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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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Nonlinear Dynamic Characteristics of Gear Driving Systems with Periodic Meshing Stiffness Variation and Backlash
Cho, Yun-Su ; Choi, Yeon-Sun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 921~928
DOI : 10.5050/KSNVN.2002.12.12.921
Main sources of the nitration of a gear-pair system are backlash and transmission error, the difference between required and actual rotation during gear meshing. This paper presents the nonlinear dynamic characteristics of gear motions due to the existence of backlash and periodic variation of meshing stiffness, which is assumed as a one-term harmonic component. Gear motions are classified as three types with the consideration of backlash. Each response is calculated using the harmonic balance method and confirmed by numerical integration. The responses with the increase of the rotating speed show abrupt changes in its magnitude for the variation of the preload, exciting force, and damping coefficient. The result also shows that there is a chaotic motion with some specific design parameters and operating conditions In gear diving system. Consequently the design of gear driving system with low nitration and noise requires the study on the effects of nonlinear dynamic characteristics due to stiffness variation and backlash.
Vibration Analysis of Driveline with Propeller Shaft Supported by Center Bearing when the Vehicle Starts Up
Lee, Chang-Ro ; Kim, Hyo-Jun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 929~934
DOI : 10.5050/KSNVN.2002.12.12.929
This paper considers the vibration Problem of vehicle driveline which consists of two propeller shafts and the center bearing. The excessive vibration occurs at the center bearing when the vehicle starts to run. Using the kinematic constraints at the universal joint between two propeller shafts, we developed an one d.o.f model which describes the radial motion of the center bearing. We found out that the vibration occurs at the specific vehicle speed corresponding to the natural frequency of the model. Comparing the simulation results with test results we also show that the vibration at low vehicle speed is caused primarily by the feint angle and secondarily by the mis-aligned yoke flange rather than by the unbalance.
Optimization of Engine Mount Using an Enhanced Genetic Algorithm
Ahn, Young-Kong ; Kim, Young-Chan ; Yang, Bo-Suk ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 935~942
DOI : 10.5050/KSNVN.2002.12.12.935
When designing fluid mounts, design parameters can be varied in order to obtain a desired notch frequency and notch depth. The notch frequency is a function of the mount parameters and is typically selected by the designer to occur at the vibration disturbance frequency. Since the process of choosing these parameters can involve some trial and error, it seems to be a great application for obtaining optimal performance of the mount. Many combinations of parameters are possible to give us the desired notch frequency, but the question is which combination provides the lowest depth. Therefore. an automatic optimal technique is needed to optimize the performance of the fluid mount. In this study. the enhanced genetic algorithm (EGA) is applied to minimizing transmissibility of a fluid mount at the desired notch frequency, and at the notch and resonant frequencies. The EGA is modified genetic algorithm to search global and local optimal solutions of multi-modal function optimization. Furthermore. to reduce the searching time as compare to conventional genetic algorithm and Increase the precision of the solutions, the modified simplex method is combined with the algorithm. The results show that the performance of the optimized mount by using the hybrid algorithm is better than that of the conventional fluid mount.
Propagation Characteristics of the Impulse Wave Discharged from the Inclined Exit of a Pipe
Lee, D.H. ; Lee, M.H. ; Kweon, Y.H. ; Kim, H.D. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 943~949
DOI : 10.5050/KSNVN.2002.12.12.943
The propagation of the impulse wave discharged from the Inclined exit of a pipe is investigated through shock tube experiment and numerical computations. The pressure histories and directivities of the impulse wave propagating outside from the exit of pipe with several different configurations are analyzed for the range of the incident shock wave Mach number between 1.1 and 1.4. In the shock tube experiments, the impulse waves are visualized by a Schlieren optical system for the purpose of validation of computational work. Computations using the two-dimensional. unsteady, compressible, Euler equations are carried out to represent the experimented impulse waves. Computed Schlieren images predict the experimented impulse waves with a good accuracy. The results obtained show that for the radial direction the peak pressure of the impulse wave discharged depends upon the Inclined angle of the exit of the pipe. but for the axial direction it is almost constant regardless of the inclined angle of the pipe exit.
Active Control of Sound Fields from Vibrating Plates Using Piezoelectric and Viscoelastic Material
Kang, Young-Kyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 950~955
DOI : 10.5050/KSNVN.2002.12.12.950
The coupled finite/boundary element method is used in numerical analysis for acoustic radiation from the vibration of rectangular composite plate which is simply supported. This analysis is validated using the Wallace equation for an isotropic plate. Active control of sound fields has been tarried out using 3 pairs of piezoelectric sensor/actuator and a pair of viscoelastic material by Passive constrained layer damping treatment. The results show that the optimal placement of piezoelectric sensor/actuator and VE patch is required to control the sound fields from a vibrating composite plate.
