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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 15, Issue 12 - Dec 2005
Volume 15, Issue 11 - Nov 2005
Volume 15, Issue 10 - Oct 2005
Volume 15, Issue 9 - Sep 2005
Volume 15, Issue 8 - Aug 2005
Volume 15, Issue 7 - Jul 2005
Volume 15, Issue 6 - Jun 2005
Volume 15, Issue 5 - May 2005
Volume 15, Issue 4 - Apr 2005
Volume 15, Issue 3 - Mar 2005
Volume 15, Issue 2 - Feb 2005
Volume 15, Issue 1 - Jan 2005
Selecting the target year
A Study on the Sound Absorptive Characteristics and Performance of Parallel Perforated Plate Systems
Hong, Byung-Kuk ; Song, Hwa-Young ; Seo, Seong-Won ; Lee, Dong-Hoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1003~1008
DOI : 10.5050/KSNVN.2005.15.9.1003
The acoustic absorption of a multiple layer perforated plate system is very good near the resonance frequency region, while it has been regarded as a demerit that its frequency bandwidth is considerably narrow. In order to overcome such a demerit, the parallel perforated plates with different porosities are proposed. The sound absorption of such system composed of a parallel perforated plate is calculated by an equivalent electroatoustic circuit approach and validated by comparing the calculated absorption coefficients with those measured by the two-microphone impedance tube method. The sound absorptive characteristics and performance of parallel perforated plate systems are discussed from a standpoint of frequency bandwidth related with sound absorption.
FIV Analysis of SG Tubes for Various TSP Locations
Kim, Hyung-Jin ; Park, Chi-Yong ; Park, Myoung-Ho ; Ryu, Ki-Whan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1009~1015
DOI : 10.5050/KSNVN.2005.15.9.1009
Fluid-elastic instability and turbulence excitation for an under developing steam generator are investigated numerically. The stability ratio and the amplitude of turbulence excitation are obtained by using the
(program for integrity assessment of steam generator tube) code from the information on the thermal-hydraulic data of the steam generator. The aspect ratio, the ratio between the height of U-tube from the upper most tube support Plate (h) and the width of two vertical portion of U-tube (w), is defined for geometric parameter study. Several aspect ratios with relocation of tube support plates are adopted to study the effects on the mode shapes and characteristics of flow-induced vibration. When the aspect ratio exceeds value of 1, most of the mode shapes at low frequency are generated at the top of U-tube. It makes very high value of the stability ratio and the amplitude of turbulent excitation as well. We can consider that the local mode shape at the upper side of U-tube will develop the wear phenomena between the tube and the anti-nitration bars such as vortical, horizontal, and diagonal strips. It turns out that the aspect ratio reveals very important parameter for the design stage of the steam generator. The appropriate value of the aspect ratio should be specified and applied.
1/4 Car Vibration Simulation Using an Empirical MR Damper Model
Yang, Bo-Suk ; Lee, Jong-Seok ; Kang, Tae-Ho ; Ryu, Sung-Won ; Baek, Woon-Kyung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1016~1022
DOI : 10.5050/KSNVN.2005.15.9.1016
This study is about a semi-active quarter car simulation method including a MR(magneto-rheological) damper. The MR damper was modeled as Spencer model that can capture nonlinear and hysteretic behavior. The parameters of the Spencer model were extracted from a random excitation test and optimum treatment of the test data. Then, a suspension control algorithm based on Sky-hook theory was applied for the quarter car simulation. Also, an experiment was done using a quarter car simulator to confirm the simulation results with the Spencer MR damper model.
A Study on the Coupled Shaft-torsional and Blade-bending Vibrations in the Flexible Rotor-coupling-blade System
Oh, Byung-Young ; Lee, Sun-Sook ; Yoon, Hyungwon ; Cha, Seog-Ju ; Na, Sungsoo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1023~1029
DOI : 10.5050/KSNVN.2005.15.9.1023
In this paper, a dynamic model for the rotor shaft-coupling-blade system was developed. The blades are attached to a disk and driven by an electric motor shaft which is flexible in torsion. We assumed that the shaft torsional flexibility was lumped in the flexible coupling which is usually adopted in rotor systems. The Lagrangian approach with the small deformation theory for both blade-bending and shaft-torsional deformations was employed for developing the equation of the motion. The Assumed Modes Method was used for estimating the blade transverse deflection. The numerical results highlight the effects of both structural damping of the system and the torsional stiffness of the flexible coupling to the dynamic response of the blade. The results showed strong coupling between the blade bending and shaft torsional vibrations in the form of inertial nonlinearity, stiffness hardening and softening.
