• 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.

• 한국소음진동공학회논문집
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• 제12권7호
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• pp.557-564
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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 evaluates in frequency domains. Experiments show vibration reduction capability of squeeze mode ER mount.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.832-837
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• 2001

In this paper, we analyzed the characteristic of the broken section for bolts fastening the generator casing, and according to the frequency analysis, we grasped the characteristic of the excited force, traced the path of the exciting source so that we examined a factor of transient vibration of the generator casing. Even if it appears transient vibration again, we applied spring washer and more tensile bolt to the casing to minimize the fracture. By solving troubles of the generator rotor, we reduced the vibration amplitude to the normal condition. So we obtain much more the reliablility of the generator.

• 한국소음진동공학회논문집
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• 제20권2호
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• pp.172-178
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• 2010

The multiple regression analysis and path analysis in each dominant area of noise source are conducted to analyze the relationship between dependent variables like annoyance and independent ones such as noise and non-noise factors. The multiple regression analysis shows that impact of noise factors is the highest to annoyance in dominant areas of road traffic and railway noise. Meanwhile, impact of non-noise factors such as sensitivity and satisfaction of environment on annoyance is also high in these areas. The path analysis result for multivariate analysis between various independent and dependent variables is similar to that of the multiple regression analysis. However, noise factor is the greatest factor influent on annoyance in the dominant areas of the combined noise, and relationship between annoyance and sensitivity is the highest in combined area exposed to road traffic noise and railway noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.604-609
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• 2002

In development of an advanced bicycle simulator, the investigation of the interactions between bicycle and rider during cycling is paramount important because bicycle is a two-wheeled human-powered vehicle. Tn this work, the tilt stability. among various interactions, of bicycling is investigated experimentally, In the experiments, the tilt angles of the bicycle, riders body and head are measured, as the riding p;1th and the speed are varied. Subjects are asked to ride along four typical paths on rigid flat ground : the straight, C-curved, S-curved and circle paths. The results from extensive experiments with different subjects can be summarized as : 1) The tilt angles of bicycle and rider are almost out of phase during pedaling along the straight path. 2) The bicycle tilt angle is nearly proportional to the square of bicycle speed for the straight and curved paths, and to the curvature for the curved paths. The head tilt angle is the biggest and the body tilt angle is the smallest for the straight path, but the tendency is reversed for the C-curved path. During the curve maneuvering, the rider's head tends to tilt by less than 40% of the bicycle tilt angle.

• 한국소음진동공학회논문집
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• 제18권8호
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• pp.805-815
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• 2008

Transfer path analysis(TPA) and panel contribution analysis(PCA) have been used widely to reduce interior noise of mechanical systems. TPA enables us to decompose interior noise into air-borne and structure-borne noises and estimate the path contribution of noise sources. PCA is also used to identify the noise contribution of each sub-panel in vibro-acoustic systems. In this paper, TPA and PCA are applied to wheel loader, one of the heavy construction equipments. Firstly, TPA for air-borne noise is conducted to estimate the contribution of air-borne sources using pressure transfer function. Thereafter, TPA for structure -borne noise is employed to verify the results of air-borne source quantification through the synthesis of two results. Secondly, PCA is performed by both TPA using pressure transfer function between panels inside the cabin and boundry element method(BEM) for the cabin of wheel loader with various boundary conditions. As a results, it was found that TPA conducted by experiments and PCA accomplished by both experiments and BEM are very effective methods in analyzing the path and contribution of the noises for reducing an interior noise level in the wheel loader system.

• 환경영향평가
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• 제22권4호
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• pp.381-387
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• 2013

In order to improve the environmental vibration, it is necessary to method for not only reduce the vibration source, but also control the vibration path. In this study, we used borebole for estimate the vibration reduction. And also, we analyzed displacement and vibration velocity caused by the position of borehole as well as the condition of borehole in ground structure. Visual FEA(Finite Element Analysis) program was used in this numerical analysis. The results are as follows : The displacement magnitude and X, Y direction displacement were represented to different results due to the condition and position of borehole, and were represented to the lowest values when the position of borehole is the most close condition from the vibration source. And also, the vibration velocity was decreased as using borebole in ground structure. The isolation efficiency of the vibration was calculated to maximum 18.40% when borehole was established to the most close position from the vibration source and the receive point.

• 한국기계가공학회지
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• 제8권2호
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• pp.32-39
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• 2009

This paper describes mathematical models of the torsional geared driving system for the indexing path and the mill driving path in a mill turret. The eigenvalue analysis for the models is conducted both with and without the gear contact stiffnesses. The natural frequency leads to the effect of gear contact stiffnesses on the vibration of torsional geared systems in a mill turret. It is necessary to analyze eigenvalues of the complex geared torsional system in order to prevent the unexpected vibrations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.109-111
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• 2007

Community Noise has been great concerned in public. A road traffic noise has affected too much damage on quiet living environment. In this paper, the noise barrier effect on the street has been examned. As a tool of the path analyses, a cepstrum analyses of signal processing technique has been implemented.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.518-523
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• 1995

To improve the set comfort of commercial vehicles in various road conditions, it is necessary to design a seat shock absorber which can avoid the vibration zone imposing the discomfort feeling and fatigue on drivers. Through the vibration and dynamic analysis, a shock absorber that has 4 steps of damping ability is developed. Dynamic characteristics analysis of the seat damper is performed considering each valve and oil path for the design purpose.