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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
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Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 23, Issue 12 - Dec 2013
Volume 23, Issue 11 - Nov 2013
Volume 23, Issue 10 - Oct 2013
Volume 23, Issue 9 - Sep 2013
Volume 23, Issue 8 - Aug 2013
Volume 23, Issue 7 - Jul 2013
Volume 23, Issue 6 - Jun 2013
Volume 23, Issue 5 - May 2013
Volume 23, Issue 4 - Apr 2013
Volume 23, Issue 3 - Mar 2013
Volume 23, Issue 2 - Feb 2013
Volume 23, Issue 1 - Jan 2013
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Running Safety Analysis of Railway Vehicle passing through Curve depending on Rail Inclination Change
Kim, Moon Ki ; Eom, Beom Gyu ; Lee, Hi Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 199~208
DOI : 10.5050/KSNVE.2013.23.3.199
So far today, there is a speed limit by the radius of curve based on operation regulation in domestic railway, however a study for the maximum running speed at the curved section without any derailment would be necessary. The two major factors related to the running safety of railway vehicle are classified as the railway vehicle condition and the track condition. In terms of the rail inclination among many other factors, the determination of rail inclination within the possible limit is necessary for the geometrical structure of the optimum track. The disregard of the geometrical parameter related to the rail inclination may cause a serious problem to the running safety of railway vehicle. This study is focusing on the analyzing of running safety regard to the change of rail inclination among the many other parameters to improve derailment safety, so that there is an affection analysis of the running safety regard to the change of rail inclination in the ideal and geometric track condition. Also There is an affection analysis of the running safety regard to the simultaneous change of rail inclination and the running speed at the curved section. According to analysis results of running safety, In case that the left and right rail inclination are 1/40, the running safety of this condition defined than other conditions. Also, the rail inclination of conventional lines is 1/40, Therefore, the railway vehicle passing through curve is safe when the railway vehicle runs in conventional lines.
Optimal Design of New Magnetorheological Mount for Diesel Engines of Ships
Do, Xuan-Phu ; Park, Joon-Hee ; Woo, Jae-Kwan ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 209~217
DOI : 10.5050/KSNVE.2013.23.3.209
This paper presents an optimal design of a magnetorheological(MR) fluid-based mount(MR mount) that can be used for to vibration control in diesel engines of ships. In this work, a mount that uses mixed-modes(squeeze mode, flow mode, and shear mode) is proposed and designed. To determine the actuating damping force of the MR mount required for efficient vibration control, the excitation force from a diesel engine is analyzed. In this analysis, a model of a V-type engine is considered. The relationship between the velocity and pressure of gas in terms of the torque acting on the piston is derived. Subsequently, by integrating the field-dependent rheological properties of commercially available MR fluid with the excitation force, the appropriate size of the MR mount is designed. In addition, to achieve the maximum actuating force under geometric constraints, design optimization is undertaken using the ANSYS parametric design language software. Through magnetic density analysis, optimal design parameters such as the bottom gap and radius of coil are determined.
Study on the Effects of the Mounting Direction of Vertically-launched Missiles in Vibration Tests
Lee, Hojun ; Kim, Ki-Eun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 218~225
DOI : 10.5050/KSNVE.2013.23.3.218
Vertically-launched missiles are supported as erected vertically in the vertical launching system of warship, and they should be mounted in the same way when vibration-tested. However, mounting missiles vertically makes a fixture, which is a supporting structure, bulky and heavy so requiring a high-performance exciter. Mounting missiles as laid down horizontally in a vibration test is economical regarding fixture manufacturing and exciter performance, but it makes test results incorrect because the different mounting direction has effects on the test results. A bending moment due to missiles' weight happens to missiles, and resilient mounts, which support missiles in the vertical launch system, deflect differently from the real situation because of the static deflection of these mounts due to missiles' weight. If the resilient mounts supporting missiles have nonlinear force-deflection characteristics, vibration test results become more different from the true results. This paper proposes to support missiles with an additional resilient mount such as a bunge code in order to solve those problems coming from mounting vertically-launched missiles as laid down horizontally in vibration tests. The proposed approach enables to obtain the same test results as in their actual mounting condition even though vertically-launched missiles are mounted in a different direction.
