• The Journal of the Acoustical Society of Korea
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• v.35 no.6
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• pp.491-500
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• 2016

The present study describes the acoustical characteristics of the new noise barriers which can control not only noise but also wind pressure by allowing air flow through barriers. In order to investigate the sound reduction index of the air transparent noise barrier, 17 models in total were examined with various size of openings and the volume of the resonators. As a result, it was found that the sound reduction index varies with the volume of the resonator and the area of the openings. Also, it was revealed that double layer of units has more sound reduction index than the single layer of unit at the frequency band from 400 Hz to 1250 Hz. This denoted that physical features of openings and resonators affect the sound reduction index of the air transparent noise barrier.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.124-134
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• 2016

Research on low height noise barriers installed adjacent to railways to reduce the height of the noise barrier has actively progressed in many countries except Korea. The performance of low height noise barriers is evaluated to identify barrier acoustic characteristics using a scale model of the barrier in the present research. As shown in the experimental results, if it is considered the installation of 'ㄱ' type noise barrier, sound absorption material should be installed on both the top and the vertical surfaces of the barrier to improve insertion loss. Also, an analytical method such as the boundary element method, rather than a simple empirical equation, is required to evaluate the insertion loss of the barrier. In addition, noise level increase in passenger position is very small if a barrier with sound absorption material is installed. Finally, the two dimensional boundary element method is implemented to predict the acoustic characteristics of the low height barrier; the possibility of the application is confirmed from a comparison of the results of measurements and predictions.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.11
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• pp.1099-1105
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• 2012

Transparent noise barrier panels have the advantages of transmitting light to nearby residents and allowing drivers to orientate themselves by providing views of the surrounding area. To develop guidelines on quality criteria for transparent soundproof panels, their sound transmission loss and weatherability were experimentally investigated. In Korea, the sound transmission loss of noise barrier panels should be more than 25 dB at 500 Hz and 30 dB at 1000 Hz. The transmission loss tests of transparent panels were performed in accordance with KS F 2808. Typically, plastic materials suffer from color changes when exposed to ultraviolet(UV) light over extended periods. Therefore, weathering of plastics is one of the most important properties for outdoor applications. Protection against UV radiation and weathering is usually accomplished by using UV stabilizer additives or coatings. Transparent materials for soundproof panels were examined through accelerated weathering tests and their weathering resistances were evaluated from changes in yellowness index.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.103-108
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• 2001

The structure of hard disk drive(HDD) is excited by dynamic motion of a disk-spindle motor, and it makes sound noise. Therefore, the cover and the base of HDD should be designed to reduce noise and vibration induced by spindle motor. The prediction technique of sound pressure level(SPL) of a given structural shape enables us to design a cover and a base with much less vibration and noise. In this paper, we measured the force of disk-spindle motor and predicted SPL from HDD by computational simulation. To get a SPL of HDD by computational simulation, modal analysis and forced vibration analysis were performed with ANSYS, and sound radiation was computed using SYSNOISE. The calculated results were compared with experimental results and a good agreement was obtained. With this computer simulation procedure and design of experiment(DOE), optimal thickness of noise barrier and damper was calculated.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.718-723
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• 2004

The insertion loss of a noise barrier comes from the effects of diffraction, transmission loss, absorption coefficient and attenuation by direct propagation. The noise level after the noise barrier, differs reatly from the diffraction on the upper part of the barrier. Maekawa, furze and Anderson presented a empirical formula for calculating the diffraction of a semi infinte screen shaped noise barrier. In this syudy, Noise reduction performance software was developed for the proper design and assessment of new plastic barrier . Predicted sound pressure level from using the software is compared with the site-measurement results to verify the noise reduction performance and feasibility of prediction software for insertion loss of noise barrier.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.241-242
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• 2023

This paper discusses an innovative acoustic membrane developed by doAZ Co., Ltd., offering enhanced noise barrier and dust control for urban construction and demolition, surpassing the performance of traditional non-woven fabrics. The membrane is made from recyclable bubble sheets and designed to be seamlessly integrated into single and double-row scaffolding systems, ensuring broader applicability and sustainability.

