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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 25, Issue 12 - Dec 2015
Volume 25, Issue 11 - Nov 2015
Volume 25, Issue 10 - Oct 2015
Volume 25, Issue 9 - Sep 2015
Volume 25, Issue 8 - Aug 2015
Volume 25, Issue 7 - Jul 2015
Volume 25, Issue 6 - Jun 2015
Volume 25, Issue 5 - May 2015
Volume 25, Issue 4 - Apr 2015
Volume 25, Issue 3 - Mar 2015
Volume 25, Issue 2 - Feb 2015
Volume 25, Issue 1 - Jan 2015
Selecting the target year
Reduction of Booming Noise Using Damper Clutch Disk on the Drive Shaft of Commercial Small Truck
Kim, Yong Dae ; Choi, Byungjae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 377~383
DOI : 10.5050/KSNVE.2015.25.6.377
Torsion mode or bending mode of drive-line for rear-wheel drive vehicle exists in low frequency band. If resonance exists there between natural mode of driveline and powertrain excitation force, drive-line will manifest excessive vibration response. Also, the vibration response can be transmitted to vehicle body and can induce booming noise. A vehicle in this study exhibits a booming noise problem under specific transmission gear condition. To draw performance improvement plan, finite element analysis technique was used. Modification was evaluated qualitatively and priorities were derived. Finally, effectiveness of best modification was verified through test and full vehicle FE analysis.
Vibration Analysis of Rotating Pre-twisted Inward Beams with a Concentrated Mass
Lee, Gun Ho ; Yoo, Hong Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 384~390
DOI : 10.5050/KSNVE.2015.25.6.384
The vibration analysis of rotating inward beams considering the pre-twisted is presented based on Euler-Bernoulli beam theory. The frequency equations, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of angular speed, and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their result.
Swing Noise Reduction of an Excavator
Lee, Soyeon ; Won, Hong-In ; Kim, Woohyung ; Kim, Seongjae ; Kim, Indong ; Chung, Jintai ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 391~398
DOI : 10.5050/KSNVE.2015.25.6.391
The swing noise of an excavator is reduced in this study. When an excavator is under a swing motion, it produces the annoying noise which is required to be reduced. To identify the characteristics of the swing noise, the signals of noise and vibration from an excavator are measured during the swing motion. From the variation of the driving motor speed, the noise and vibration signals are picked up and plotted in the waterfall plots. From the waterfall plots, we identify the frequency components corresponding to the driving motor frequency, the gear mesh frequency of the planetary gear, and their harmonics. In addition, the natural frequencies and modes of the center frame are extracted by using the experimental modal test. It is found that the swing noise is amplified when the gear mesh frequencies coincide with the natural frequencies of the center frame. To reduce the swing noise, the structural modification is performed to the center frame. Finally, it is observed that the noise is considerably reduced by the structural modification.
Characterization of Axial Defects in Pipeline Using Torsional Guided Wave
Kim, Young-Wann ; Park, Kyung-Jo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 399~405
DOI : 10.5050/KSNVE.2015.25.6.399
In this work we use the mode decomposition technique employing chirplet transform, which is able to separate the individual modes from dispersive and multimodal waveform measured with the magnetostrictive sensor. The mode decomposition technique is also used to estimate the time-frequency centers and individual energies of the reflection, which would be used to locate and characterize axial defects. The arrival times of the separated modes are calculated and the axial defect lengths can be evaluated by using the estimated arrival time. Results from an experiment on a carbon steel pipe are presented and it is shown that the accurate and quantitative defect characterization could become enabled using the proposed technique.
Electrically Induced Damping Characteristics and a Relevant Requirement for the Maximum Power Generation in Piezoelectric Vibration Energy Harvesters
Kim, Jae Eun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 406~413
DOI : 10.5050/KSNVE.2015.25.6.406
The piezoelectric coupling in piezoelectric vibration energy harvesters with load resistance induces electrical damping as well as increase in the system stiffness. Starting from analytically deriving the explicit relations through governing equations in the frequency domain, this work identifies the characteristics of the electrically induced damping mechanism and shows that the electrically induced damping serves as a structural hysteretic damping on condition that a piezoelectric vibration energy harvester is excited at its short-circuit resonant frequency and its load resistor is optimally impedance- matched at the same time. Finally, it is analytically verified that the equivalence of a mechanical and an electrically induced damping ratio is required for the maximum power generation at a load resistor, which was claimed in some literature.