Boundary Element Analysis for Individual Acoustic Responses in Ear Canal of Korean Adults
Lee, Dooho ; Ahn, Tae-Soo ; Son, Young-Seok ; Shin, Jeeyoung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 226~233
DOI : 10.5050/KSNVE.2013.23.3.226
Individual differences in head-related transfer functions(HRTFs) were calculated using boundary element(BE) models for three Korean adults. The BE models for the individuals were developed from the computerized tomography(CT) images of the individuals. The BE models were composed of the head, pinna, and ear canal. The frequency-dependent impedance boundary conditions were imposed on the skin, hair, and tympanic membrane. The HRTFs calculated from the individual BE models showed large difference above 2 kHz in magnitude and in the locations of peaks and valleys of the frequency spectrums, which should be considered in virtual auditory sound field. The identified individual differences in the HRTFs demonstrate that the developed BE models can be utilized successfully in order to obtain the HRTFs information of individuals.
Vibration Analysis of Planetary Fixed Outer-ring Type Cycloidal Speed Reducer by using Multi-body Modeling
Kim, Hong Ki ; Lee, Ki Bok ; Yoo, Hong Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 234~239
DOI : 10.5050/KSNVE.2013.23.3.234
There are many types of speed reducer for industrial uses. However the cycloid speed reducer is widely used in manipulators based on excellent performance of low backlash, high reduction ratio and compact size. It is essential to use precision speed reducer for accuracy of position controls on robot systems and electric vehicles. The cycloid speed reducer has a eccentric rotating motion and offset to avoid some problem of assembly, so it has a disadvantage for vibration. In this paper, a multi-body dynamic model is developed for a cycloid speed reducer and the dynamic behaviors of the reducer are investigated. The cycloid speed reducer consists of cycloidal plate gears, housing gear, input shaft, output pin and shaft, and eccentric bearings. Using a CAD program, each component of cycloid reducer is modeled based on the offset and eccentric. Multi-body simulations using Recurdyn and test using a rig tester are performed. As a result, the pin reaction force and the amplitude of housing displacement are increased by the larger offset and smaller eccentric value of cycloid reducer.
Study on the Dynamic Characteristics of a Manual Transmission Using Linear Models
Yoon, Jong-Yun ; Lee, Iljae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 240~248
DOI : 10.5050/KSNVE.2013.23.3.240
Torsional vibrations, such as the gear rattle of the manual transmission in vehicle systems, are correlated with the firing stroke from the engine. These vibro-impacts can be examined based upon linear time-invariant analysis. In order to understand the gear dynamics, a specific manual transmission with a front-engine front-wheel drive configuration is investigated. A method to reduce the degrees of freedom is suggested based upon the eigensolutions and frequency response functions, which will lead to the development of an efficient matrix size. The dynamic characteristics of single- and dual-mass flywheels are then compared. The effect of the dual-mass flywheel is investigated based upon the mobility analysis, which will lead to understanding of the concepts for avoiding vibro-impacts. A linear time-invariant system model is examined by employing the effective clutch stiffness from a two-stage clutch damper. Thus, the relationship between the dynamic characteristics and the clutch damper can be predicted by assuming a combination of different stage stiffness levels.
Synthetic Phase Tuning Technique for the Transduction of a Specific Ultrasonic Torsional Mode in a Pipe
Kim, Hoe Woong ; Kwon, Young Eui ; Joo, Young Sang ; Kim, Jong Bum ; Kim, Yoon Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 249~257
DOI : 10.5050/KSNVE.2013.23.3.249
This study newly presents a synthetic phase tuning technique to suppress the unwanted torsional mode while enhancing the desired torsional mode in a pipe. Specifically, we aim at the enhancement of the first torsional mode and the suppression of the undesired, second torsional mode. Earlier efforts were to enhance the desired wave mode only in the hope that the enhancement results in the suppression of the unwanted wave mode. Unlike these efforts, the suggested technique makes the complete cancellation of the unwanted wave mode but it is shown to enhance the desired first mode for torsional wave problems. In the present study, the synthetic phase tuning is developed for the cancellation of the unwanted wave mode, meaning that the number of necessary experimental equipments is reduced. Simulation and experiment were carried out to check the effectiveness of the proposed method. As an application of the suggested technique, we investigated the reflection and mode conversion characteristics of the first torsional mode according to the step thickness variation in a stepped pipe.
