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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society for Noise and Vibration Engineering
Journal Basic Information
Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 24, Issue 12 - Dec 2014
Volume 24, Issue 11 - Nov 2014
Volume 24, Issue 10 - Oct 2014
Volume 24, Issue 9 - Sep 2014
Volume 24, Issue 8 - Aug 2014
Volume 24, Issue 7 - Jul 2014
Volume 24, Issue 6 - Jun 2014
Volume 24, Issue 5 - May 2014
Volume 24, Issue 4 - Apr 2014
Volume 24, Issue 3 - Mar 2014
Volume 24, Issue 2 - Feb 2014
Volume 24, Issue 1 - Jan 2014
Selecting the target year
Analysis of Acoustic Characteristics and Shooting Noise Prediction for Shooting Range Soundproofing in Military
Jeong, A-Yeong ; Kim, Jae-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 833~839
DOI : 10.5050/KSNVE.2014.24.11.833
The shooting noise caused by shooting training, which has strength and impacts, is becoming a serious damage to the residents around the shooting range and, consequently, the number of civil appeals against the shooting noise is on the constant increase. For this reason, the military examines the effects of the shooting noise at the stage of design in constructing a shooting range and tries to build a soundproof shooting range to minimize civil appeals. However, the lack of research and data concerning propagation and attenuation, both of which characterize the shooting noise from within a soundproof shooting range, even makes it so difficult to design a soundproof shooting range in constructing it. So this study used an acoustic simulation in a soundproof shooting range to identify acoustic and propagation characteristics within the shooting range and, on this basis, predicted the noise level at an exit of the soundproof shooting range. As a result, if the form and specifications of a soundproof shooting range were decided on at the stage of design, it was possible to use a simulation to design a soundproof shooting range with optimized acoustic performance and, on this basis, to predict a sound pressure level at an exit of the soundproof shooting range. On the basis of these data, it is probably possible to determine the degree of the effects of the shooting noise on the villages around a shooting range and the extent of damage to it and to minimize civil appeals against the shooting noise and resolve the issues of compensation and agreement with ease. This study is expected to provide useful data for designing and constructing a similar soundproof shooting range.
Analysis of Spectral Fatigue Damage of Linear Elastic Systems with Different High Cyclic Loading Cases using Energy Isocline
Shin, Sung-Young ; Kim, Chan-Jung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 840~845
DOI : 10.5050/KSNVE.2014.24.11.840
Vibration profiles consist of two kinds of pattern, random and harmonic, at general engineering problems and the detailed vibration test mode of a target system is decided by the spectral condition that is exposed under operation. In moving mobility, random responses come generally from road source; whereas the harmonic responses are triggered from rotating machinery parts, such as combustion engine or drive shaft. Different spectral input may accumulate different damage in frequency domain since the accumulated fatigue damage dependent on the pattern of input spectrum in high cyclic loading condition. To evaluate the sensitivity of spectral damage according to different loading conditions, a linear elastic system is introduced to conduct a uniaxial vibration testing. Measured data, acceleration and strain, is analyzed using energy isocline function and then, the calculated fatigue damage is compared by different loading cases, random and harmonic.
Development of High Performance Intake Silencer Using Swirling Flow for Household Oxygen Generators
Kim, Seong-Hun ; Lee, Gwang-Se ; Choi, Yong-Bok ; Cheong, Cheolung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 846~853
DOI : 10.5050/KSNVE.2014.24.11.846
High performance intake silencer with low pressure drop are developed for a household oxygen generator. First, the acoustic power of the target oxygen generator are experimentally evaluated according to ISO code. Then, the transmission loss of and the flow characteristics inside the existing intake silencer are predicted and analyzed. On a basis of these results, two intake silencers are proposed, which are designed to induce the swirling flow inside the intake silencer and thus to reduce the flow loss. The predicted TL and the pressure drop for these two new silencers are compared to the existing one, which shows that the proposed ones have higher TL as well as low pressure drop. The reason for these improvements are explained by investigating the flow characteristics of the new silencers in detail.
