Development of Semi-Active Panel Design for Sound Absorption

2014 ◽  
Vol 663 ◽  
pp. 421-425
Author(s):  
N.S.S. Selamat ◽  
Mohd Faizal Mat Tahir ◽  
Rozli Zulkifli ◽  
Mohd Jailani Mohd Nor ◽  
Mohd Anas Mohd Sabri ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Coir Fiber ◽  
Perforated Plates ◽  
Simulation Results ◽  
Perforation Plates ◽  
Impedance Tube Method ◽  
Air Cavities ◽  
Panel Design

Various noise-absorbing materials and apparatus were developed not only for industry purposes but also for increased personal convenience through the absorption of unwanted sound. Absorbing products are typically passive mediums, whereas active-control absorption is expensive and complicated to install. Thus, in this study, a semi-active panel design for the sound absorber is developed to ensure operation at a required absorption level for a particular environment and to allow manual control. This study focused on producing an optimum design from several blueprints by using the simulation program, WinFlag. Simulation results are validated by using the impedance tube method. The samples used are perforated plates with open areas of 5%, 7.5%, 10%, 12.5%, ​​and 15%. The second layer is a 35-mm thick coconut coir fiber as the main absorbing material. The third layer is air cavity. Simulation results indicate that the panel with perforation plates with 15% open areas gained the highest peak of sound absorption coefficient (0.851) at 5000 Hz. By using 30 mm thick air cavities, the highest peak is 0.963 at 3129 Hz. Experimental results indicate that the highest peak of sound absorption coefficient is 0.847 for the 15% open area of perforated plates, whereas the highest peak is 0.934 when 30 mm thick air cavities are used. The same pattern in the overall results denotes that the experiment result agrees with that of the simulation

Sound Absorption Characteristic of Glass and Plastic Bottles: Considerations of Their Dependences on Material Properties

2018 ◽  
Author(s):  
Teruo Iwase ◽  
Satoshi Sugie ◽  
Hiroyasu Kurono ◽  
Masayuki Abe ◽  
Yasuaki Okada ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Resonance Frequency ◽  
Sound Absorption ◽  
Helmholtz Resonator ◽  
Green Building ◽  
Sound Absorption Coefficient ◽  
Absorption Characteristic ◽  
Impedance Change ◽  
Perforated Plates ◽  
Section Area

Great number of bottles made by glass, plastic and metal are used to store beverages, liquid ingredients as water, milk, vinegar and also liqueur. Empty bottles after usage are collected for recycling use and resources. Many of them have narrow open mouth and look like typical shape in kinds of Helmholtz resonator. Authors thought that their reuse for functional building parts with sound absorption would be very valuable from points of view of green building and environmental policies, and authors then measured each resonance frequency and sound absorption coefficient of representative, including light-soft-plastic, bottles, with net capacity from 7 to 2000 ml, by setting on the edge of sound tube with diameter of 100 mm. Sound resonances with sound absorption coefficient of 0.3–1.0 at frequencies from 100 to 1000 Hz clearly depending on the capacity could be confirmed. It was also found that measured result was well matched to the numerical calculation based on acoustic impedance change at each section area gradually changed in bottle. It is thought that combination use of recycled bottles with independent resonance frequency is more effective than use of new uniform perforated plates for wide space where we need additional sound absorption in certain frequency range.

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.

Acoustic Absorption Performance Research of Coir Density Board

2012 ◽  
Vol 549 ◽  
pp. 589-592
Author(s):  
Jia Yao ◽  
Li Li Ma ◽  
Lu Wei ◽  
Li Wei Jiang ◽  
Ya Qin Li
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Optimization Design ◽  
Morphological Characteristics ◽  
Wave Impedance ◽  
Sound Absorption Coefficient ◽  
Coir Fiber ◽  
Tropical Fruit ◽  
Practical Applications ◽  
Absorption Performance

