• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.863-868
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• 2001

It is necessary to design th anti-vibration system of precision machinery for a sound operation and a quality assurance. However, in general. the allowable vibration limit is not well known. In the paper, the vibration criteria for foundation of vibration sensitive machinery is proposed and anti-vibration system is designed by using vibration measurement results of foundation. Also, the F.E. analysis is performed to verify the effectiveness of a designed anti-vibration system and to determine allowable dynamic load of machinery

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.56-59
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• 2003

As the slab is longer and lighter, it is more sensitive to the external force so that the vibration of slab and noise induced by the slab vibration is bigger than expected in normal slab. The purpose of this study is to investigate how the dynamic characteristic of slab is different from the normal slab through the system identification and tn evaluate the vibration control performance when the damper system is installed. Finally, we was trying to understand by what mechanism the slab noise is induced from the slab vibration. The relationship between the vibration and the noise of slab is shown by the numerical simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.706-711
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• 2001

A dynamic vibration absorber(DVA) is developed to reduce the excessive focusing vibration of an optical disc drive(ODD) originated from the resonance of an wobble disc. We design the material properties of the DVA by FEM model such as Young's modules, damping coefficient, shapes and dimensions, analyze its dynamic characteristics and provide its design guide line for suppressing the vibration of an optical disc drive. To examine the performance. of the DVA, the vibration of the wobble disc and the feeding system is measured by using a laser vibrometer and the noise level is checked by using microphone. The result shows that the proposed DVA reduces the vibration and. the noise in an optical disc drive.

• 소음진동
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• 제10권3호
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• pp.493-499
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• 2000

Structural vibration analysis of the stationary power plant system employing a large two-stroke low speed diesel engine is performed to verify that the vibration characteristics of the system meet design requirements, The system consists of the diesel engine generator and concrete foundation including pile and soil. The system is modeled in the form of a mass-elastic system of 5 degrees of freedom for vibration analysis. Excitation moments and dynamic parameters including engine body stiffness soil stiffness and damping are identified for the analysis, Results of structural vibration analysis of the system are presented and compared with measurements in this paper.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.465-472
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• 2008

An automotive windshield wiper system is modeled mainly for vibration analysis purpose. The model is composed of solid links, ideal joints, imperfect joints to simulate unavoidable manufacturing defects and bushings having stiffness, contact between a wiper blade and a wind screen glass, friction, a spring and an actuator. Main stream of wiper dynamics analysis has been obtaining a closed form of system of equations using Newton's or Lagrange's formula and doing a numerical simulation study to understand and predict the behavior of it. However, the modeling process is complex since a wiper system is of multibody and a contact problem occurs. When imperfection, such as dead zone of a joint and stiffness of a rubber bushing, should be included, the added complexity makes the modeling difficult. Since the imperfection is understood as main cause of problematic vibration, the dynamics model of a wiper system aiming vibration analysis should include such unavoidable manufacturing defects in the model. An open form of dynamic model of a automotive windshield wiper system with imperfect joints using a commercial software is obtained and a simulation analyssis is conducted for vibration reduction study.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1719-1724
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• 2010

In the areas susceptible to vibration and noise induced by railway traffic such as downtown area and stations under railway lines, the vibration and the structure-borne noise can be solved by floating slab track system separating the entire track structure from its sub-structure using anti-vibration mat or springs. In other countries, the core technologies for vibration-proof design and vibration isolator - one of key components - have been developed and many installation experiences have been accumulated. However, in Korea, since the design technology of system and components are not yet developed, the foreign systems are being introduced without any adjustment. Thus, in this study, the vibration isolator has been developed and its performance are investigated by the dynamic analysis of a station structure under railways lines and the floating slab track system. For this purpose, the loads transferred from the vibration isolator of the floating slab track were evaluated by train running simulation considering vehicle-track interaction, and then the dynamic analysis of station structure subjected to these loads was performed. The dynamic analysis results show that the proposed floating slab track can reduce the vibration of structure by about 25dB compared with that in conventional ballast track without floating system.

• 한국소음진동공학회논문집
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• 제26권6_spc호
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• pp.721-728
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• 2016

The combined rotational and translational dynamic vibration absorbers (DVA) with no dampers for the beam vibration control can effectively isolate the vibration within the external excitation force region. This paper investigates the damping efficacy for the combined rotational and translational dynamic vibration absorbers to impose some robustness to the DVA system for the excitation force frequency variation. The beam is assumed to be subjected to a concentrated harmonic excitation force. The solution to the problem is found based on Galerkin method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.329-334
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• 2002

Preliminary test for the design and construction of a tuned dynamic absorber is a conducted. Proposed tuned dynamic absorber is a cantilevered beam type, and is supposed to adjust its natural frequency according to the changing operation condition of the primary system. The modal mass of the dynamic absorber is the easiest to control, therefore, the position of the attached mass of the dynamic absorber is considered as the main design parameter of the absorber. The effect of the dynamic absorber is experimentally verified under various operation conditions of the primary system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.556-559
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• 2007

The notion of linearity is fundamental in science and engineering. Much of system and control theory is based on the analysis of linear system, which does not care whether it is nonlinear and complex. The dynamic programming is one of concerned technology when users are interested in choosing best choice from system operation for nonlinear or dynamic system‘s performance and control problem. In this paper, we will introduce the dynamic programming which is based on discrete system. When the discrete system is constructed with discrete state, transfer between states, and the event to induct transfer, the discrete system can describe the system operation as dynamic situation or symbolically at the logical point of view. We will introduce technologies which are related with controllable of Controlled Markov Chain as shown example of simple game. The dynamic programming will be able to apply to optimal control part which has adaptable performance in the discrete system.

• 한국기계가공학회지
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• 제14권6호
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• pp.27-34
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• 2015

Dynamic vibration absorbers are widely used in machinery, buildings, and structures, including bridges. Two cases of their usage are considered in this paper. One is a simply supported beam subjected to either a moving force or a sequence of moving forces, which simulates a train-bridge interaction problem. The other is a case where a primary system is mounted on a base that is not grounded and is excited by an external force. The conditions that the dynamic vibration absorbers must meet in these cases are found and compared to those for usual cases where bases of primary systems are grounded.