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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 24, Issue 12 - Dec 2014
Volume 24, Issue 11 - Nov 2014
Volume 24, Issue 10 - Oct 2014
Volume 24, Issue 9 - Sep 2014
Volume 24, Issue 8 - Aug 2014
Volume 24, Issue 7 - Jul 2014
Volume 24, Issue 6 - Jun 2014
Volume 24, Issue 5 - May 2014
Volume 24, Issue 4 - Apr 2014
Volume 24, Issue 3 - Mar 2014
Volume 24, Issue 2 - Feb 2014
Volume 24, Issue 1 - Jan 2014
Selecting the target year
Transient Torsional Vibration Analysis of Ice-class Propulsion Shafting System Driven by Electric Motor
Barro, Ronald D. ; Lee, Don Chool ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 667~674
DOI : 10.5050/KSNVE.2014.24.9.667
A ship's propulsion shafting system is subjected to varying magnitudes of intermittent loadings that pose great risks such as failure. Consequently, the dynamic characteristic of a propulsion shafting system must be designed to withstand the resonance that occurs during operation. This resonance results from hydrodynamic interaction between the propeller and fluid. For ice-class vessels, this interaction takes place between the propeller and ice. Producing load- and resonance-induced stresses, the propeller-ice interaction is the primary source of excitation, making it a major focus in the design requirements of propulsion shafting systems. This paper examines the transient torsional vibration response of the propulsion shafting system of an ice-class research vessel. The propulsion train is composed of an electric motor, flexible coupling, spherical gears, and a propeller configuration. In this paper, the theoretical analysis of transient torsional vibration and propeller-ice interaction loading is first discussed, followed by an explanation of the actual transient torsional vibration measurements. Measurement data for the analysis were compared with an applied estimation factor for the propulsion shafting design torque limit, and they were evaluated using an existing international standard. Addressing the transient torsional vibration of a propulsion shafting system with an electric motor, this paper also illustrates the influence of flexible coupling stiffness design on resulting resonance. Lastly, the paper concludes with a proposal to further study the existence of negative torque on a gear train and its overall effect on propulsion shafting systems.
Development of EMD-based Fault Diagnosis System for Induction Motor
Kang, Jungsun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 675~681
DOI : 10.5050/KSNVE.2014.24.9.675
This paper proposes a fault diagnosis system for an induction motor. This system uses empirical mode decomposition(EMD) to extract fault signatures and multi-layer perceptron(MLP) neural network to facilitate an accurate fault diagnosis. EMD can not only decompose a signal adaptively but also provide intrinsic mode functions(IMFs) containing natural oscillatory modes of the signal. However, every IMF does not represent fault signature, an IMF selection algorithm based on harmonics and their energy of each IMF is proposed. The selected IMFs are utilized for fault classification using MLP and this system shows approximately 98 % diagnosis accuracy for the fault vibration signal of the induction motor.
The Noise Influence Assessment according to the Change of the Offset Type Print Machine's Power
Gu, Jinhoi ; Kwon, Myunghee ; Lee, Wooseok ; Lee, Jaewon ; Park, Hyungkyu ; Kim, Samsu ; Yun, Heekyung ; Lee, Kyumok ; Jung, Daekwan ; Seo, Chungyoul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 682~686
DOI : 10.5050/KSNVE.2014.24.9.682
Nowadays, the needs to revise the classification criteria for noise emission facilities have been suggested by the related industries. Because there existed many reasonable factors in the criteria regarding the noise emission facilities. And the noise emission facility classification criterion of the print machine changed from 50 HP to 100 HP in 2013. But the increasement of the noise emission facility classification criterion of the print machine can cause adverse effects like the bigger noise. So, in this paper, we measured the print machine's sound power level according to the changes of the print machine's power to assess the adverse effects. The measurement method applied with KS I ISO 9614-2(1996). The corelation between the sound power level and the power of print machines was analyzed by regression analysis. In this paper, we found that the sound power level of the print machines can increase about 1.3 dB in the condition of that the power of print machine increases from 50 HP to 100 HP. And we found that the sound power level of the print machines can increase about 1.0 dB for a increasement of 1,000 SPH(sheet per hour) of printing speed. The noise emission characteristics of print machine stuied in this paper will be useful to design the noise reduction plan in the future.
Experimental Review on Dynamic Characteristics of the Commercial Mounts for Vibration Reduction
Moon, Seok-Jun ; Shin, Y.H. ; Chung, J.H. ; Song, C.K. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 687~694
DOI : 10.5050/KSNVE.2014.24.9.687
The mount suppliers are providing limited information on the dynamic characteristics of the mounts to some designers and some manufacturers of the high-precision machines. In this technical study, the experimental review was carried out about dynamic characteristics of five kinds of commercial passive mounts sold in the market. The dynamic characteristics, natural frequency and damping ratio, extracted from experimental tests were compared to the materials supplied by mount makers. In order to predict the performance of the high-precision machines with mounts, exact values of the dynamic characteristics of mounts should be used in the stage of numerical analysis.
