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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 12, Issue 12 - Dec 2002
Volume 12, Issue 11 - Nov 2002
Volume 12, Issue 10 - Oct 2002
Volume 12, Issue 9 - Sep 2002
Volume 12, Issue 8 - Aug 2002
Volume 12, Issue 7 - Jul 2002
Volume 12, Issue 6 - Jun 2002
Volume 12, Issue 5 - May 2002
Volume 12, Issue 4 - Apr 2002
Volume 12, Issue 3 - Mar 2002
Volume 12, Issue 2 - Feb 2002
Volume 12, Issue 1 - Jan 2002
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Experimental Analysis of Axial Vibration in Slim-type Optical Disc Drive
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 833~839
DOI : 10.5050/KSNVN.2002.12.11.833
As the demand for slim laptops requires low-height optical disc drives, vibration problems of optical disc drives are of great concern. Additionally, with the decrease of a track width and a depth of focus in high density drives, studies on vibration resonance between mechanical parts become more important. From the vibration point of view, the performance of optical disc drives is closely related with the relative displacement between a disc and an objective lens which is controlled by servo mechanism. In other words, to read and write data properly, the relative displacement between an optical disc and an objective lens should be within a certain limit. The relative displacement is dependent on not only an anti-vibration mechanism design but also servo control capability. Good servo controls can make compensation for poor mechanisms, and vice versa. In a usual development process, robustness of the anti-vibration mechanism is always verified with the servo control of an objective lens. Engineers partially modify servo gain margin in case of a data reading error. This modification cannot correct the data reading error occasionally and the mechanism should be redesigned more robustly. Therefore it is necessary to verify a mechanism with respect to the possible servo gain plot. In this study we propose the experimental verification method for anti-vibration mechanism with respect to the existing servo gain plot. Thismethod verifies axial vibration characteristics of optical disc drives on the basis of transmissibility. Using this method, we verified our mechanism and modified the mechanism for better anti-vibration characteristics.
The Influence of Moving Masses on Natural Frequency of Cantilever Pipe Conveying Fluid
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 840~846
DOI : 10.5050/KSNVN.2002.12.11.840
The vibrational system of this study is consisted of a cantilever pipe conveying fluid, the moving masses upon it and an attached tip mass. The equation of motion is derived by using Lagrange equation. The influences of the velocity and the number of moving masses and the velocities of fluid flow in the pipe have been studied on the natural frequency of a cantilever pipe by numerical method. As the size and number of a moving mass increases, the natural frequency of cantilever pipe conveying fluid is decreased. When the first a moving mass Is located at the end of cantilever pipe, the increasing of the distance of moving masses make the natural frequency increase at first and third mode, but the frequency of second mode is decreased. The variation of natural frequency of the system is decreased due to increase of the number of a moving mass. The number and distance of moving masses effect more on the frequency of higher mode of vibration
Transient Vibration Analysis of a Rotary Compressor Considering the Coupled Effects of Motor
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 847~855
DOI : 10.5050/KSNVN.2002.12.11.847
A rotary compressors are used most widely In air-conditioning systems. Noise and vibration of a rotary compressor is an important problems during turning on and off as well as during operating. To estimate the vibration occurring during turning on and off, vibration analysis of a motor-compressor coupled system is required. In this paper, through modeling the motor and solving the forces from the equations of motion of the moving parts, the analysis of vibration of the compressor taking into consideration of the effects of motor and moving parts was performed. The accelerations of accumulator during turning on. turning off and operation are simulated. And simulated accelerations are compared with those of experimental data.
Seismic Qualification of the Main Control Board for Nuclear Power Plant
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 856~863
DOI : 10.5050/KSNVN.2002.12.11.856
Seismic qualification of the main control board(MCB) for the nuclear power plant Ulchin 5 and 6 has been performed with the guideline of ASME Section III and IEEE 344 code. As the size and weight of the MCB are too large and heavy to excite using the excitation table, finite element analysis is used in order to investigate the dynamic behaviors and structural integrity of the MCB. As the fundamental frequencies of the equipment are found to be less than 33 Hz, which is the upper frequency limit for the dynamic analysis, response spectrum analysis using ANSYS is performed in order to combine the modal stresses within the frequency limit. In order to confirm the electrical stability of the major components of the MCB. modal analysis theory has been adopted to derive the required response spectra at the component locations. As the all combined stresses obtained from the above procedures are less than the allowable stresses and no mechanical or electrical failures are found from the seismic testing, the authors can confirm the safety of the nuclear equipment MCB under the given seismic loading conditions.
