• 한국철도학회논문집
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• 제16권5호
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• pp.358-364
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• 2013

전편에서 제시되었던 진동소음 데이터를 기초로 하여 철도차량기지 주변에 기 건설되어 있던 고층아파트 단지의 진동소음 방지대책 수립에 필요한 쟁점들을 검토하고 설계단계에서 필요한 방진기법을 논하였다. 특히, 차량운행속도, 인공대지의 물리적 특징, 건축물 지지구조의 물성치, 아파트 층별구조의 동특성 등에 대하여 진동측면에서 논의하였다. 논문에서 제안된 설계변수와 사례는 향후 개발 예상되는 철도 주변 부지 건축물의 환경문제를 최소화하는 가이드라인으로 사용될 수 있다. 특히, 주민이 거주하는 건축물에 대해서는 설계단계에서부터 합리적인 소음진동 방지대책의 적용이 요구되며, 적극적인 대책을 수립하면 사회적인 비용 또한 저감될 수 있을 것으로 판단된다.

• 한국자동차공학회논문집
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• 제2권2호
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• pp.24-32
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• 1994

This paper is the experimental study on the vibration reduction of the 4WD vehicle through the change of the engine mounting conditions.(4 stroke diesel engine) The engine mounting conditions are changed to reduce the transmitted vibrations of the engine to the frame at the idle speed. Under the assumption that the Powertrain(Engine Transmission and Transfer Case) is a rigid body, the inertia properties of the powertrain are obtained by experimental modal analysis. And then the changed mounting conditions are studied by the decoupled vibration theory and analytical model of six degree of freedom. Though the mounting conditions are changed to improve the vibration isolation at idle speed, the vibration and the interior noise of the vehicle are reduced significantly at driving speed as well as idle speed. From the indirect endurance test of the front engine mounts, the changed mounting conditions are desirable to endurance as well as vibration reduction of the 4WD vehicle.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.370-375
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• 2009

The purpose of this study is to reduce the vibration of the computer by developing the vibration absorber and damper. The eccentricity of the cooling fan causes the vibration of the computer. We designed the material properties of the vibration absorber by FEM model within operation frequencies of the cooling fan. We experiment the overall analysis and system analysis. The vibration of cooling fan is measured by using a laser vibrometer. The result shows that the proposed vibration absorber and damper reduce the vibration of the computer.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.221-228
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• 1999

A full-time four wheel drive vehicle is driven literally full time by the front and the rear wheels. Front and rear drive shafts are rotated rapidly in the extremely torsional state, which can cause various vibration and noise problems. The purpose of this study is to reduce the vibration and the noise of the full -time four wheel drive vehicle. In this paper, both the causes and the methods for reduction of torsional vibration are suggested. For this study, the characteristics of the torsional vibration are analyzed by free and forced torsional vibration simulation. And this paper described the influence upon the torsional vibration with emphasis shafting system. The validity of simulation models is checked by the field test. The forced vibration simulation with the variations of shaft design factors are performed by the checked models. According to the simulation , the resonance region shifts and the torque fluctuation varies in the system,. Finally, the methods and the effects for the torsional vibration reduction in driveline are proposed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.477-485
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• 2007

When Korean High Speed Train (KTX) runs over a high-speed railway bridge, the high-speed railway bridge gives quite large acceleration response. Local vibration at the large cross section, the impact from equally spaced sleepers, the vibration due to elastomeric bearings, and the vibration from the train itself are the causes of this acceleration response. Maximum peaks of the accelerations measured at the bridges are sometimes going over the limit value. Although it is smaller than 0.35G, the limit from the Korean Bridge Design Manual(BRDM), this acceleration response should be reduced for the safety of running trains with high speed. In this paper, to reduce the acceleration response by controlling excessive local vibration at the large cross section, vibration reduction method is studied. The result shows that the effect of elastomeric bearings on the vibration of the bridge is very large and that the vibration reduction device is effective against wing mode local vibration PSC box girder bridge for the high-speed railway, which usually has very large cross section, although it has little effect on global vibration modes such as flexural and twisting modes. The test of the vibration reduction device on the bridge in service has been performed in this study.

• 소음진동
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• 제5권1호
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• pp.75-83
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• 1995

The fluctuation of the engine torque appears to be the major source of the torsional vibration of the automotive driveline. The reduction of this torsional vibration has become a significant problem, due to an increase in the fluctuation of the torque of recent light weighted and high powered engines, along with the requirements of higher performance. The torsional vibration of the automotive driveline can be reduced by smoothing the fluctuation by adjusting the torsional characteristics of the clutch-disc. This paper presents an experimental and theoretical research on the clutch-disc torsional characteristics for the reduction of the torsional vibration at driving. The effects of clutch-damper on diminishing the torsional vibration were investigated experimentally. A dynamic model for the automotive driveline was developed, and the engine torque of the model were evaluated with experimental data. By executing a simulation using the model, it has become possible to obtain the clutch-disc torsional characteristics and the clutch-disc torsional characteristics for reducing the torsional vibration has been suggested. The results are as follows: (1) By exceuting simulations using nonlinear model of four degrees of freedom, a design technique to determine the clutch-disc torsional characteristics for reducing the torsional vibration at driving was developed. (2) The influence of barious torsional characteristics of the clutch has been studied in examining design parameters, which indicates that the domain to minimize the torsional vibration at driving depends on the characteristics of the clutch-damper, i. e., spring constant and hysteresis.

• 한국소음진동공학회논문집
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• 제18권11호
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• pp.1192-1198
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• 2008

In this paper, the vibration and shock of an HDD car-holder are reduced through vibration analysis and a structural modification. In order to identify the exciting frequency components of vibration and shock, vibration signals are measured and analyzed from the wind shield or dashboard. In addition, the modal test for the current HDD car-holder is performed to investigate the dynamic characteristics of the car-holder. From these experiments, it is found that the exciting frequencies coincide to the natural frequencies of the car-holder. For the purpose of avoiding resonance, some FEM simulations are carried out and then structural modifications are made for the car-holder. Based on the results of simulations, a prototype of new car-holder are manufactured and tested to demonstrate the reduction of vibration and shock. It is verified by the test that a considerable amount of vibration and shock are reduced.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.499-504
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• 2002

To reduce unwanted vibrations in war ship which may be transmitted through underwater path, it is required to use high damping mounts to isolate the vibration. In this work, the beam structure with squeeze mode ER mount is proposed and response characteristics such as acceleration and force transmissibility of beam with constant voltage and optimal controller are experimentally analyzed. The controller is empirically realized and control responses are evaluated in frequency domains. Experiments show vibration reduction capability of squeeze mode ER mount.

• 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.

• 한국정밀공학회지
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• 제21권7호
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• pp.107-114
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• 2004

This paper presents a two-time scale approach for vibration reduction of a high speed Cartesian manipulator. High speed manipulators would be subject to mechanical vibration due to high inertia forces acting on linkages. To achieve high throughput capability, such motion induced vibration would have to be damped quickly, to reduce settling time of the manipulator end-effector. This paper develops a two-time scale model fer a structurally-flexible Cartesian manipulator. Based on the two-time scale model, a composite controller consisting of a computed torque method for the slow time-scale rigid body subsystem, and a linear quadratic state-feedback regulator for the fast time-scale flexible subsystem, is designed. Simulation results show that the proposed two time-scale controller yields good performance in attenuating structural vibration arising due to excitation from inertial forces.