• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.6
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• pp.391-398
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• 2015

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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.153-159
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• 1997

This paper presents the swing motion analysis of the container crane headblock with the passive control device using hydraulic motors and anti-swing ropes. The device hauls at the headblock to opposite direction of its swing motion using the tension difference between anti-swing ropes connected to the headblock. To consider this control mechanism, the headblock is modelled as the rigid bar suspended by two hoist ropes at the overhead trolley and its non-linear equation of motion is derived using Lagrange's equation. Some numerical experiments using the equation are carried out to investigate the swing motion characteristics of the headblock under the variation of geometric relation among the cargo handling components and to evaluate the performance of the anti-swing device.

• Journal of Biomedical Engineering Research
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• v.41 no.6
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• pp.264-271
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• 2020

The purpose of this study was to investigate the effects of active vibration exercise of upper limb on physical capacity index (endurance, grip strength, balance, and flexibility) and vasomotor index (capillary length and body surface temperature) in middle aged women. 20 participants randomly divided into two groups: vibro-swing exercise (VSE) and non vibro-swing exercise (NVSE). Subjects in each group measured the 30 second arm curl test, hand dynamometer, one leg standing test, back scratch test, nail fold capillary microscope (NFM), and digital infrared thermal imaging (DITI) before and after exercise. The results showed that active vibration exercise of upper limb with vibro-swing equipment increased the endurance, balance ability, and the capillary length. In addition, changes in body temperature immediately after exercise were predicted to affect vasomotor. Active vibration exercise of upper limb has the advantage of being able to exercise anywhere regardless of the location by inducing different frequency changes in movement of various ranges and velocity. For this reason, the combination of vibration and active movement can be expected the physiological effects when producing exercise programs for middle aged women.

• Journal of the Korean Society for Railway
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• v.6 no.4
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• pp.215-220
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• 2003

In this paper the dynamic characteristics of a Swing Motion Bogie, such as a critical speed and a carbody vibration, are investigated in reply to the request of the Meridian Rail Corporation in the United States. Also described are experimental results of the maximum speed, the derailment coefficient, the lateral force, the vertical force, the vibration acceleration and steady state lateral acceleration measured from main line tests.

• Journal of KSNVE
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• v.7 no.5
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• pp.765-772
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• 1997

This paper presents the swing motion analysis of the container crane headblock with the passive control device using hydraulic motors and anti-swing ropes. The device hauls at the headblock to opposite direction of its swing motion using the tension difference between anti-swing ropes connected to the headblock. To consider this control mechanism, the headblock is modelled as the rigid bar suspended by two hoist ropes at the overhead trolley and its non-linear equation of motion is derived using Lagrange's equation. Some numerical experiments using the equation are carried out to investigate the swing motion characteristics of the headblock under the variation of geometric relation among the cargo handling components and to evaluate the performance of the anti-swing device.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.8
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• pp.843-849
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• 2009

The reliable operation of a swing check valve in the main feed water system of a power plant is most essential for successful shout-down process. A failure to close the valve at proper time often leads to the instability of the main feed water system, or even to an emergency stop of the power plant. In reality it is a very difficult task to monitor the behavior of a swing check valve. Furthermore it is impossible to see the motion of the valve. In this work two measurements were carried out simultaneously to determine the precise valve closure time. The dynamic pressure measurements were made at the inlet and outlet regions of the swing check valve. The transient vibration of the valve housing in the direction of water flow was also measured, which enabled the measurement of the transient vibration of the valve housing near valve closure. By comparing the results produced from these measurements the precise valve closure time could be determined. By carrying out order tracking technique using the dynamic pressure signals and pump rpm signal, the complicated dynamic problems inside the main feed water system can be more easily dealt with. This measurement scheme might be implemented in a power plant on a real-time basis without much difficulty. If this could be implemented, valuable information essential for shut-down operations can readily be passed on to the main control room. The feasibility of this implementation was demonstrated by this experimental work.

• Proceedings of the KSR Conference
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• 2002.10b
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• pp.892-897
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• 2002

The research was requested by Meridian Rail Corporation in United States. The Swing Motion Bogie can application by Korea style if synthesize study result of bogie strength evaluation, bogie dynamic characteristics analysis, actual test(maximum speed, derailment coefficient, lateral force, vertical force, vibration acceleration, steady state lateral acceleration) etc..

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.138-144
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• 2000

Degradation occurred at the 6 inch swing check valve in nuclear power plant. Valve replacement and maintenance were carried out during the plant O/H. This report examined the degradation mechanism of the 6 inch check valve by the experimental and theoretical study. Results shows that the degradation was caused by valve chattering which due to the structural and acoustic resonance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.70-74
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• 2004

There are many researches being in process to develop the information storage devices applying to the portable devices recently. Based on this need, the information storage devices have to be satisfied with the fast access time, the robustness of the system, high data transfer rate and lower media price. The total size of the drive must design to adapt the portable devices such as CF II card or PC II card size. This paper proposes the swing arm type actuator to insert the designed actuator in the drive of the CF II size. Hereafter the research will be going on to be suitable to the physical standard and design the focus magnetic circuit newly. The swing arm type actuator including this circuit is designed to have the dynamic characteristic satisfying the mechanical specification as well as the BD 1x. Finally, the adaptability to the portable devices was demonstrated by the finite element analysis and optimization of structural part.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1161-1163
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• 1996

In this paper, a simulator is designed along with S/W package for crane controllers. Due to trolley's acceleration or deceleration, cranes inherently cause swing motion of the objects in transporting heavy objects. This swing not only deteriorates the crane handling safety but also increases the processing time. To overcome these drawbacks, the fuzzy rule-based simulator is developed with inhibitory swing at final action. The computer simulation shows that the swing at initial and final positions is removed fast with small position error. The proposed simulator can be used for handling object stablely and the study of effectiveness in unmanned operation of cranes.