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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 13, Issue 12 - Dec 2003
Volume 13, Issue 11 - Nov 2003
Volume 13, Issue 10 - Oct 2003
Volume 13, Issue 9 - Sep 2003
Volume 13, Issue 8 - Aug 2003
Volume 13, Issue 7 - Jul 2003
Volume 13, Issue 6 - Jun 2003
Volume 13, Issue 5 - May 2003
Volume 13, Issue 4 - Apr 2003
Volume 13, Issue 3 - Mar 2003
Volume 13, Issue 2 - Feb 2003
Volume 13, Issue 1 - Jan 2003
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Convergence of the Filtered-x Least Mean Square Adaptive Algorithm for Active Noise Control of a Multiple Sinusoids
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 239~246
DOI : 10.5050/KSNVN.2003.13.4.239
Application of the filtered-x Least Mean Square(LMS) adaptive filter to active noise control requires to estimate the transfer characteristics between the output and the error signal of the adaptive controller. In this paper, we derive the filtered-x adaptive noise control algorithm and analyze its convergence behavior when the acoustic noise consists of multiple sinusoids. The results of the convergence analysis of the filtered-x LMS algorithm indicate that the effects of the parameter estimation inaccuracy on the convergence behavior of the algorithm are characterized by two distinct components Phase estimation error and estimated gain. In particular, the convergence is shown to be strongly affected by the accuracy of the phase response estimate. Simulation results are presented to support the theoretical convergence analysis.
Stability Analysis of a Herringbone Grooved Journal Bearing with Rotating Grooves
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 247~257
DOI : 10.5050/KSNVN.2003.13.4.247
This paper presents an analytical method to Investigate the stability of a hydrodynamic journal bearing with rotating herringbone grooves. The dynamic coefficients of the hydrodynamic Journal bearing are calculated using the FEM and the perturbation method. The linear equations of motion can be represented as a parametrically excited system because the dynamic coefficients have time-varying components due to the rotating grooves, even in the steady state. Their solution can be assumed as a Fourier series expansion so that the equations of motion can be rewritten as simultaneous algebraic equations with respect to the Fourier coefficients. Then, stability can be determined by solving Hill's infinite determinant of these algebraic equations. The validity of this research is proved by the comparison of the stability chart with the time response of the whirl radius obtained from the equations of motion. This research shows that the instability of the hydrodynamic journal bearing with rotating herringbone grooves increases with increasing eccentricity and with decreasing groove number, which play the major roles in increasing the average and variation of stiffness coefficients, respectively. It also shows that a high rotational speed is another source of instability by increasing the stiffness coefficients without changing the damping coefficients.
A Study on the Noise Reduction of the Engine Cooing Fan of a Express Bus by Modification of Design Parameters
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 258~265
DOI : 10.5050/KSNVN.2003.13.4.258
This paper suggests the noise reduction method of the engine cooling fan. The fan noise contribution to the OASPL of engine room was estimated and the noise source was identified for the rotating fan by sound intensity method. And the program for Predicting the noise spectrum of axial flow fan was also developed. The radiated acoustic pressure is expressed in terms of discrete frequency noise Peaks at BPF and its harmonics and the line spectrum at the broad band by the proposed noise generation mechanisms. In this Paper, it Is shown that the comparison of the measured and calculated noise spectra of fan validates the noise predicting program. And this paper presents the characteristics of the fan noise in order to modify the design parameters. Accordingly, the design parameters were determined for the noise reduction of the fan.
Analysis and Small Scale Model Expriment on the Vertical Vibration of the KT-23 Type Passenger Vehicle
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 266~273
DOI : 10.5050/KSNVN.2003.13.4.266
The purpose of this study is to obtain the effects of the parameters of the suspension system in railway rolling-stock for KT-23 type Passenger vehicle. According to the analysis and the small scale model car test. optimal condition was obtained for the stiffness ratio of secondary spring to primary spring of the suspension system and the mass ratio of the bogie frame to the car body. The analysis of the study shows that if the car body mass is increased or secondary stiffness Is lowered, the vertical vibration level is reduced and the passenger comfort can be improved. Especially, strong peaks are occurred in the frequencies corresponding to the rotational speed of driving axle and vehicle wheel. Hence, in order to obtain the dynamic characteristics through the small scale model car, the driving method of the vehicle on the test bench, rotational characteristics of the wheel and the natural modes of vehicle should be investigated and be modified.
