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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 14, Issue 12 - Dec 2004
Volume 14, Issue 11 - Nov 2004
Volume 14, Issue 10 - Oct 2004
Volume 14, Issue 8 - Aug 2004
Volume 14, Issue 7 - Jul 2004
Volume 14, Issue 6 - Jun 2004
Volume 14, Issue 5 - May 2004
Volume 14, Issue 4 - Apr 2004
Volume 14, Issue 9 - Mar 2004
Volume 14, Issue 3 - Mar 2004
Volume 14, Issue 2 - Feb 2004
Volume 14, Issue 1 - Jan 2004
Selecting the target year
Dynamic Characteristics of Journal Bearings Considering Bearing Span
Yoon, Jinwook ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 779~784
DOI : 10.5050/KSNVN.2004.14.9.779
This paper numerically analyzes the dynamic characteristics of a spindle system supported by two identical journal bearingsconsidering bearing span that has dynamic load due to its mass unbalance. The Reynolds equation is transformed to solve a herringbone grooved journal bearing. The Reynolds equations are solved using FEM in order to calculate the pressure distribution in a fluid film. Reaction forces and friction torque are obtained by integrating the pressure and shear stress along the fluid film, respectively. Dynamic behaviors, such as whirl radius or angular displacement of a rotor, are determined by solving its nonlinear equations of motion with the Runge-Kutta method. This research shows that the same bearing spans of upper and lower journal bearings produce the minimum runout and friction torque of a spindle system.
A Design Study of Aerodynamic Noise Reduction in Centrifugal Compressor Part I : Performance Analysis and Noise Prediction
Sun, Hyosung ; Lee, Soogab ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 785~791
DOI : 10.5050/KSNVN.2004.14.9.785
The objective of this research is to suggest anoise prediction method for a centrifugal compressor. It is focused on the Blade Passing Frequency component which is regarded as the main part of the rotating impeller noise. Navier-Stokes solver is used to simulate the flow-field of the centrifugal compressor, and the time-dependent pressure data are calculated to perform the near-field noise prediction by using Ffowcs Williams - Hawkings formulation. Indirect Boundary Element Method is applied to consider the noise propagation effect. Pressure fluctuations of the inlet and the outlet in the centrifugal compressor impeller are presented and the sound pressure level prediction results are compared with the experimental data.
Analysis of NRRO Caused by Ball Bearing in a HDD Spindle System at Elevated Temperature
Kim, D.K. ; Jang, G.H. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 792~800
DOI : 10.5050/KSNVN.2004.14.9.792
This research investigates the non-repeatable runout (NRRO) of a HDD spindle system at elevated temperature by analyzing the characteristics of a ball bearing and the natural vibration characteristics of a HDD spindle system due to the effect of elevated temperature. It shows that the elevated temperature results in the increase of the contact angle and the decrease of the deformation of the ball bearing in a HDD spindle system. The variation of bearing frequencies, which are dependent on the cosine function of contact angle, is almost negligible at elevated temperature. However, the decrease of bearing deformation at elevated temperature reduces the stiffness of the ball bearing and the natural frequencies of a HDD spindle system consequently. The latter has a significant effect on the amplitude and the frequency distribution of NRRO at elevated temperature.
Model Updating Using the Closed-loop Natural Frequency
Jung Hunsang ; Park Youngjin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 801~810
DOI : 10.5050/KSNVN.2004.14.9.801
Parameter modification of a linear finite element model(FEM) based on modal sensitivity matrix is usually performed through an effort to match FEM modal data to experimental ones. However, there are cases where this method can`t be applied successfully; lack of reliable modal data and ill-conditioning of the modal sensitivity matrix constitute such cases. In this research, a novel concept of introducing feedback loops to the conventional modal test setup is proposed. This method uses closed-loop natural frequency data for parameter modification to overcome the problems associated with the conventional method based on modal sensitivity matrix. We proposed the whole procedure of parameter modification using the closed-loop natural frequency data including the modal sensitivity modification and controller design method. Proposed controller design method is efficient in changing modes. Numerical simulation of parameter estimation based on time-domain input/output data is provided to demonstrate the estimation performance of the proposed method.
Evaluation of Floor Impact Sound Performance according to the Reduction Methods
Choi Gyoung-Seok ; Choi Hyun-jung ; Yang Kwan-Seop ; Kim Kyoung-Woo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 811~818
DOI : 10.5050/KSNVN.2004.14.9.811
Impact sounds, such as those created by footsteps, the dropping of an object or the moving of furniture, can be a source of great annoyance in residential buildings. The character and level of impact noise generated depends on the object striking the floor, on the basic structure of the floor, and on the floor covering. This study base on the evaluate of isolation performance of impact sound according to the impact noise reduction methods. Reduction methods consist of four ways. First way is increase thickness of bare floor and other ways are using the soft coverings on the floor and ceiling assembles. Last way is make floating floor with shock absorbing materials.