Workers` Exposure Characteristics to Noise in Car Inspection Processes
Jang, Jae-Kil ; Kim, Jong-Kyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 854~860
DOI : 10.5050/KSNVE.2014.24.11.854
Workers engaged in car inspection works have been exposed to many occupational hazards including noise, particulate matter, and volatile organic substances. Noise-induced hearing loss(NIHL) is one of the leading health hazards among Korean workers. The aim of this study is to evaluate the noise levels in several car inspection shops by introducing the evaluation methods of KMOEL/OSHA and ACGIH. Six sites in central area of Korea were selected to monitor the noise levels of workers by personal and area sampling methods for two consecutive days in spring, summer, fall and winter seasons. Dosimeters have been used for this noise monitoring program. Obtained noise levels by the evaluation method according to KMOEL/OSHA are the range of 50.2~88.2 dB(A), these are lower than KOEL/OSHA standards level of 90 dB(A). But highest noise by ACGIH`s evaluation methodology is recorded 92.3 dB(A) and is greater than NIHL standard level of 85 dB(A). So that many workers may be exposed to the dangerous noise environment. The higher the car inspection loads daily, the higher the noise levels in the sites. Seasonal fluctuation of noise levels at the process might give monitoring results with high variations. Area noise levels showed higher than those of personal sampling, which illustrate some high noise spots in the car inspection areas.
A Study on Semi-active Vibration Isolation Table using a Nonlinear Analysis of the MR Damper
Kim, DoYoung ; Chun, ChongKeun ; Kwon, YoungChul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 861~867
DOI : 10.5050/KSNVE.2014.24.11.861
In this study, a semi-active isolator was constructed from applying a MR damper that used the MR fluid to an isolator. The parameter identification was also performed to determine the characteristics of this semi-active isolator during which the least squares method and the auxiliary variable method were applied to produce a value closest to the true value. In addition, the MR damper`s nonlinear damping force was closely analyzed to greatly reduce the range of error. Based on this analysis, it was discovered that the parameter tended to increase with more electric current. Such analysis of the dynamic properties of semi-active isolator proved that constructing an isolator that provides a more stable operation could be achieved.
A Study on the Echo Reduction Performance of Underwater Acoustic Material
Seo, Young Soo ; Ham, Il Bae ; Jung, Woo Jin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 868~875
DOI : 10.5050/KSNVE.2014.24.11.868
The requirement of acoustic material which is used in underwater environment more increases. The material is used to reduce acoustic signature and radiate noise for underwater vehicle. Underwater acoustic material was made by viscoelastic material such as rubber and polyurethane etc. The mechanical and acoustic characteristics of these material change with hydrostatic pressure. In order to improve an acoustic performance according to hydrostatic pressure, several kinds of scatterers were added to viscoelastic material. In this paper, acoustic modelling and analysis techniques of underwater acoustic material with hydrostatic pressure were introduced and proposed. The specimens for pulse tube test were made and echo reductions were calculated and measured with hydrostatic pressure. Also the characteristics of echo reduction of the specimens with hydrostatic pressure were obtained and discussed.
Prediction of Total Acoustic Radiation Power of the Submerged Circular Cylindrical Structures
Han, Seungjin ; Lee, Jongju ; Kang, Myunghwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 876~882
DOI : 10.5050/KSNVE.2014.24.11.876
This study investigates an efficient method to estimate the total acoustic radiation power of submerged circular cylindrical structures. Since the acoustic radiation power of submerged vehicles can be changed during the operation, the estimation for its monitoring onboard is required to accomplish the missions. The total acoustic radiation power is estimated using the measured velocity and the calculated radiation efficiency of the surface which consists of submerged rectangular plate elements. Experiments are carried out to validate the estimation approach. Comparisons of the estimation results with the measurements show that they are in a good agreement for the mid-high frequency range and match well for the cases of different excitation locations which correspond to the different operation modes of underwater vehicles as well. Therefore, this estimation method can be applied effectively to the development of the radiated noise monitoring-system.
