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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 17, Issue 12 - Dec 2007
Volume 17, Issue 11 - Nov 2007
Volume 17, Issue 10 - Oct 2007
Volume 17, Issue 9 - Sep 2007
Volume 17, Issue 8 - Aug 2007
Volume 17, Issue 7 - Jul 2007
Volume 17, Issue 6 - Jun 2007
Volume 17, Issue 5 - May 2007
Volume 17, Issue 4 - Apr 2007
Volume 17, Issue 3 - Mar 2007
Volume 17, Issue 2 - Feb 2007
Volume 17, Issue 1 - Jan 2007
Selecting the target year
Comparison of Absorption Coefficient according to Test Methods
Lee, J.W. ; Gu, J.H. ; Park, H.K. ; Kang, Dae-Joon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 373~378
DOI : 10.5050/KSNVN.2007.17.5.373
Today, the use of the sound absorptive material is increasing to improve the room acoustics in the auditorium and music hall, etc. Usually, the sound absorption materials have been used to enhance the performance of a noise barrier and improve the room acoustics in construction site. Generally, the sound absorbtion coefficients are the most important factor reflecting the sound absorbtion performance. There are two methods to measure the sound absorption coefficient. The first one is the reverberation room method, and the second is the impedance tube method. In this study, we measure the sound absorbtion coefficients using these two methods, and then we compared the results of the sound absorbtion coefficients to look into the difference of results between reverberation room method and impedance tube method. Also we compared the results of the sound absorbtion coefficients with respect to the size of sample and the volume of reverberation room. From the experiment, we could see that the sound absorbtion coefficients are measured equally for different sample size. But the sound absorbtion coefficients are measured differently according to test methods and test conditions.
A Study on the Establishments of Aircraft Noise Abatement Procedures in Gimpo International Airport
Kim, Yeon-Myung ; Park, Jin-Woo ; Kim, Young-Il ; Son, Jung-Gon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 379~390
DOI : 10.5050/KSNVN.2007.17.5.379
The final purpose of this study is to develop noise abatement procedures for minimizing damages caused by aircraft noise, to establish appropriate noise limits and to suggest a plan for imposing surcharges and penalties on aircraft infringing the noise limits. This study establishes noise abatement procedures and suggests a plan to complement and improve upon NMS in Gimpo International Airport by reviewing the NMS structure. In addition, this study establishes a noise limit at each noise monitoring system and a verification system to discriminate infringing aircraft. Finally, this study suggests a control plan for aircraft Infringing the noise limit.
Design of Hybrid Mount Using Rubber Element and Piezoelctric Actuator with Application to Vibration Control
Yook, Ji-Yong ; Sung, Kum-Gil ; Moon, Seok-Jun ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 391~397
DOI : 10.5050/KSNVN.2007.17.5.391
This paper presents active vibration control using a hybrid mount which consists of rubber element and the piezostack actuator. After identifying stiffness and damping properties of the rubber element and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then incorporated with the vibration system, and the governing equation of motion is obtained in a state space. A sliding mode controller and LQG controller are designed in order to actively attenuate the vibration of the system subjected to various frequencies and small magnitude excitations. Control responses such as acceleration and force transmission through the hybrid mount are evaluated by computer simulation.
Study of the Annoyance Sensitivity for the Frequency Band of Road Traffic Noise
Jo, Kyoung-Sook ; Hwang, Dae-Sun ; Cho, Yeo ; Hur, Deog-Jae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 398~404
DOI : 10.5050/KSNVN.2007.17.5.398
In this study, the sensitivity of annoyance was investigated by the subjective jury test for the variations of the frequency components along with various sound pressure levels of sixteen environmental noise sources. Annoyance was, also, evaluated for the road traffic noises. Sound pressure levels were
which individually divided frequency components with eight bands of equally three bark bands. The results show that vehicle traffic noise is recognized as the most serious environment noise source. The sensitivity of human perception of annoyance in frequency bands is quite different from A-weighting curve. The annoyance found out to be more sensitive in high frequency region and reached its maximum in 3.4 kHz.
A Study on Turbulent Wall Pressure Fluctuations Using a Coherent Structure Model
Ahn, Byoung-Kwon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 405~414
DOI : 10.5050/KSNVN.2007.17.5.405
In recent years, experimental and theoretical studies show that turbulent flows looking disordered have a definite structure produced repetitively with visible order. As a core structure of turbulence, hairpin vertices are believed to play a major role in developing and sustaining the turbulence process in the near wall region of turbulent boundary layers and may be regarded as the simplest conceptual model that can account for the essential features of the wall pressure fluctuations. In this work, fully developed typical hairpin vortices are focused and the associated surface pressure distributions and their corresponding spectra are estimated. On the basis of the attached eddy model, the overall surface pressure spectra are represented in terms of the eddy size distribution. The model is validated by comparison of predicted wavenumber spectra with existing empirical models, the results of direct numerical simulation (DNS) and also spatial correlations with experimental measurements.
