• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.145-149
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• 2000

In this paper, Firstly, it is shown that the bending mode vibration of check valve is comparatively large because resonance. Secondly in order to decrese the bending mode vibration of check valve, some practical dynamic vibration absorber have been developed and its effectiveness is investigated as installing it at the check valve of piping system practically.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.228-233
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• 2002

General modeling of a resonant shunting damper has been made from piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect. The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned electrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.328.2-328
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• 2002

General modeling of a resonant shunting damper has been made Iron piezoelectric sensor/actuator equation. It is found that an additional damping, which is augmented to a system, is generated by the shunt damping effect The transfer function of the tuned electrical absorber is derived for both series and parallel shunt circuit. The governing equations and associated boundary conditions are derived using Hamilton's Principle. The shunt voltage equation is also derived from the charge generated in PZT due to beam vibration. The frequency response function of the obtained mathematical model is compared with that of the tuned eledtrical absorber and experimental work. The vibration amplitude is reduced about 15 dB at targeted second mode frequency.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.1059-1066
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• 2011

The micro-perforated panel absorber(MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high(around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 추계학술대회 논문집
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• pp.178-185
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• 2011

The micro-perforated panel absorber (MPPA) is one of promising noise control elements because of its applicability to extreme environments where general porous materials cannot be used. Since the MPPA is inherently non-porous sound absorber, it can be a good candidate of acoustic protection system of a space launcher. The overall sound pressure level inside payload fairings of commercial launch vehicles is so high (around 140 dB OASPL) that the conventional linear impedance model cannot be directly applied to the design of the acoustic protection systems. In this paper an acoustic impedance models of a micro-perforated panel absorber at high sound pressure environment were reviewed and the use of the impedance on the practical design of MPPAs was addressed. The variation of absorption characteristics of MPPA was discussed according to the design parameters, e.g., perforation ratio, the minute hole diameter, the thickness of MPP and the incident sound pressure level.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.819-824
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• 2012

This paper presents the wideband vibration system of an electromagnetic vibration energy harvester that obtained electric power for wireless sensor applications from the ever-change vibrations of bridge. It is a system with two degree of freedom vibrations that are composed of two mass and two spring respectively. One system is housing mass and spring, the other is the magnetic mass and spring that is the vibration system construction's element of electromagnetic vibration energy harvester. In other words, it is called dynamic vibration absorber. This paper show that the ratio of housing mass to magnetic mass decides the bandwidth and the size of amplitude of magnetic mass in electromagnetic vibration energy harvester. Therefore, it is necessary to improve the efficiency of energy in electromagnetic vibration energy harvester for wireless sensor applications.

• 대한기계학회논문집
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• 제11권3호
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• pp.473-478
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• 1987

본 연구에서는 Newton법에 의한 수치해석을 이용하여 감쇠를 가진 진동계의 최적고유진동수비와 최적감쇠비를 구했으며, 비선형동흡진기가 부착된 진동계의 운동 방정식을 유도하여 조화밸런스법에 의한 진폭비를 산출해서 진폭비에 대한 비선형성의 영향 및 경성스프링과 연성스프링의 특성을 규명하였다.

• 한국소음진동공학회논문집
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• 제15권2호
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• pp.135-147
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• 2005

As automobile technology advances, a smoother ride with less noise is desired. In order to achieve these purposes, a study on the vibration and noise produced by a moving automobile was carried out and a model for tire vibration characteristics which influence the ride performance was developed. The model was verified through simulations and experiments. The developed model was then applied to a half car model and automobile vibrations were analyzed. The effects of tire design parameters on the automobile vibration energy were investigated. The results from laboratory and field tests confirm the validity of the analytical model. The 17-DOF half-car model was built to analyze automobile vibration. The characteristics of the nonlinear model for a shock absorber were applied to this model. The results from the present 17-DOF half car model incorporating the analytical tire model with tire design parameters, were compared with the 5-DOF half car model where the tire was modeled with linear springs. The results of the 17-DOF model are close to the experimental results. Using the 17-DOF model, the influence of tire design parameter were considered. According to the analysis results, the vibrations at seat/body/wheel were predicted by simulation and experiment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.805-810
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• 2004

The model is verified thorough simulations and experiments. And then the developed model is applied to a half car model and automobile vibrations are analyzed. The effects of tire design parameters on the automobile vibration energy are investigated. The results from laboratory and field tests confirm the validity of the analytical model. The 17-DOF half-car model is built to analyze the automobile vibration. The characteristics of the nonlinear model for a shock absorber are applied to this model. The results from the present 17-DOF half car model incorporating the analytical tire model with tire design parameters, are compared with a 5-DOF half car model where the tire is modeled with linear springs. The results of the 17-DOF model are closed to experimental results. Using the 17-DOF model, the influences of tire design parameter are considered. According to the results of analyses, the vibrations at seat/body/wheel are predicted by simulation and experiment.

• International Journal of Aeronautical and Space Sciences
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• 제12권4호
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• pp.331-345
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• 2011

In this paper, a visco-hysteretic vibration absorber (VA) is proposed to increase the flutter speed of an airfoil and enhance damping in the pre- and post-flutter regimes. The passive system consists of a parallel arrangement of a dashpot and a rateindependent hysteretic element, represented by the Bouc-Wen differential model. The equations of motion are obtained and various tools of linear and nonlinear dynamics are employed to study the effects of the visco-hysteretic VA in the pre- and postflutter ranges.