• Journal of the Korea Concrete Institute
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• v.20 no.5
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• pp.653-660
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• 2008

The purpose of this study is to analyze the optimal mix design of the sound absorption material that is made from perlite and various binder systems for noise barrier wall. The polymer cement slurry which is made from two types of polymer dispersions, and silicone type inorganic material are used as binder. The test specimens are prepared with various polymer cement ratios, binder ratios, and tested for strengths, freezing and thawing and sound absorption performance by the tube and the reverberation room methods. From the test results, the difference of sound absorption coefficient by the tube method is a little recognized, however, noise reduction coefficient (NRC) of test specimens bound by the polymer cement slurry is in the ranges of 0.48 to 0.51. They are a little higher than those bound by cement only, and are lower values than recommended value of 0.7 by the Ministry of Environment. However, the sound absorption coefficient of test specimens at low frequency range of 250 to 500 Hz by reverberation room method shows very high values as 0.84 to 1.00, and 0.57 to 0.77 at the high frequency. The test specimens with polymer cement slurry binder have a good balance between performance and cost, and have proper properties in strengths, freezing and thawing resistance as sound absorption material for noise barrier wall. It is apparent that the good sound absorption material can be produced according to the optimum mix design that is recommended from this study.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2009.11a
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• pp.213-216
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• 2009

The purpose of this study is analyzing temporal flow about 20 detailed performance items in the "Housing Performance Grading Indication System". This study try to figure out situations according grade in detailed performance item and to analyze change item about 112 cases(2 cases in 2006, 15 cases in 2007, 46 cases in 2008, 49 cases in 2009), from January 9, 2006 which system is undertaken, to October, 2009. This system consists of 5 main performance section, 14 performance categories and 20 detailed performance items. 5 main performance parts are Noise and Acoustics(Light-weight impact sound control, heavy-weight impact sound control, sound control of toilet, sound control of party wall), Long-life(flexibility, remodeling & maintenance, durability), Landscape & Indoor Environment(landscape, formaldehyde control & ventilation, daylighting, thermal environment), Welfare & Barrier-free(playground and community center, welfare space, barrier-free design), Fire Safety(fire safety, safe place, fire-resisting quality). Total efficiency about housing can understand systematically of 20 perfomance items though this research.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.479-482
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• 2008

The purpose of this study is a proposal about the flexibility of the performance category to revitalize the "Housing Performance Grading Indication System". This system consists of 5 main performance parts, 14 performance categories and 20 detailed performance lists. 5 main performance parts are Noise and Acoustics(Light-weight impact sound control, heavy-weight impact sound control, sound control of toilet, sound control of party wall), Long-life(flexibility, remodeling & maintenance, durability), Landscape & Indoor Environment(landscape, formaldehyde control& ventilation, daylighting, thermal environment), Welfare & Barrier-free(playground and community center, welfare space, barrier-free design), Fire Safety(fire safety, safe place, fire-resisting quality). The flexibility of the performance category is conformed to Long-life housing related grading and can realize the Long-life housing in response to resident needs about the space rearrangement. Now, The flexibility of the performance category is limited to the evaluation of the private space, that is, the Skeleton evaluation. This study would suggest alternatives to improve uppermost limits through analyzing 60 examples from January 9th 2009 to October 30th 2008. The flexibility of the performance category is possible to estimate not only the Skeleton evaluation but also the Infill evaluation in response to social changes.

• Journal of KSNVE
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• v.10 no.3
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• pp.423-429
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• 2000

This paper investigates the use of boundary element method(BEM) to analyze the insertion loss of a noise barrier. To begin with the validity of the BEm for the analysis of noise barrier insertion loss in checked by both Lam's theoretical method and the measurements in the anechoic chamber for the scale-down models. Through simulation it is shown that using 2D BEM model is sufficient to the analysis for the barrier with large ratio of length to height. By using 2D BEM model the insertion loses are predicted for the real noise barriers in several cases which are the case that they are built parallel on both roadsides the one that there are multiple sound sources and the one that there is a gap between a concrete structure and a barrier plate.