Dynamic Balancing in a Link Motion Punch Press
Suh, Jin-Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 415~426
DOI : 10.5050/KSNVN.2007.17.5.415
In a link motion punch press, numerous links are interconnected and each link executes a constrained motion at high speed. As a consequence, dynamic unbalance force and moment are transmitted to the main frame of the press, which results in unwanted vibration. This degrades productivity and precise stamping work of the press. This paper presents an effective method for reducing dynamic unbalance in a link motion punch press based upon kinematic and dynamic analyses. Firstly, the kinematic analysis is carried out in order to understand the fundamental characteristics of the link motion mechanism. Then design variable approach is presented in order to automate the model setup for the mechanism whenever design changes are necessary. To obtain the inertia properties of the links such as mass, mass moment of inertia, and the center of mass, 3-dimensional CAD software was utilized. Dynamic simulations were carried out for various combinations of design changes on some links having significant influences on kinematic and dynamic behavior of the mechanism.
Analysis of Contact and Separation between the Catenary and the Pantograph of a High-speed Electrical Train Considering the Dropper Positions
Lee, Ki-Su ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 427~436
DOI : 10.5050/KSNVN.2007.17.5.427
The catenary of a high-speed electrical train is modeled by the finite elements with the upper suspension wire, lower contact wire, and droppers, and the dynamic contact between the catenary and the pantograph is numerically analyzed by solving the whole equations of motion of the pantograph and the catenary system subjected to the contact condition. For the stability of the numerical solution, with the cubic spline interpolation of the catenary displacement, the velocity and acceleration constraints as well as the displacement constraint are imposed on the contact point. Through the various numerical examples, it is shown that the dropper positions as well as the static deflection are crucial to determine the contact and separation of the pantograph of a high-speed train.
Comparison between Indoor Noise Level and Subjective Response for Transportation Noise - Focusing on the Aircraft, Road traffic and Railway Noise
Park, Hyeon-Ku ; Kim, Sun-Woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 437~447
DOI : 10.5050/KSNVN.2007.17.5.437
A series of research to seek for the relationship between subjective responses and noise level for transportation noise have been proceeded, and their results showed similar for some cases and different for some other cases as well, which is considered due to the various conditions such as the way of survey, different scale applied, and country etc. This study aimed to analyze the relationship between sound level and subjective response for the different kinds of transportation noise. The noises recorded in real situation were played to thirty subjects with fourty nine adjectives. The percentage of people annoyed(% PA) and the percentage of people highly annoyed(% HA) were calculated from the subjective results and compared how many percent of people are annoyed and highly annoyed for the same sound level. As a result of calculating the average, the aircraft noise was highest and the white noise lowest. The relationship between window TL and average point was well correlated except the aircraft noise which was scattered because of high sound level at specific frequency and low TL at corresponding frequency. This means that appropriate rating method for airborne sound transmission should be sought for to evaluate outdoor noise which has different frequency characteristics. The Boltzmann equation for % PA and % HA was applied to predict the sound level corresponding to the percentage. It is concluded that the aircraft noise and road traffic noise have almost same response and the railway noise was same with white noise, used for the reference noise, annoyed lower than other noises about by 3 dB.
Evaluation of Operation Reliability for Micro Gas Turbine(MGT) Power Generation System
Kim, Jae-Hoon ; Hur, Kwang-Beom ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 448~455
DOI : 10.5050/KSNVN.2007.17.5.448
As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. This paper describes the procedures and results for the mechanical, electrical, and environmental tests of MGT on actual grid-connection under Korean regulations. As one of the achievements, the simulation model of MGT was developed, so that it will be able to analyze or propose new distributed generation system using MGT. The field test was conducted in order to respond to a wide variety of needs for noise reduction and utilization and its performance was evaluated in consideration of its operational problems. The MGT is successfully supplying electricity to Korean grids with satisfying various regulations. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.
A Study on Golf Ball Spin Mechanism at Impact
Roh, Woo-Jin ; Lee, Chong-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 456~463
DOI : 10.5050/KSNVN.2007.17.5.456
It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and force. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail in the literature. In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.
Maneuver Analysis of Full-vehicle Featuring Electrorheological Suspension and Electrorheological Brake
Sung, Kum-Gil ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 17, issue 5, 2007, Pages 464~471
DOI : 10.5050/KSNVN.2007.17.5.464
This paper presents a maneuver analysis of a full-vehicle featuring electrorheological(ER) suspension and ER brake. In order to achieve this goal, an ER damper and an ER valve pressure modulator are devised to construct ER suspension and ER brake systems, respectively. After formulating the governing equations of the ER damper and ER valve pressure modulator, they are designed and manufactured for a middle-sized passenger vehicle, and their field-dependent characteristics are experimentally evaluated. The governing equation of motion for the full-vehicle is then established and integrated with the governing equations of the ER suspension and ER brake. Subsequently, a sky-hook controller for the ER suspension and a sliding mode controller for the ER brake are formulated and implemented. Control performances such as vertical displacement and braking distance of vehicle are evaluated under various driving conditions through computer simulations.