• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.317-320
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• 2002

The effect of vibration on the viscosity of a shear-thinning fluid was investigated with a newly designed pressure-scanning capillary viscometer. The viscometer was designed to measure non-Newtonian viscosity continuously over a range of shear rates at a time. Low frequency vibration was applied perpendicularly to the direction of the flow. The effect of the transversal vibration was investigated for both Newtonian fluids and non-Newtonian fluids. The experimental results showed that the vibration had no effect on the viscosity of the Newtonian fluids. However, the vibration caused a significant reduction of the shear-thinning fluid viscosity. The viscosity reduction was strongly dependent on both vibration frequency and shear rate. In addition, the viscosity reduction was affected by the amplitude of vibration, and, the bigger amplitude applied, the more viscosity reduction occurred.

• 한국환경복원기술학회지
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• 제9권1호
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• pp.31-40
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• 2006

This paper describes the results of a series of field experiments which are carried out to assess the reduction effect of railroad vibration by utilizing waste tires. The ground vibration due to train service is measured in Honam Railroad line and Kyongbu Railroad line to assess the ground vibration with the domestic railroad line and train type before field model test. From the results of these tests, frequency on train service is presented from 5Hz to 100Hz and a range of excellence frequency is presented to be about from 20Hz to 40Hz in the domestic railroad line. Also, plate bearing tests are conducted to evaluate the variation of bearing capacity with different thickness of the waste tire layer and the fill layer. Finally, field model test is performed by using tire chips ($5cm{\times}5cm$ in size) as a reduction material of railroad vibration. The reduction effect of railroad vibration by utilizing waste tires increases with increasing the thickness of the waste tire layer and the frequency of the vibration source. The results of this experimental study was shown that the waste tire can be used for reduction of the railroad vibration.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.146-149
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• 2005

Thesedays, the reduction of hand-transmitted vibration of hand-held power tools is important issue for operators' welfare, In the study, frequency response function is measured and vibration total value is evaluated for solving the principle and effect of the BOSCH's vibration-proof handle. This handle functions as a dynamic damper and has the effect, 22% vibration total value reduction under idling condition using a system that consists of a PC with data acquisition system and LabVIEW program. The program in the system makes it possible to evaluate vibration total value according to ISO 5349. This handle offers a good example for figuring out the physical contradiction between the work efficiency and operators' health.

• 소음진동
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• 제3권4호
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• pp.325-330
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• 1993

The longitudinal vibration of the tape in the tape transport system influences the performance of the nagnetic tape-recording system. Generally it is controlled by a passive method with impedance roller which is easy to implement and cost-effective. Therefore the effect of the impedance roller in reducing the tape vibration was analyzed in this paper. The practical tape transport system was modelled mathematically as a mass-spring system. Both simulation and experimental study were carried out in order to show the vibration reduction effect of the impedance roller.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.911-916
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• 2002

One of important roles of concrete track is to reduce vibration transmitting to subgrade. In this paper, a numerical method for evaluating the effects of vibration reduction of concrete track is presented. Using the method, high frequency dynamic analyses and track-tunnel-soil interaction analyses are carried out for three types of concrete track in order to investigate the vibration reduction effects compared with normal ballast track.

• 한국재난정보학회 논문집
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• 제20권3호
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• pp.549-562
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• 2024

연구목적: 본 연구는 수도권 광역급행열차 운행에 따른 열차진동을 진동차단벽을 설치하여 저감시키는 경우 차단벽의 설계조건에 따른 진동저감효과를 확인하였다. 연구방법: 설계조건 중 진동저감에 영향을 끼치는 인자를 파악하기 위해 설계조건 중 채움재의 강성비와 차단벽의 설치심도만을 달리하여 결과를 확인하였다. 연구결과: 채움재는 강성채움재보단 연성채움재를 사용한 경우 진동저감효과가 더 뛰어났으며 연성채움재의 경우 지반과 채움재간의 강성비가 0에 가까울수록 진동저감효과가 뛰어난 것으로 나타났다. 또한 차단벽의 설치심도가 깊을수록 진동차단효과가 대체적으로 뛰어난 것으로 나타났으며 차단벽의 심도가 너무 얕은 경우 오히려 수진점에서 진동이 증폭하는 현상이 발생하였다. 결론:진동저감효과가 가장 뛰어난 설계조건은 강성비 0.08, 설치심도 15 m인 경우로 이 때 진동원과 10 m 떨어진 수진점에서의 진동저감율은 60.34%로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1439-1443
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• 2007

In this paper, vibration reduction techniques of a voice coil motor (VCM) actuator are presented for AFM imaging system. The damping coefficient of the actuator driven by VCM with a flexure hinge is quite low and it cause the about 30dB peak amplitude response at the resonance frequency. To decrease this peak response, we design and apply elliptical band-stop filters to xy and z axis VCM actuator. Frequency response of each actuator with filter is measured to verify the effect of the filters. As a sensor, capacitive sensor is used. Vibration reduction rate of the xy actuator with the filter is also measured while real AFM scanning condition. As another method, closed loop control with the capacitive sensor is applied to the xy axis actuator to add an electrical damping effect and vibration reduction rate measured. These vibration reduction rates with each method are compared. In the case of z axis actuator, the frequency response of force (gap) control loop is measured. For comparison, the frequency response using a conventional PID controller is also obtained. Finally, the AFM image of a standard grid sample is measured with the designed controller to analyze the effect in the AFM imaging.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.375-380
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• 2001

Generally, countermeasures for the train-induced vibration are divided into the measures at the source, propagation path and receiving object. Among these measures the countermeasure at the source location is the most active and effective one in the field of railroad. In this study, the effectiveness of each anti-vibration measures at the track(source location) such as elastic rail fastener, ballast mat were evaluated through the comparison of acceleration level, insertion loss at the installed locations of each measures. As result of field measurement of vibration at the railroad track supporting structures and on the ground nearby the structures, elastic rail fastener showed vibration reduction effect of 4.5 ∼7.3㏈ on the concrete slab, 1.6∼3.7㏈ on the ground with the train operation speed of 80km/hr. In the case of ballast mat, the vibration reduction effect at the concrete slab and on the ground were 11.9∼13.3㏈ and 6.1∼7.6㏈, respectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.305-309
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• 2006

In this paper vibration reduction characteristics of floating floors used in railway vehicles are studied. Vibration reduction characteristics are compared through a series of tests for elastically-coupled floor and rigidly-coupled floor. It was found that elastically-coupled floor has larger vibration reduction amount than rigidly-coupled floor. Around the fundamental natural frequency, however, elastic floor has poor vibration reduction effect than rigid floor. Measures to reduce structure-borne noise are also discussed based on the test results. Structure-borne noise for running railway vehicles cannot be reduced by an effort to deviate resonance between natural frequency of floors and major exciting forces. Instead, reducing vibration level of top floor and using covers which have low sound radiation coefficient will be effective for reducing structure-borne noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.423-426
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• 2007

In this paper, vibration reduction of resiliently mounted machinery and effect of the foundation impedance is studied. SBN (Structure-borne noise) reduction through the mount is analyzed by assuming that the system is modeled as a mass-spring system, while the impedance of the floor is included in the prediction. The comparison of the SBN difference through the mount between predictions and measurements show that the slopes are similar in the case of single-mount system, while the measurements differs significantly from the predictions in the case of the double-resilient system.