Optimal Placement of Strain Gauge for Vibration Measurement for Fan Blade
Choi ByeongKeun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 819~826
DOI : 10.5050/KSNVN.2004.14.9.819
A multi-step optimum strategy for the selection of the locations and directions of strain gauges is proposed in this paper to capture at best the modal response of blade in a series of modes on fan blades. It is consist of three steps including two pass reduction step, genetic algorithm and fine optimization to find the locations-directions of strain gauges. The optimization is based upon the maximum signal-to-noise ratio(SNR) of measured strain values with respect to the inherent system measurement noise, the mispositioning of the gauge in location and gauge failure. Optimal gauge positions for a fan blade is analyzed to prove the effectiveness of the multi-step optimum methodology and to investigate the effects of the considering parameters such as the mispositioning level, the probability of gauge failure, and the number of gauges on the optimal strain gauge position.
Design of a Robust Track-following Controller with Multiple Constraints
Jin Kyoun Bog ; Kim Jin-Soo ; Lee Moon-Noh ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 827~836
DOI : 10.5050/KSNVN.2004.14.9.827
In this paper, we design a robust multi-objective track-following controller that satisfies transient response specifications and diminishes the influence of sinusoidal disturbance. To this end, a robust control problem with the multiple constraints is considered. We show that a sufficient condition satisfying the robust control problem can be expressed by linear matrix inequalities. Finally, the robust track-following controller can be designed by solving an LMI optimization problem. The effectiveness of the proposed controller design method is verified though experiments.
A Study on the Variable Damper System for Vehicle Driveline
Park Dong-Hoon ; Choi Myung-Jin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 837~845
DOI : 10.5050/KSNVN.2004.14.9.837
A variable friction damper for vehicle driveline has been proposed. This new torsional damper system uses a solenoid as an actuator to vary friction force of the damper. To verify the idea of using a solenoid in a variable damper system, the test fixture and the dampers are made and tested. Also, to find out the range of damper friction forces that influence the vehicle driveline vibration, a mathematical model of the driveline had been developed and simulated. Test and simulation results show that, within electric current used in the vehicle electric system, the solenoid can develop enough friction force that will surpass resonance in the driveline of 1.5 L Gasoline engine vehicle during acceleration.
Dynamic Analysis of Micro Cantilever Beams Undertaking Electrostatic Forces
Jung Kang-Sik ; Moon Seung-Jae ; Yoo Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 846~851
DOI : 10.5050/KSNVN.2004.14.9.846
Static and dynamic responses of micro cantilever beam structures undertaking electrostatic forces are obtained employing Galerkin`s method based on Euler beam theory. Variations of static and dynamic responses as well as resonant frequencies are estimated for several sets of beam properties and applied voltages. It is shown that the applied voltage influences the deflection and the modal characteristics significantly. Such information can be usefully employed for the design of MEMS structures.
Comparison of Test Methods for Vibration Damping Properties
Shin Su Hyun ; Lee Yong Bong ; Jung Sung Soo ; Lee Doo Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 852~860
DOI : 10.5050/KSNVN.2004.14.9.852
There are many standard methods for measuring vibration damping properties of the beam type material. Among them, three standards ASTM E 756, ISO 6721 and JIS G 0602, are compared. Loss factor and Young`s modulus of the steel beam are evaluated by using five different methods and their results are compared. Logarithmic decay method and half-power bandwidth method are used to calculate the loss factor. It was observed that Young’s modulus is agree well, but loss factors are different from test to test. So the same test method must be applied to measure damping properties.
Study on Noise Reduction of DLP Front Home Theater Projector
Jang Dong Seob ; Park Chul Min ; Park Dae Kyong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 861~867
DOI : 10.5050/KSNVN.2004.14.9.861
For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.
Dynamic Characteristics of Linear Motion Supported by Rolling Ball Bearings
Choi Jae Seok ; Yi Yong-sub ; Kim Yoon Young ; Lee Dong Jin ; Lee Sung Jin ; Yoo Jeonghoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 868~876
DOI : 10.5050/KSNVN.2004.14.9.868
The linear motion(LM) guide using ball bearing has many advantages compared with conventional sliding guides. Therefore, LM guide using ball bearing has been widely used to increase the accuracy of the position of a system. This research investigates dynamic characteristics of LM guide through mainly linear analyses. Linear analysis is accomplished by Lagrange equation and the finite element method. And another trial that performs nonlinear analysis about one mode(bouncing mode) of LM guide from Hertzian contact theory is accomplished in the latter half of this research. Through nonlinear analysis we could observe the softening characteristic due to the Hertzian contact nonlinearity.