Prediction of Radiated Sound on Structure-acoustic Coupled Plate by the Efficient Configuration of Structural Sensors
Lee, Ok-Dong ; Oh, Jae-Eung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 695~705
DOI : 10.5050/KSNVE.2014.24.9.695
In this paper, two types of techniques for the prediction of radiated sound pressure due to vibration of a structure are investigated. The prediction performance using wave-number sensing technique is compared to that of conventional prediction method, such as Rayleigh's integral method, for the prediction of far-field radiated sound pressure. For a coupled plate, wave-number components are predicted by the vibration response of plate and the prediction performance of far-field sound is verified. In addition, the applicability of distributed sensors that are not allowable to Rayleigh's integral method is considered and these can replace point sensors. Experimental implementation verified the prediction accuracy of far-field sound radiation by the wave-number sensing technique. Prediction results from the technique are as good as those of Rayleigh's integral method and with distributed sensors, more reduced computation time is expected. To predict the radiated sound by the efficient configuration of structural sensors, composed(synthesized) mode considering sound power contribution is determined and from this size and location of sensors are chosen. Four types of sensor configuration are suggested, simulated and compared.
Developing Tuned Mass Damper of Adjustable Damping Type to Control the Vibrations of Medical Robots
Cha, WoonYong ; Chun, ChongKeun ; Park, SangGon ; Han, HyunHee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 706~715
DOI : 10.5050/KSNVE.2014.24.9.706
Recently, the medical community has been enthusiastically welcoming robots that are able to provide high-quality medical services across the board, including assisting the surgeons during surgeries. In response, many higher education institutions and research facilities started to conduct various experiments and studies about these robots. During such research, it was discovered that the arm of one particular robot type that is being developed to assist surgeries are prone to vibrate even from the weakest impact, in addition to other residual vibration problems. We attempted to reduce such dynamic response by using a MF-TMD that is produced by adding magnetic fluid to ECD. We verified the MF-TMD's performance by testing it within various frequency bands and attenuations. We then designed a cantilever that was structurally similar to the robot's arm. We attached the MF-TMD to this cantilever and conducted a pilot experiment, which validated our hypothesis that MF-TMD will reduce the robot arm's vibrations through its optimal damping ratio. Henceforth, we attached the MF-TMD to the robot arm in question and conducted a performance experiment in which we tuned the MF-TMD's frequency and damping factor to its optimal level and measured the vibrations of the arm. The experiment demonstrated that the vibrations that occurred whenever the arms rotated were significantly reduced.
Enhancement of Displacement Resolution of Vibration Data Measured by using Camera Images
Son, Ki-Sung ; Jeon, Hyeong-Seop ; Han, Soon Woo ; Park, Jong Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 716~723
DOI : 10.5050/KSNVE.2014.24.9.716
Vibration measurement using image processing is a fully non-contact measurement method and has many application fields. The resolution of vibration data measured by image processing depends on the camera performance and is lower than that measured by accelerometers. This work discusses the method to increase resolution of vibration signal measured by image processing based on the image mosaic technique with a high-power lens. The working principle of resolution enhancement was explained theoretically and verified by several experiments. It was shown that the proposed method can measure vibrations of relatively large scale structures with increased resolutions.
Measurement of Loss Factor and Young's Modulus of ABS and PP Specimens by Using a Speaker
Jeon, Byeong Su ; Jung, Sung Soo ; Lee, Jong Kyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 724~730
DOI : 10.5050/KSNVE.2014.24.9.724
It is essential to control noise and vibration in various industrial fields. In the automobile industry, various plastics have been developed and replaced metallic materials in order to reduce mass and vibration effectively. In this study, we measured and analyzed the Young's moduli and the loss factors of Acrylonitrile butadiene styrene(ABS) and Polypropylene(PP). In order to solve the fundamental error to determine the two quantities, a loudspeaker was used instead of conventional electromagnetic devices to generate bending motion to the specimens and a laser vibrometer was also used in detection of vibration signal of the specimen. The measured Young's moduli and loss factors of the ABS specimen were nearly constant as the temperature(
) was increased. The loss factor of PP specimen showed peak value at
and it means that there is glass transition for the PP specimen. Young's modulus of PP specimen was linearly decreased as the temperature was increased.
Investigation for the Characters of Human Perception Level according to Acceleration Value Parameters
Lee, MinJung ; Han, SangWhan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 24, issue 9, 2014, Pages 731~740
DOI : 10.5050/KSNVE.2014.24.9.731
Occupants induced floor vertical vibrations may cause other occupant's annoyance and lead to social loss. To help control such floor vibrations, several criteria have been developed mostly based on human perception tests and floor vibration tests. Floor vibration is evaluated by comparison with criteria and vibration parameters of subject floor, such as frequency, damping ratio, acceleration value, vibration duration time and occurrence frequency. Three acceleration value parameters are used in criteria; peak acceleration, rms acceleration and VDV, when a floor vibration serviceability is evaluated. Meanwhile rms acceleration and peak acceleration are adopted as vibration limit value in criteria and researches of human perception for vibration. Occupants induced floor vibration is transient rather than steady state. However, rms acceleration is not reliable parameter for evaluating transient vibration. The objective of this study is to investigate the characters of human perception level according to acceleration value parameters for vibration induced by heel impacts and walking activities.