Development of a Low Frequency Vibration Shaker Using Force Frequency Shifting
;L. L. Koss;;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 274~280
DOI : 10.5050/KSNVN.2003.13.4.274
If a sinusoidal excitation force moves back and forth along a structure with a certain frequency, the structure will be excited with the difference frequency of these two frequencies. A low frequency vibration shaker has been developed using this force frequency shifting without actually moving a shaker The shaker consists of an ordinary eccentric mass shaker, a plate, constant springs, and time varying dampers. The dampers are turned on and off in a sequential manner to simulate a traveling slide of an excitation force. The operation of the shaker is simulated by solving the equations of motion of the shaker. Characteristics of the shaker have been found and they can be utilized to design efficient low frequency shakers.
Free Vibrations of Thick Plates with Concentrated Masses on In-homogeneous Pasternak Foundation
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 281~289
DOI : 10.5050/KSNVN.2003.13.4.281
Recently, as high-rise buildings increase steeply, sub-structures of them are often supported on in-homogeneous foundation. And there are many machines in sub-structures of buildings, and slabs of sub-structures are affected by vibration which they make. This paper deals with vibration of plates with concentrated masses on in-homogeneous foundation. Machines on plates are considered as concentrated masses. In-homogeneous foundation is considered as assigning
to Winkler foundation parameters of central region and side region of plate respectively, and foundation is idealized to use Pasternak foundation model which considered both of Winkler foundation parameter and shear foundation parameter. In this paper, applying Winkler foundation parameters which
and shear foundation parameter which are 10, 20 respectively, first natural frequencies of thick plates with concentrated masses on in-homogeneous foundations are calculated.
Dynamic Modeling and Analysis of General Rotor Systems with Open Cracks
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 290~299
DOI : 10.5050/KSNVN.2003.13.4.290
This paper presents an efficient modeling and dynamic analysis method for open cracked rotor bearing systems. An equivalent bending spring model is introduced to represent the structural weakening effect in the presence of cracks. The proposed modeling method is validated through a series of simulations and experiments. First, the proposed method Is rigorously compared with a commercial finite element code. Then, an experiment is performed to validate the proposed modeling method. Finally, a numerical example is introduced to demonstrate the possible application of the proposed method in the crack diagnosis for rotor systems.
Multi-mode Noise Reduction of Smart Panels Using Piezoelectric Shunt Damping
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 300~307
DOI : 10.5050/KSNVN.2003.13.4.300
This paper presents the multi-mode noise reduction of smart panels of which passive piezoelectric shunt damping is introduced. For the piezoelectric shunt damping, a passive shunt circuit composed of inductors and a load resistor is connected to the piezoelectric patch mounted on the panel structure. An electrical impedance model is introduced for the system based on the measured electrical impedance, and the criteria for maximum energy dissipation at the shunt circuit is used to find the optimal shunt parameters. For multi-mode shunt damping, the shunt circuit is modified by the introduction of a block circuit. Also the optimal location of the piezoelectric patch is studied by finite element analysis in order to cause the maximum admittance from the patch for each mode of the structure. An acoustic test is performed for the panels and a remarkable noise reduction is obtained in multiple modes of the panel structure.
A Study on Design and Characteristics of Linear Magnetostrictive Actuator Using Terfenol-D
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 308~316
DOI : 10.5050/KSNVN.2003.13.4.308
Terfenol-D is one of magnetostrictive materials which have the property of converting the energy in magnetic fields into mechanical movement and vice versa. We designed and fabricated a linear magnetostrictive actuator using Terfenol-D. It has 25 mm diameter and 100 mm long. To grasp the characteristics of it, a series of tests were performed in the range of 50 Hz below. Induced-strain actuation displacements of the actuator measured by test and predicted by magnetic analysis agreed well. And blocked forces according to the input currents were estimated from the testing results. Modelling method representing the exerting force of a linear magnetostrictive actuator was confirmed through some testing results.
Nonlinear Torsional Oscillations of a System incorporating a Hooke's Joint : 2-DOF Model
Transactions of the Korean Society for Noise and Vibration Engineering, volume 13, issue 4, 2003, Pages 317~322
DOI : 10.5050/KSNVN.2003.13.4.317
Torsional oscillations of a system incorporating a Hooke's joint are investigated by adopting a nonlinear 2-degree-of-freedom model. Linear and Van der Pol transformations are applied to obtain the equations of motion to which the method of averaging can be readily applied. Various subharmonic and combination resonances are identified with the conditions of their occurrences. Applying the method of averaging leads to the reduced amplitude- and phase-equations of motion, of which constant and periodic solutions are obtained numerically. The periodic solution which emerges from Hopf bifurcation point experiences period doubling bifurcation leading to infinite solution rather than chaotic solution.