Planform Curvature Effects on the Stability of Coupled Flow/Structure Vibration
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 864~872
DOI : 10.5050/KSNVN.2002.12.11.864
In this study, the effect of planform curvature on the stability of coupled flow/structure vibration is examined in transonic and supersonic flow regions. The aeroelastic analysis for the frequency and time domain is performed to obtain the flutter solution. The doublet lattice method(DLM) in subsonic flow is used to calculate unsteady aerodynamics in the frequency domain. For all speed range, the time domain nonlinear unsteady transonic small disturbance code has been incorporated into the coupled-time integration aeroelastic analysis (CTIA). Two curved wings with experimental data have been considered in this paper MSC/NASTRAN is used for natural free vibration analyses of wing models. Predicted flutter dynamic pressures and frequencies are compared with experimental data in subsonic and transonic flow regions.
Nonlinear Characteristics of Low-speed Flow Induced Vibration for the Safety Design of Micro Air Vehicle
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 873~881
DOI : 10.5050/KSNVN.2002.12.11.873
The fluid induced vibration (FIV) phenomena of an equivalent airfoil system of MAV have been investigated in low Reynolds number flow region. Unsteady flows with viscosity are computed using two-dimensional incompressible Navier-Stokes equations. The present fluid/structure interaction analysis is based on one of the most accurate computational approach with computational fluid dynamics (CFD) and computational structural dynamics (CSD) techniques. The highly nonlinear fluid/structure interaction phenomena due to severe flow separations have been analyzed for the low Reynolds region that has a dominancy of flow viscosity. The effects of Reynolds number and initial angle of attack on the fluid/structure coupled vibration instability are shown and the qualitative trend of FIV phenomenon is investigated.
Investigation on Vibration Control of Squeeze Mode ER Mount Subjected to 200 kg of Static Load
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 882~889
DOI : 10.5050/KSNVN.2002.12.11.882
This paper presents vibration control performance of a squeeze mode ER mount for high static load. After experimentally investigating the field-dependent damping force under the squeeze mode motion, a squeeze mode ER mount which can support 200 kg of static load is designed and manufactured. Displacement transmissibility of the proposed ER mount is experimentally evaluated in frequency domain with respect to the intensity of the electric field, and a sky-hook control algorithm is designed to attenuate unwanted vibration. Vibration isolation capabilities of the flow mode ER mount and rubber mount are compared to those of the proposed squeeze mode ER mount.
Dynamic Stability of a Drum-brake Shoe Under a Pulsating Frictional Force
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 890~896
DOI : 10.5050/KSNVN.2002.12.11.890
This paper deals with the dynamic stability of a brake shoe under pulsating frictional forces. A lining part of brake systems is assumed as a distributed spring, and the supported elements of a shoe are assumed as translational springs for a constant distributed frictional force and a pulsating frictional force. Governing equations are derived by the use of the extended Hamilton's principle, and numerical results are calculated by finite element method. The critical distributed frictional force and instability regions were investigated for the change of distributed spring constants and translational spring constants.
Examination of the Periodic High Vibration by the Accumulated Carbide at Oil Deflector of a Steam Turbine for Power Plant
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 897~903
DOI : 10.5050/KSNVN.2002.12.11.897
The periodic high vibration has been occurred one or two times a day for a 500 MW large steam turbine during 5 months. This abnormal vibration was caused by the rubbing between the rotor and the carbide accumulated on the seal tooth of oil deflector. It was found that the accumulated carbide was insulation material installed on the HIP casing from the examination of the chemical composition. Also, this paper presents the mechanism of the periodic high vibration and the proper method to eliminate this vibration problem. This result would be good practice to find the solution of similar high vibration in the steam turbines for power plant as well as industrial rotating machineries.
Dynamic Analysis of the Small Reciprocating Compressors Considering Viscous Frictional Force of a Piston
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 11, 2002, Pages 904~913
DOI : 10.5050/KSNVN.2002.12.11.904
In this study, a dynamic analysis of the reciprocating compression mechanism considering viscous friction force of a piston used in small refrigeration compressors is performed. The length of cylinder in this class of compressors is shortening to diminish the frictional losses of the piston-cylinder system. So, the contacting length between piston and cylinder liner is in variable with the rotating crank angle around the BDC of the reciprocating piston. In the problem formulation of the compression mechanism dynamics, the change in bearing length of the piston and all corresponding viscous forces and moments are considered in order to determine the trajectories of piston and crankshaft. The piston orbits for viscous friction model and Coulomb friction model were used to compare the effect of the friction forces of piston on the dynamic trajectories of piston. To investigate the effect of friction force acting on the piston for the dynamic characteristics of crankshaft, comparison of the crankshaft loci is given in both viscous model and Coulomb model. Results show that the viscous friction force of piston must be considered in calculating for the accurate dynamic characteristics of the reciprocating compression mechanism.