of the Helmholtz resonators-based metamaterial plate experimentally as well as numerically. The experimental results are in good agreement with the numerical results. These types of 3D-printed metamaterial plates can find their application where high sound transmission loss is required to create a quieter ambience. There is an additional advantage of being lightweight because of the Helmholtz resonator-shaped cavities built inside the plate. Thus, these types of metamaterial plates can find their application in the design sector requiring lighter materials with high sound transmission loss.

Investigation of the acoustic properties of needle punched nonwoven produced of blend with sustainable fibers

2018 ◽  
Vol 30 (3) ◽  
pp. 444-458 ◽  
Author(s):  
Shariful Islam ◽  
Shaikh Md. Mominul Alam
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Transmission Loss ◽  
Natural Fibers ◽  
Sound Transmission ◽  
Textile Composites ◽  
Acoustic Properties ◽  
Textile Composite ◽  
Content Type ◽  
Hemp Fibers

Purpose The purpose of this paper is to investigate the acoustic properties of needle-punched nonwovens produced of bamboo, banana and hemp fibers blended with polyester (PET) and polypropylene (PP) as they are supportive enough to minimize sound transmission inside the automobiles. Design/methodology/approach Textile materials like bamboo, banana and hemp blended with PET and PP in the ratio of 35:35:30 were applied to make the web. The needle-punching technique was applied to each web for three times to form a full nonwoven textile composite. The concept of PET/PP blend with natural fibers was to enhance the consistency and thermoform propensity of the composites. When nonwoven textile composites were placed in between a sound source and a receiver, they absorbed annoying sound by dissolving sound wave energy. Sound absorption coefficient was measured by the impedance tube method as per ASTM C384 Standard. Bamboo/PET/PP composite showed the highest absorption coefficient in most of the frequencies. Findings Physical and comfort properties were tested for the composites and it was noticed that bamboo/PET/PP composites with its compressed structure showed a better stiffness value, lesser thermal conductivity, lesser air permeability, better absorption coefficient and highest sound transmission loss compared to other two composites. At 840 Hz, the absorption coefficient of bamboo/PET/PP remained in satisfactory level but it was inferior by 20 percent in banana/PET/PP. Conversely at more frequencies like 1,680 Hz, there was a decrease from the target level in all the nonwovens composites, which could be enhanced by raising the thickness of the nonwovens, and all these properties of bamboo/PET/PP were considered appropriate for controlling noise inside the vehicles. Practical implications This research will provide facilities to decrease noise inside the vehicles. It will improve the apparent value of the automobiles to the traveler and also provide a sensible goodwill to the manufacturer. Originality/value This research will open several ways for the development of different nonwoven composites, particularly for the sound absorption and will open possible ways for the scholars to further study in this field.

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