Torsional Vibration Phenomenon due to Pulse Torque of Variable Speed Induction Motor on Rotating Systems
Lee, Donchool ; Vuong, QuangDao ; Nam, Taekkun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 414~419
DOI : 10.5050/KSNVE.2015.25.6.414
Recently, commercial ships and other specialized vessels with electric propulsion system employ variable speed induction motor as its prime mover. The wide application of electrical motors also includes being the main drive system in most industrial machineries. However, during its start-up, shutdown, and brake switch operation, excessive torque variation are generated. As such, flexible coupling are installed in order to reduce the transmitted torque fluctuation to the driven side. In this paper, the pulse torque generated by an variable speed induction motor was analyzed theoretically and through measurement of torsional vibration. Induction motor with inverter on marine propulsion system and industrial compressor were used as experimental subjects. The study confirmed that pulse torque are generated regardless of motor speed and interpreted as a vibration source of the whole system. Results presented herein can be adopted as the basis in future amendment of inspection classifying body regulations.
Exact Solutions for Bending Vibration of Beam with Linearly Reduced width Along Its Length
Lee, Jung Woo ; Kim, Jung Ho ; Lee, Jung Youn ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 420~425
DOI : 10.5050/KSNVE.2015.25.6.420
In this paper a transfer matrix method is developed to solve for bending vibration of beam with linearly reduced width, and subsequently used to determine the exact natural frequencies for such problems. The differential equation, shear force, and bending moment are derived from Hamilton's principle, and the roots of the differential equation are computed using the power series solution of the Frobenius method. The effect of various taper ratio for bending vibration of beam with linearly reduced width is investigated in detail, and to validate the accuracy of the proposed method the results computed are compared with those given from commercial software(ANSYS).
Damping Force Characteristics of MR Damper with Additional Flow Path
Sohn, Jung Woo ; Oh, Jong-Seok ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 426~431
DOI : 10.5050/KSNVE.2015.25.6.426
In this work, a new type of MR damper with additional flow path in piston is proposed and damping force characteristics are numerically evaluated. Flow-mode type MR damper is considered and mathematical model is established based on Bingham rheological model of MR fluid to obtain accurate prediction of damping force characteristics. Damping force of the proposed MR damper are calculated with respect to piston velocity and input current. In addition, investigation on damping force characteristics is carried out according to number of additional flow path and excellence of the proposed MR damper is demonstrated.
Design of the Base for the Onboard Installed Equipment to Minimize Structure-borne Noise
Han, HyungSuk ; Lee, KyoungHyun ; Park, SungHo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 432~439
DOI : 10.5050/KSNVE.2015.25.6.432
In order to reduce the structure borne noise of the equipment sufficiently, its exciting force should be restricted and additional anti-vibration devices such as resilient mount and bellows should be applied. Since the structure borne noise is dependent on the design of the base for the equipment, it is very important to design the base with low vibration. Therefore, in this research, various types of the base design for the shipboard equipment are investigated to reduce the structure borne noise. In order to design the base with low vibration, the exciting force at the center of the gravity of the equipment is firstly defined through the experiment. Using the exciting force identified by experiments, various types of base designs for the typical turbo machine are evaluated by FEM(finite element method) analysis.
A Study on the Acoustic Baffle to Reduce Ghost Target According to Structure behind Cylindrical Array Sensor
Seo, Young Soo ; Kim, Dong Hyun ; Kim, Jin Tae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 25, issue 6, 2015, Pages 440~446
DOI : 10.5050/KSNVE.2015.25.6.440
Acoustic signal is emitted from a vessel and received by a cylindrical array sensor at some distance from the vessel. Acoustic signal is the source for a cylindrical array sensor which is designed to detect the acoustic signal. Cylindrical array sensors seldom have an ideal hydrodynamic shape and are not sufficiently robust to survive without some protection and they are normally housed in a sonar dome. Reflected signals by some structure inside a sonar dome make unwanted signals. Therefore, an acoustic baffle is used to minimize unwanted signals. The performance of the acoustic baffles can be determined from the acoustic numerical analysis at the design stage. In this study, finite element method was used to analyze the acoustic field around the cylindrical array sensor and baffle effects. The baffle performance can be defined the echo reduction. To show the baffle performance, the specimens were made for pulse tube test and echo reductions were measured during the test. In this paper, the effect of echo reduction of the acoustic baffle was discussed.