Psychoacoustical Analysis and Application of Electroencephalography(EEG) to the Sound Quality Analysis for Acceleration Sound of a Passenger Car
Lee, Seung-Min ; Lee, Sang-Kwon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 258~266
DOI : 10.5050/KSNVE.2013.23.3.258
This paper presents the correlation between psychological and physiological acoustics for the automotive acceleration sound. The research purpose of this paper is to evaluate the sound quality of acceleration sound of a passenger car based EEG signal. The previous method for the objective evaluation of sound quality is to use sound metrics based on psychological acoustics. This method uses not only psychological acoustics but also physiological acoustics. For this work, the sounds of 7 premium passenger cars are recorded and evaluated subjectively by 33 people. The correlation between the subjective rating and sound metrics is calculated based on physiological acoustics. Finally the correlation between the subjective rating and the EEG signal measured on the brain is also calculated. Throughout these results the new evaluation system for the sound quality on the automotive acceleration sound of a passenger car has been developed based on bio-signal.
Effects of Generator Retrofit on Torsional Natural Frequency of Turbine-generator Train and Study on Measurement Results
Lee, Hyuk-Soon ; Yoo, Seong-Yeon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 267~273
DOI : 10.5050/KSNVE.2013.23.3.267
Recently, turbine-generators have been replaced for the integrity reinforcement and the efficiency improvement, also, the blade's failures of LP turbines due to torsional vibration have been reported. Excessive torsional vibrations can result in failures of components. The severity of torsional oscillations and stress depends upon the separation margin between the excitation frequencies and torsional natural frequencies. Therefore it is needed to measure the torsional natural frequencies after replacement of the components to conform the separation margin of torsional natural frequencies. In this study torsional vibration measurements were performed after LP turbine and generator replacement and the torsional natural frequencies for the turbine-generator train were calculated to evaluate the effects of generator replacement on torsional natural frequencies of turbine-generator train. It is expected that these evaluation results will be used effectively to identify the root causes of torsional vibration problems.
Floor Impact Sound Pressure Level Characteristics by the Change of Reverberation Time in a Reverberation Chamber
Jeong, Jeong Ho ; Kim, Jeong Uk ; Jeong, Jae Gun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 274~281
DOI : 10.5050/KSNVE.2013.23.3.274
Field measurement method of heavy/soft impact sound pressure level which is regulated in JIS and ISO has been using in Korea, Japan and Canada. It is reported that heavy/soft impact sound pressure level was varied by the sound field condition of receiving room such as sound absorption power and room volume. In this study, it is checked that heavy/soft impact sound pressure level was affected by the receiving sound field condition. Rubber ball and bang machine sound pressure level was measured in the vertically connected reverberation chamber. In oder to check the effect of receiving sound field on heavy/soft impact sound pressure, sound absorption power was changed with polyester sound absorption blankets with air space and glass wool. The reverberation time at 1 kHz band was changed from 10 s to 0.2 s by sound absorption material. Rubber ball sound pressure level measured without sound absorption material was 58 dB in
, but the level was 46 dB with sound absorption treatment. From this result, it is confirmed that sound field correction method is needed in the heavy/soft impact sound pressure level measurement method using bang machine and rubber ball.
Sludge Detection Inside Pipes Using Torsional Guided Waves
Park, Kyung-Jo ; Kim, Chung-Yup ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 3, 2013, Pages 282~290
DOI : 10.5050/KSNVE.2013.23.3.282
A new method is presented that uses guided wave techniques for sludge and blockages detection in long-range pipelines. Existing techniques have the limitations that the sludge position needs to be known a priori and the area to be inspected needs to be accessible. Two guided wave techniques have been developed which allow the sludge or blockages to be detected remotely without the need to access the specific location where the pipe is blocked, nor to open the pipe. The first technique measures the reflection of guided waves by sludge which can be used to accurately locate the blocked region; the second technique detects sludge by revealing the changes to the transmitted guided waves propagating in the blocked region or after it. The two techniques complement each other and their combination leads to a reliable sludge or blockage detection. Various types of realistic sludge have been considered in the study and the practical capabilities of the two techniques have been demonstrated.