Coir fiber is one of the tropical fruit fibers, the effective use of coir is not comprehensive now and the phenomenon of resources waste still exists. Full study of the advantage characteristics of coir has important significance for the expansion of the application field of coir resources. This article determines the light porous characteristics of coir from the micro-morphological characteristics. Through the prediction model research of the sound absorption coefficient of the porous fiber materials, the optimization density and the optimization thickness ranges can be got for the coir density board, so as to guide the optimization design of the sound absorption performance of coir density board. The changing rule of the sound absorption coefficient of the coir density board has been got by adopting the wave impedance tube method and the sound absorption coefficients by adding 5cm air gap has also been researched. The results of the experiments confirm that coir density board can be used as a secondary noise absorption material; the practical applications of coir density board are as the lightweight wall, the car interior trim or seat filling materials and the shipping cabins materials, to reduce the corresponding environment noise.

scholarly journals Fiber Weight Fraction Effect to Acoustic Properties of RHDPE Cantula Composite

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
Muhammad Taufik Burhany Hendrowarsito ◽  
Wijang Wisnu Raharjo ◽  
Dwi Aries Himawanto
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Density Measurement ◽  
Weight Ratio ◽  
Weight Fraction ◽  
Acoustic Properties ◽  
Sound Absorption Coefficient ◽  
Hot Press ◽  
Coefficient Increase ◽  
Impedance Tube Method

In this study, composites made from recycled HDPE and Cantula fiber have been done and the absorption coefficient have been measured. Composites rHDPE-Cantula were made using hot press for approximately 60 minutes with 170oC temperature while pressure exerted by 50 bar. In this study the weight ratio of Cantula fiber was varied 40%, 50%, 60%, and 70%. Impedance Tube Method was used to measure the sound absorption coefficient in accordance with ASTM E 1050. An increase weight ratio wasn’t influence the sound absorption coefficient significantly, but the optimum sound absorption coefficient shifted to the higher frequencies from 80-200 Hz. An increase weight ratio showed better sound absorption coefficient from 500-1600 Hz, but the result from 60% weight ratio showed low sound absorption coefficient that may caused by it high density leading to the reduction of porosity. This result was supported by density measurement in accordance with ASTM D 792, which the result showed that the sound absorption coefficient increase with decreasing of the density.

scholarly journals STUDY AND ANALYSIS ON SOUND ABSORBING AND NOISE REDUCING PERFORMANCE OF TIMBER CONSTRUCTION WALL BASED ON ACOUSTIC SPIRAL MATASURFACE

Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 341-352
Author(s):  
Haiyan Fu ◽  
Xinyue Zhao ◽  
Patrick Adjei ◽  
Zheng Wang ◽  
Xiaoli Wu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Impedance Tube ◽  
Frequency Sound ◽  
Timber Construction ◽  
Absorption Performance ◽  
Impedance Tube Method ◽  
Structural Layer

Based on acoustic spiral metasurface, a spiral structural layer was designed to apply to timber construction interior wall. The sound absorption coefficient was measured by impedance tube method and compared with Helmholtz resonance structural layer, solid structural layer and air layer in traditional wall. The results show that the combination of the spiral structural layer and the wall can optimize the sound absorption performance of the wall in the medium and low frequency. Without reducing the overall sound-absorbing performance of the wall, can achieve perfect sound absorption in some medium and low frequency sound bands.

Parametric Influence on the Sound Absorption Coefficient of Porous Asphalt

2009 ◽  
Author(s):  
Punnamee Sachakamol ◽  
Liming Dai
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Prediction Models ◽  
Traffic Noise ◽  
Acoustic Properties ◽  
Sound Absorption Coefficient ◽  
Control Parameters ◽  
Porous Asphalt ◽  
Pavement Materials ◽  
Impedance Tube Method

This research intends to develop a method for predicting the sound absorption coefficient of various porous highway pavement materials. Since many of the existing prediction models for acoustic properties and traffic noise still have limitations and problems with accuracy, sound absorption coefficients are measured with the impedance tube method to verify numerical values obtained from the model. Results obtained from the experiment and numerical simulations are compared and presented to reveal the effect and influence of the control parameters.

A model for the sound absorption coefficient of multi-layered elastic micro-perforated plates

2018 ◽  
Vol 430 ◽  
pp. 75-92 ◽  
Author(s):  
Hyun-Sil Kim ◽  
Pyung-Sik Ma ◽  
Sang-Ryul Kim ◽  
Seong-Hyun Lee ◽  
Yun-Ho Seo
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Sound Absorption Coefficient ◽  
Perforated Plates

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.

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