• 센서학회지
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• 제19권4호
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• pp.313-319
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• 2010

Vibration energy harvesting is an attractive technique for potential powering of low power devices such as wireless sensors and portable electronic applications. Most energy generator developed to date are single vibration frequency based, and while some efforts have been made to broaden the frequency range of energy harvester. In this work, The effect of energy harvesting were investigated at various vibration frequencies, vibration beams, vibration point and test masses. The maximum output voltage of the bimorph piezoelectric cantilever was shifted according to vibration point. Vibration frequency with maximum output voltage decreased with the increasing length of vibration beam and increasing test mass. The sample with vibration beam length 0.5 L generated a peak output voltage of 32 $V_{rms}$ and shows a 45 % increase in voltage output in comparison to the corresponding original bimorph. It was found that a piezoelectric bimorph has a possibility to be as the energy harvesting cantilever, which is successfully tuned over a vibration frequency range to enable a maximum harvesting energy.

• 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.

• 한국주조공학회지
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• 제22권5호
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• pp.238-244
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• 2002

Water and oil were completely synthesised with ultrasonic vibration energy irradiation. Pure Pb were added into Al melt during irradiated the ultrasonic vibration energy in 750. And the ultrasonic vibration energy was applied to Al-Pb melt to enhance the miscibility. Microstructural analysis, thermal analysis and X-ray diffraction analysis were carried out to evaluate the effect of the ultrasonic vibration energy on the castability and microstructural reliability. (1) Using the ultrasonic vibration energy irradiation, the complete mixing of water and oil was obtained. (2) The microstructure was refined by the application of ultrasonic vibration energy in Al-Pb alloys. (3) Relatively large Pb particles, $5{\mu}m$ were most distributed alone the grain boundaries with fine Pb particles evenly distributed in the matrix. (4) The solubility of Ph in Al-Pb alloys was increases up to 5% with the application of ultrasonic vibration energy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.385-392
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• 2001

Time-dependent frequency and energy of free vibration of the Spagetti problem, that is the axially moving continuum with time-varying length, are investigated. Exact expressions for the natural frequency and time-varying vibration energy are derived by dealing with traveling waves. When the string length is increased, the vibration period increases, but the free vibration energy varies as a function of both translating velocity and boundary velocity of the continuum. However, when the string undergoes retraction, the vibration energy increases with time, String tension together with non-zero instantaneous velocity at the moving boundary results in energy variation.

• 소음진동
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• 제9권5호
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• pp.906-913
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• 1999

Time-dependent period and energy of free vibration of a string, whose length varies with time at a constant rate, are investigated by a traveling wave method. When the string length is increased, the vibration period increase, but the free vibration energy decrease with time. However, when the string undergoes retraction, the vibration energy increases with time. String tension together with non-zero instantaneous velocity at the moving boundary results in energy variation. Analytical solutions by the traveling wave method are compared with previous results using the perturbation method and Kotera's approach.

• 한국수소및신에너지학회논문집
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• 제20권1호
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• pp.64-72
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• 2009

In order to convert efficiently vibration energy of a car tire wheel into electrical power by using piezoelectric materials, the design of the materials must be performed for the dynamic characteristics of the piezoelectric materials to be matched with them of the vibration energy sources well. An accelerometer was installed on the tire wheel with a slip ring to investigate the dynamic mode of the wheel as one of the vibration energy sources. During road test, the measurement on the vibration mode of the tire wheel was performed with variations of car speed and road condition. The experimental data were analyzed details for availability as a micro power source for wireless TPMS(Tire Pressure Monitoring System).

• Journal of Advanced Marine Engineering and Technology
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• 제37권6호
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• pp.596-602
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• 2013

기존의 진동에너지 하베스터는 한 주파수에서의 공진현상을 이용하여 에너지를 얻기 때문에 고정된 단일 주파수를 갖는 진동에너지로부터 전기에너지를 변환하는데 최적이지만 다양한 주파수를 포함하고 있는 파도와 같은 상하진동 에너지원으로부터 전기에너지를 얻는 데에는 한계가 있다. 본 논문에서는 이러한 단점을 해결하기위해 파도가 갖는 무한한 상하진동 에너지로부터 전기에너지를 얻는 광대역 진동에너지 하베스터를 연구하였다. 광대역 진동에너지 하베스터는 부양체와 진동에너지 하베스터가 각각 파도에너지가 갖는 중심주파수에서 공진이 발생되도록 구성되어있다. 그 결과 기존 공진을 이용한 진동에너지 하베스터는 한 주파수에서만 진동에너지를 전기에너지로 변환할 때 효율을 극대화할 수 있는 반면, 제안한 방법은 다양한 주파수를 포함하고 있는 파도에너지로부터 전기에너지로 변환할 때도 효율을 극대화 할 수 있는 장점을 가진다.

• 한국도로학회논문집
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• 제12권4호
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• pp.121-129
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• 2010

본 논문에서는 차량주행 시 교량에서 발생하는 진동에너지를 사회기반시설에 활용 가능한 전기에너지로 변환하는 진동력 발전시스템의 기초개념에 대해 연구하였다. 이 논문은 자기유도기술개념의 교량 진동력 발전 시스템에 대한 개념을 정립하고, 교량의 진동에너지를 전기에너지로 변환하는 진동력 발전장치를 제안하였다. 또한, 진동력 발전의 실 교량 적용성을 검토하기 위하여 제안한 진동력 발전장치를 용인신봉구역에 최근 건설된 차도교량에 직접 설치하여 실험함으로써, 본 논문에서 제안된 진동력 발전 장치의 발전성능과 교량의 상시진동을 이용한 진동력 발전의 적용 가능성을 확인하였다.

• 한국소음진동공학회논문집
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• 제24권2호
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• pp.87-92
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• 2014

이 논문에서는 기존 외팔보 빔 형상을 가진 진동 에너지 하베스터의 작동 주파수 범위를 공진 주파수 이후로 확장하기 위해 새로운 형태의 진동 에너지 하베스터가 제시되었다. 압전 재료를 사용한 기존 외팔보 빔 형상의 진동 에너지 하베스터에 레버형 반공진 시스템에서 발생하는 극점-영점 상쇄 기법을 적용하여 작동 주파수 영역을 확장하였다. 간단한 이론적 해석 및 실험을 통해 제안된 광역 압전 진동 에너지 하베스터의 실현 가능성을 검증하였다.

• Structural Engineering and Mechanics
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• 제43권3호
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• pp.395-410
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• 2012

The visualizing energy flow and control in vibrating stiffened plates with a cutout are studied using finite element method. The vibration intensity, vibration energy and strain energy distribution of stiffened plates with cutout at different excitation frequencies are calculated respectively and visualized for the various cases. The cases of different size and boundaries conditions of cutouts are also investigated. It is found that the cutout or opening completely changes the paths and distributions of the energy flow in stiffened plate. The magnitude of energy flow is significantly larger at the edges near the cutout boundary. The position of maximum strain energy distribution is not corresponding to the position of maximum vibrational energy. Furthermore, the energy-based control using constrained damping layer (CDL) for vibration suppression is also analyzed. According to the energy distribution maps, the CDL patches are applied to the locations that have higher energy distribution at the targeted mode of vibration. The energy-based CDL treatments have produced significant attenuation of the vibration energy and strain energy. The present energy visualization technique and energy-based CDL treatments can be extended to the vibration control of vehicles structures.