• 한국소음진동공학회논문집
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• 제14권8호
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• pp.749-756
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• 2004

While designing shafting in reciprocating machines with internal combustion engines which derive generators, pumps, and vehicles, it is very important to calculate the additional stress of shafting by torsional vibration. In this paper, the transfer stiffness coefficient method which is based on the successive transfer of stiffness coefficient was applied to the calculation of the additional stress of shafting in reciprocating machine by torsional vibration. In order to confirm the effectiveness of the present method, a propulsion shafting with a diesel engine in a vessel was considered as the computational example of shafting in reciprocating machine. The results calculated by the present method were compared with those of the modal analysis method, the mechanical impedance method, and free vibration analysis.

• 제어로봇시스템학회논문지
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• 제15권11호
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• pp.1076-1079
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• 2009

This article deals with an optical image stabilizer which moves an image sensor in the direction of cancelling the vibration caused by hand shaking to prevent a photographed image from blurring. The ball-guide way method adopted as a transfer device of the image sensor is easy to be manufactured because of its simple structure and is suitable to minimize the friction between mechanisms, but has weakness of a chance of physical defect such as groove and rising. In case that the movement of the transfer device equipped with the image sensor is blunted because a ball is stuck in defects of guide way, the performance of the image stabilizer falls down drastically. We propose a method to prevent the transfer device from blunting by applying artificial vibration. At this time, the artificial vibration should be designed under consideration of dynamic characteristics and specifications of the system to be discriminated from the vibration caused by hand shaking.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1071-1077
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• 2010

The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness(NVH) engineers. A passenger vehicle has various and complicated transmission paths of sound and vibration. In order to identify the mechanism of transfer path, estimation of excitation force and exact modeling of transfer path are required. This paper presents method for estimating the noise source contribution on the road noise of the vehicle in a multiple input system where the input sources may be coherent with each other. And vector synthesis technique is employed to identify the characteristics of road noise and its transmission to vehicle compartment through noise and vibration analysis. Vibration reduction efficiency of each transfer path is evaluated by comparing individual vector components obtained virtual simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.774-781
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• 2006

This paper presents a study on the analytical prediction of vibration transmission from helical gears to the bearing. The proposed method is based on the application of the three dimensional helical gear behaviors and complete description of shaft by the spectral method. Helical gear system used in this paper consists of the driving element, helical gears, shafts, bearings, couplings and load element. In order to describe all translation and rotation motion of helical gears twelve degree of freedom equations of motion by the transmission error excitation are derived. Using these equations, transfer matrix for the helical gear is derived. For the detail behavior of shaft motion, the $12{\times}12$ transfer matrix for the shaft is derived. Transfer matrix for the bearing, coupling, driving element, and load is also derived. Application of the boundary conditions in the assembled transfer matrix produces the forces and displacements in each element of the helical gear system. The effect of the proposed method is shown by numerical example.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.157-162
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• 1998

Dynamic loads may arise from rotating parte of pump if they are insufficiently balanced. The magnitude of pump induced vibrations varies according to the weight, eccentricity, and unbalanced mass of pump. This is a study to estimate the pump induced vibration in time and frequency domain by transfer function. The transfer function has real and imaginary information of signals, and response function has also real and imaginary information. So the vibration force can be obtained from the response and transfer function by complex calculation. The amplitudes and components of 50Hp pump vibration force are suggested.

• 에너지공학
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• 제13권4호
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• pp.275-280
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• 2004

관내부로 흐르는 물에 초음파 진동을 가진 하였을 때 관내 열전달이 증진되는 효과를 실험 및 수치해석을 통해 연구하였다 원형관 벽면에서 관내부로 흐르는 물로의 대류 열 전달계수를 초음파 진동이 있을 때 와 없을 때에 측정하였다. 이 결과를 비교함으로써 초음파진동이 전열성능 향상에 미치는 영향을 정량화 하였다. 이러한 현상에 영향을 줄 수 있는 유량과 온도의 범위를 넓히기 위하여 수치해석을 수행하였다. FLUENT 6.1을 이용하여 관내의 유동장과 온도분포를 해석하고 초음파 진동 유무 시 대류 열 전달계수를 평가하였다 연구결과 초음파진동이 강제대류 조건에서 전열성능을 향상시키며 그 영향은 관내를 흐르는 물의 유량에 따라 크게 변한다는 것을 보여주고 있다.

• 소음진동
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• 제8권5호
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• pp.799-806
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• 1998

Noise and vibration due to railway traffic are major causes of environmental pollution in the city. In course of judging, assessing and coping with the problem, it becomes imperative to predict the vibration level induced by railway traffic passing through downtown in the city. The vibration due to railway traffic is transferred to the neighbouring buildings through the ground. In this study, as a method predicting vibration level of the buildings near railway, a vibration transfer formula is suggested. This formula is used to calculate vibration level occuring at the bottom of the neighbouring buildings, which are located at a certain distance from railway.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.359-366
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• 2009

This paper aims for analyzing the vibration serviceability of train by simply expressing its vertical vibration when it passes a railway bridge. For this purpose, bridge-train transfer function was derived and bridge-train interaction analysis was performed by using the derived function. The bridge-train transfer function was developed with the assumption that train is a single mass-spring system, and bridge-train interaction analysis was performed on simple beams of KTX passenger car. The vertical acceleration signals of passenger cars obtained from bridge-train interaction analysis were compared with them of cars obtained from the bridge-train transfer function. As a result, it could be estimated to express the vertical vibration inside the passenger car required for vibration serviceability evaluation by using the vertical vibration of bridges obtained from moving load analysis. Therefore, it may be possible to evaluate the vibration serviceability of railway bridges considering bridge-train interaction effect.

• 한국정밀공학회지
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• 제21권10호
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• pp.170-179
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• 2004

A vibration model of powder transfer equipment is developed by the lumped parameter method. A Powder transfer equipment does surging motion, bouncing motion and pitching motion. Motion equation becomes decoupling and removed vibration exciting source about pitching motion, and therefore designers presented the optimum design plan to be able to do adjustment with motion trajectory of powder transfer equipment. That is, way for design to be able to do motion trajectory of powder transfer equipment through change of design element as installation position and direction of motor, driving speed, mass unbalance, stiffness coefficient and installation position of support coil spring is presented. The design results, powder transfer equipment were able to know that fatigue destruction does not occur, and the reason is because maximum stress working on a basket structure is more very than fatigue strength small.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.152-159
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• 1997

This paper presents a vibration analysis method of crank shaft of six cylinder internal combustion engine. For simple analysis journal, pin and arm parts were assumed to have uniform section. Transfer Matrix Method was used, considering branched part and coordinate transformation part. Natural frequencies, modeshapes and transfer functions of crank shaft were investigated based upon the Euler beam theory: It was shown that the calculated natural frequencies, modeshapes agree well with the existing paper results.