Impulsive Source Localization in Noise
Kim Yang-Hann ; Choi Young-Chul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 877~883
DOI : 10.5050/KSNVN.2004.14.9.877
This paper addresses the way in which we can find where impulsive noise sources are. Specifically, we have an interest in the case that the signal is embedded in noise. We propose a signal processing method that can identify impulsive sources` location. The method is robust with respect to spatially distributed noise. This has been achieved by the modified beamforming method with regard to cepstrum domain is used. It is noteworthy that the cepstrum has the ability to detect periodic pulse signal in noise. Numerical simulation and experiments are performed to verify the method. Results show that the proposed technique is quite powerful for localizing the faults in noisy environments. The method also required less microphones than conventional beamforming method.
Development of an Index for the Evaluation of Intake Booming Noise of a Passenger Car
Park Y. W. ; Chai J. B. ; Jang H. K. ; Lee J. K. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 884~890
DOI : 10.5050/KSNVN.2004.14.9.884
In this paper, an index for the evaluation of vehicle intake booming noise is developed through a correlation analysis of objective measurement data and subjective evaluation data. First, intake orifice noise is measured at the wide-open test condition. And then, acoustic transfer function between intake orifice noise and interior noise at the steady state condition is estimated. Simultaneously, subjective evaluation was carried out with a ten-scale score by 8 engineers. Next, the correlation analysis between the psycho-acoustic parameters derived from the measured data and the subjective evaluation is performed. The most critical factor was determined and the corresponding index for the intake booming noise is obtained from the multiple factor regression method. At last, the effectiveness of the proposed index is validated.
Analysis the Performance of Asymmetric Optical Pick-up Actuator with PCB type Coil
Shin KyungSik ; Hong Goo ; Kim JeenGi ; Jun YoungJin ; Lee DooHwan ; Bae WonCheol ; Lee JaeKul ; Im JangYoeng ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 891~896
DOI : 10.5050/KSNVN.2004.14.9.891
`Coil` occupies very much important position in delivering driving force of optical pick-up actuators. Up to now the main stream has been a winding coil type actuator, but actuators using FP-Coil(fine pattern coil) have been considered for the more compacted and simple manufacturing process and have variously spreaded the application fields by product. We have tried to design actuators using PCB-Coil(printed circuit board coil) which has benefits in terms of price and manufacturing process. Especially this research has two main things to reduce the vibration of sub-resonance and to assure the DC sensitivity among the performances of asymmetric optical pick-up actuator with PCB-Coil.
Estimation of the Vibration Endurance Characteristics of Air Cleaner Insulators for Vehicles
Kim Jung Heon ; Kim Seockhyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 897~902
DOI : 10.5050/KSNVN.2004.14.9.897
In this paper, a vibration endurance test is performed on rubber insulators used for vehicle air cleaners. Based on the test results, the endurance characteristics depending on the type and the material of the insulators are estimated. The frequency response characteristics of the air cleaner system including the insulator are investigated to identify the cause of wear and failure of the insulator. New insulator models with improved endurance characteristics are proposed and tested. Test results show that the vibration endurance property of the insulator is strongly dependent on the frequency response characteristics of the air cleaner system as well as the deformed shape of the insulator.
A Study on Resonance and Interference of a Cooling Fan Assembly by Using FEM
Seo Jong-Hwi ; Song Ha-Jong ; Park Tae-Won ; Kim Joo-Yong ; Jung Il-Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 903~909
DOI : 10.5050/KSNVN.2004.14.9.903
A CFA(cooling fan assembly) is composed of a fan, motor and shroud, which is at the back of the automotive radiator. By forcing the wind to pass, the CFA controls the cooling performance of the radiator. The noise and vibration of the CFA may be primarily due to the resonance between the CFA and engine. The Interference among the fan, shroud and radiator by deformation is considered when the CFA is designed. In this paper, in order to analyze the structural vibration of the CFA for automobiles, a finite element model of the CFA is established by using a commercial FEM code. After the finite element modeling, the natural frequencies and the mode shapes are obtained from the FE analysis. The natural frequencies are obtained from the vibration test as well. Then, the results of the vibration test are compared with those of the FE analysis. The natural frequencies obtained by experiment have a great similarity to the results from FE model. We have confirmed the validity of the FE model and verify the structural safety for the resonance. The stress and displacements are obtained from FE analysis. We have confirmed the safety for the interference and failure.
Vibration Analysis of an Axially Moving Membrane with In-plane/Out-of-plane Deformations
Shin Changho ; Chung Jintai ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 14, issue 9, 2004, Pages 910~918
DOI : 10.5050/KSNVN.2004.14.9.910
The vibration analysis of an axially moving membrane are investigated when the membrane has the two sets of in-plane boundary conditions, which are free and fixed constraints in the lateral direction. Since the in-plane stiffness is much higher than the out-of-plane stiffness, it is assumed during deriving the equations of motion that the in-plane motion is in a steady state. Under this assumption, the equation of out-of-plane motion is derived, which is a linear partial differential equation influenced by the in-plane stress distributions. After discretizing the equation by using the Galerkin method, the natural frequencies and mode shapes are computed. In particular, we put a focus on analyzing the effects of the in-plane boundary conditions on the natural frequencies and mode shapes of the moving membrane.