Dynamic Analysis of Space Structure by Using Perturbation Method
Seong, Kwan-Jae ; Kwak, Moon K. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1030~1036
DOI : 10.5050/KSNVN.2005.15.9.1030
This paper is concerned with the application of perturbation method to the dynamic analysis of space structure floating in space. In dealing with the dynamics of space structure, the use of Lagrange`s equations of motion in terms of quasi-coordinates were suggested to derive hybrid equations of motion for rigid-body translations and elastic vibrations. The perturbation method is then applied to the hybrid equations of motion along with discretization by means of admissible functions. This process is very tiresome. Recently, a new approach that applies the perturbation method to the Lagrange`s equations directly was proposed and applied to the two-dimensional floating structure. In this paper. we propose the application of the perturbation method to the Lagrange`s equations of motion in terms of quasi-coordinates. Theoretical derivations show the efficacy of the proposed method.
Design of Multi-input Multi-output Positive Position Feedback Controller Based on Block-inverse Technique
Kwak, Moon K. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1037~1044
DOI : 10.5050/KSNVN.2005.15.9.1037
This paper is concerned with the active vibration control of a grid structure equipped with piezoceramic sensors and actuators. The grid structure is a replica of the solar panel commonly mounted on satellites, which contains complex natural mode shapes. The multi-input and multi-output positive position feedback controller is considered as an active vibration controller for the grid structure. A new concept, the block-inverse technique, is proposed to cope with more modes than the number of actuators and sensors. This study also deals with the stability and the spillover effect associated with the application of the multi-input multi-output positive position feedback controller based on the block-inverse technique. It was found that the theories developed in this study are capable of predicting the control system characteristics and its performance. The new multi-input multi-output positive position feedback controller was applied to the test structure using a digital signal processor and its efficacy was verified by experiments.
Development of Lorentz Force Type Integrated Motor-bearing System in Dual Rotor Disk Configuration
Lee, Chong-Won ; Park, Sung-Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1045~1052
DOI : 10.5050/KSNVN.2005.15.9.1045
Tn this paper. dual rotor disk configuration with a coreless stator is proposed for the Lorentz force type integrated motor hearing system. An experimental compensation for the effects of high order harmonics is performed using the digital controller of the experimental setup. The runout profile and rotor unbalance are also identified by the extended influence coefficient method. The experimental results confirm that this compensation scheme effectively attenuates the rotor vibration all over the operating range of rotational speed.
Dynamic Stability Analysis of an Axially Accelerating Beam Structure
Eun, Sung-Jin ; Yoo, Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1053~1059
DOI : 10.5050/KSNVN.2005.15.9.1053
Dynamic stability of an axially accelerating beam structure is investigated in this paper. The equations of motion of a fixed-free beam are derived using the hybrid deformation variable method and the assumed mode method. Unstable regions due to periodical acceleration are obtained by using the Floquet`s theory. Stability diagrams are presented to illustrate the influence of the dimensionless acceleration, amplitude, and frequency. Also, buckling occurs when the acceleration exceeds a certain value. It is found that relatively large unstable regions exist around the first bending natural frequency, twice the first bending natural frequency, and twice the second bending natural frequency. The validity of the stability diagram is confirmed by direct numerical integration of the equations of motion.
An Experimental Study on the Performance Improvement of Industrial Blower Silencer
Kim, B.S. ; Kim, Yong-woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1060~1069
DOI : 10.5050/KSNVN.2005.15.9.1060
Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.
Generating Method of the Input Profile in the MAST System
Lee, Bong-hyun ; Kim, Gi-Hoon ; Kim, Chan-jung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1070~1076
DOI : 10.5050/KSNVN.2005.15.9.1070
Vibration test using the MAST(multi axial simulation table) provide a more reliable testing environment than any conventional one. The multi axial simulation could be possible with a advanced control algorithm and hardware supports so that most of the operation is automatically conducted by MAST system itself except the input information that is synthesized by the measured response signals. That means the reliability of the vibration test is highly depended on the quality of the input profile. In this paper, the optimal algorithm based on the energy method is introduced to construct a best combination of candidated input PSD data could be constructed. Since the optimal algorithm renders time information, the nitration fatigue test is completely possible for any measured signals one wants. The proposed method is explained with representing acquired road signals from the candidate input PSD obtained from a proving ground.
Conductive Polymer Coated Electro-active Paper(EAPap)
Yun, Sungryul ; Ounaies Zoubeida ; Bae, Seung-Hun ; Kim, Jaehwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1077~1083
DOI : 10.5050/KSNVN.2005.15.9.1077
Electro-Active Paper (EAPap) is one of attractive electro-active polymer (EAP) materials for artificial muscles due to its many advantages such as light weight, biologically degradable, low cost, large displacement output, low actuation voltage and low power consumption. However, drawbacks of EAPap actuators include low force output and humidity dependence. To enhance the performance of EAPap, conductive polymer (PPy) and SWNT/conductive polymer (PANI) are coated on EAPap PPy as conductive polymer is coated on cellulose EAPap by means of electrochemical deposition. Two different dopants are used in PPy through conducting polymer processing. SWNTS are mixed with PANI in emeraldine base along with different dopants. The compound materials are coated on cellulose EAPap using spin coating system. The performance of PPy/EAPap and SWNT/PANI/EAPap are evaluated in terms of bending displacement, blocked force, and the effects of dopants, humidity, coaling time, voltage and frequency are investigated. Comparing with EAPap actuators, SWNT/PANI/EAPap actuators show
improvement of bending displacement and
increment of blocked force.