Evaluation of Tension Force of Stay Cables Using Vibration Method
Kim, Nam-Sik ; Jeong, Woon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 956~963
DOI : 10.5050/KSNVN.2002.12.12.956
In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed according to rapidly upgrade their related technologies. Generally stay cables as a critical member need to be rearranged for being satisfied with design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted on existing stay cables. In this study, cable vibration tests were tarried out to evaluate the cable tension forces comparing with theoretical and practical formulas. Using the measured frequencies obtained from free vibration and Impulsive tests, an accuracy of the estimated tension forces is confirmed according to use the first single mode only or higher multiple modes.
Vibration Characteristics of Laminated Composite Beams with Passive Constrained Layer Damping
Kang, Young-Kyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 964~969
DOI : 10.5050/KSNVN.2002.12.12.964
The flexural vibration of laminated composite beams with passive constrained layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of Iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations.
Free Vibrations of Arches in Cartesian Coordinates
Lee, Byoung-Koo ; Lee, Yong-Soo ; Kim, Il-Jung ; Choi, Kou-Moon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 970~978
DOI : 10.5050/KSNVN.2002.12.12.970
The differential equations governing free vibrations of the elastic arches with unsymmetric axis are derived in Cartesian coordinates rather than in polar coordinates. in which the effect of rotatory inertia is included. Frequencies and mode shapes are computed numerically for parabolic arches with both clamped ends and both hinged ends. Comparisons of natural frequencies between this study and SAP 2000 are made to validate theories and numerical methods developed herein. The convergent efficiency is highly improved under the newly derived differential equations in Cartesian coordinates. The lowest four natural frequency parameters are reported, with and without the rotatory inertia, as functions of three non-dimensional system parameters the rise to chord length ratio. the span length to chord length ratio, and the slenderness ratio. Also typical mode shapes of vibrating arches are presented.
Dynamic Stability of a Vertical Cantilevered Pipe Conveying Fluid with Additional Spring Supports
Ryu, Bong-Jo ; Jung, Seoung-Ho ; Lee, Jong-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 979~985
DOI : 10.5050/KSNVN.2002.12.12.979
The paper presents the dynamic stability of a vertical cantilevered pipe conveying fluid and haying translational linear spring supports. Real pipe systems may have some elastic hanger supports or other mechanical attached parts. which can be regarded as attached spring supports. Governing equations are derived by energy expressions, and numerical technique using Galerkin`s method is applied to the equations of small motion of the pipe. Effects of spring supports on the dynamic stability of a vortical cantilevered pipe conveying fluid are fully investigated for various locations and spring constants of elastic supports.
Dynamic Response Analysis of AGT Vehicle Considering Surface Roughness of Railway
Song, Jae-Pil ; Kim, Chul-Woo ; Kim, Ki-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 986~993
DOI : 10.5050/KSNVN.2002.12.12.986
The equations of motion for an automated guide-way transit(AGT) system running on a path with roughness have been derived to investigate dynamic responses and wheel loads of moving vehicles of the AGT system. A vehicle of the AGT system is idealized as three-dimensional model with 11 degree-of-freedom. The computer program is developed to solve the dynamic equations, and anlatical results are verified by comparing the results with experimental oness. Parametric studies are carried out to investigate the dynamic responses of an AGT vehicle according to vehicle speeds, surface roughness, damping and stiffness of suspension systems. The parametric study demonstrates that amplitudes of dynamic responses and the wheel loads have a tendency to increase according to travel speeds, the stiffness of suspension system and surface roughness. On the other hand. those amplitudes tend to decrease according to increase of damping of the suspension system.
Vibration Localization due to Mistuned Coupling Effects Among Repeated Structures
Kang, Min-Kyoo ; Yoo, Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 994~1000
DOI : 10.5050/KSNVN.2002.12.12.994
In periodically repeated cyclic structures, small property irregularity of their substructures often causes significant difference in their dynamic responses. which results in unpredicted premature failures. The small irregularity and the resulting phenomenon are called the mistuning and the vibration localization. respectively. In this paper, the vibration localization phenomena due to mistuned coupling effects are investigated. To effectively achieve the objective, a simple coupled multi-pendulum system Is employed. The results show that if there exists some coupling stiffness irregularity, vibration localization may occur and becomes more predominant as the number of substructures increases.
Dynamics of a Micro Three-axis Ring Gyroscope
Kim, Chang-Boo ; Choi, Sang-Hyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 12, issue 12, 2002, Pages 1001~1009
DOI : 10.5050/KSNVN.2002.12.12.1001
In this paper, we analyse and present mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure angular velocities about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the rotation of the gyroscope main body. The equations of motion, the response to angular velocities, and the relationships between the natural modes of vibration are derived and compared with the previous studies for the design of a micro three-axis ring gyroscope.