Numerical Analysis of Noise Reduction and Back-pressure for a Simple Expansion Chamber with a Partition
Kim, Yeon Woo ; Jeong, Weuibong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 883~889
DOI : 10.5050/KSNVE.2014.24.11.883
Mufflers have been widely used in the exhaust system to reduce the noise. However, installing muffler may deteriorate the efficiency due to the increase of back pressure. Mufflers usually consist of partition plates and perforated holes in a expansion chamber. In this paper, the influences of the location of the partition and hole on the acoustic TL and back pressure were examined. The acoustic TL was predicted using virtual lab commercial software, while the back pressure were predicted using CFX commercial software. The results were used to set up a database for finding their trends. The optimal muffler model in user-interested frequency range could be selected by analyzing this database.
Performance Characteristics of Vibration Energy Harvesting Using  and -Poled PMN-PZT Single Crystals
Kim, Jae Eun ; Kim, Young-Cheol ; Sun, Kyung Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 890~897
DOI : 10.5050/KSNVE.2014.24.11.890
This work investigated the electromechanical performance of a cantilevered vibration energy harvester incorporating the single crystal PMN-PZT, manufactured with the most recent technology of solid-state single crystal growth. The performances of single crystal PMN-PZTs with two different crystallographic axes such as  and  are compared with those of PZT ceramics. From the investigations, it is shown that the -poled PMN-PZT is advantageous for the excitations containing single dominant frequency component, while the single crystal -
is superior in terms of the energy storage density and energy conversion efficiency.
Straight-line Path Error Reduction for the End of a Flexible Beam Deploying from a Rotating Rigid Hub
Kim, Byeongjin ; Kim, Hyungrae ; Chung, Jintai ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 898~906
DOI : 10.5050/KSNVE.2014.24.11.898
This paper presents a reduction method for a straight-line path error of a flexible beam deploying from a rotating rigid hub. Previous studies discussed about only vibration phenomena of flexible beams deploying from rotating hubs; however, this study investigates a vibration reduction of a rotating beam with variable length. The equation of motion and associated boundary conditions are derived for a flexible beam deploying from a rotating rigid hub, and then they are transformed to a variational equation. By applying the Galerkin method, the discretized equations are obtained from the variational equation. Based on the discretized equations, the dynamic responses of a rotating/deploying beam are analyzed when the beam end has a straight line motion. A reduction method for the trajectory error is proposed, using the average length of a rotating/deploying beam. It is shown that the proposed method is able to reduce the residual vibration of a rotating/deploying beam.
A Analysis on the Estimation Method of the 3D Underwater Radiation Noise Pattern of Cylindrical Structure with the Underwater Experiments
Yi, Jongju ; Kang, Myunghwan ; Han, Seungjin ; Jeong, Hyunjoo ; Oh, Junseok ; Bae, Sooryong ; Jung, Woojin ; Seo, Young Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 11, 2014, Pages 907~918
DOI : 10.5050/KSNVE.2014.24.11.907
In this study for the prediction of 3D underwater radiated noise pattern, a comparison between the proposed method(DHIE, Discrete Helmholtz Integral Equation) and the 3D underwater radiated noise calculation results using the measurement of near-field acoustic pressure data is performed. The near-field acoustic pressure in water is measured for the calculation of the far-field radiated noise pattern and the far-field acoustic power. Also the vibration field of the underwater structure is measured in simultaneously. Using the total far-field acoustic power and the vibration field on the surface of the structure, the proposed method(DHIE) can predict the underwater radiated noise pattern of the far-field The predicted results show the reasonable agreement within about 5dB comparing with the experiment result.