A Study on the Indoor Noise Limits of Apartment Houses from the Road Traffic Noise
Lee, Ju-Yeob ; Song, Min-Jeong ; Jang, Gil-Soo ; Kim, Sun-Woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1084~1091
DOI : 10.5050/KSNVN.2005.15.9.1084
The indoor noise limit for road traffic noises is needed to secure comfortable acoustical quality in apartment houses. To achieve this goal, psycho-acoustic experiments were carried out with road traffic noise sources modulated by the transmission loss characteristics of the external windows. Finally, a correlation analysis between noise rating index and subjective responses, and an analysis of satisfactory percentage of the dose-response curves varied with respondents was conducted. As a result of this study, followings are suggested. (1) On correlation between dose level and psycho-acoustical response, the initial level of negative feeling is located on
dB(A), (2) On the degree of satisfaction to road traffic noise. near
point being same dissatisfaction degree is to be assumed
dB(A) of indoor noise level presented into three vocabulary. It is suggested to be reasonable level of 40 dB(A) on the indoor noise limits for intruding road traffic noise. and it is appropriate to be the 5 dB level difference between grades. The results of this study may be used to evaluate the acoustic threshold level for road traffic noise or as a basis for specifying the desired acoustic environment of dwellings.
A Study on the Power Level Measurement and Evaluating Vocabulary of H.D. TV Sets -Focused on LCD·PDP Tv Sets-
Lee, Tai-Gang ; Park, Hyeon-Ku ; Lee, Ju-Yeob ; Lee, Jai-Cheon ; Shin, Jong-Keun ; Kim, Hye-Jin ; Kim, Sun-Woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1092~1099
DOI : 10.5050/KSNVN.2005.15.9.1092
This experimental study deals with the characteristics of LCD or PDP TV set noise, which are differ form those of CRT TV set. These characteristics are most important for establishing the effective method to reduce noise level, searching for the appropriate exposure level and evaluation method of LCD or PDP TV set noise. This study adopt two measurement method to specify the power level of LCD or PDP TV set noise in anechoic room(ISO 3741) and reverberation room(ISO 3745) . Comparing with each results of the two method, the reverberation room method is more simple in measuring and calculating the power level. And the subjective response test are carried out to select the pair of appropriate adjectives to present the characteristics of LCD or PDP TV set noise. The pair of 17 adjectives are selected from the 168 adjectives which are used in presenting the sound and noise form literature.
Identification of Failure Cause for 300 MW LP Turbine Blade through Vibration Analysis
Bae, Yong-Chae ; Lee, Hyun ; Kim, Hee-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1100~1107
DOI : 10.5050/KSNVN.2005.15.9.1100
The failure of blades frequently happened in the 300 MW LP(low pressure) turbine until now and they are maintaining the blades periodically during outage. So the blade-disk system is analysed by FEM in order to identify the main cause of failure of blade row. It is found that the stress of root`s hole is highest in comparison with other parts from the result of the steady stress analysis. Also, the two dangerous frequencies which is related to the resonance condition are found in the interference diagram. One is 1,316 Hz. The other is 2,981 Hz which is related to the 1 nozzle passing frequency. The dynamic stress analysis is performed to identify more accurate root cause for failure of blade row It is confirmed that the dynamic stress of the former is higher than one of the latter From these results, it is concluded that the former has deeply something to do with the failure of blades more than the tatter. Based on versatile investigation and deliberation, the change of blade`s grouping is determined to avoid the resonance condition with the operating speed. After the blade grouping is changed, the former frequency vanish completely but the latter is still in existence in the interference diagram. Fortunately, It is confirmed that the dynamic stress of the new blade grouping is lower than one of the old blade grouping. 2 years has passed since modification and the LP turbine is operated well without failure so far.
Robust Damage Diagnostic Method Using Short Time Fourier Transform and Beating
Lee, Ho-Cheol ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 9, 2005, Pages 1108~1117
DOI : 10.5050/KSNVN.2005.15.9.1108
A robust damage detection method using short-time Fourier transform and beating phenomena is presented as an estimating tool of the healthiness of large structures. The present technique makes use of beating phenomena that manifest themselves when two signals of similar frequencies are added or subtracted. Unlike most existing methods based on vibration signals, the present approach does not require an analytic model for target structures. Furthermore, the main advantage of the proposed method compared to the competing diagnostic method using vibration data is its robustness. The proposed method is not affected by the amplitude of exciting signals and the location of exciting points. From a measuring view point. the location of sensing point have no influence on the performance of the present method. With a view to verifying the effectiveness of this method. a series of experiments are made and the results show its possibility as a robust damage diagnostic method.