장력을 이용한 EYE-type 압전 발전기의 출력 특성

하용우,정성수,김나리,김명호,강신출,박태곤,Ha, Yong Woo,Jeong, Sung Su,Kim, Na Lee,Kim, Myong Ho,Kang, Shin Chul,Park, Tae Gone 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.8

Generating output characteristics of a EYE-type piezoelectric generator depending on ceramic size and materials of the elastic body were studied. EYE-type piezoelectric-generating device consist of the ceramic was attached between the both elastic body. piezoelectric-generating is that if the tension occurred at both ends of an elastic body, the piezoelectric effect occurs at ceramics through the form change of the elastic body. The structure of this EYE-type generator use various area. than a existing type generator, because the ceramic position of the directly force at does not apply. Resonance and output characteristics of the generator were analyzed by using FEM program. Generators were fabricated on the basis of analyzed results and attached on a frequency controllable vibrator to measure output characteristics. Also, the experimental results were compared with the simulated results. As a result, output characteristics of the generator increased depending on the increase in ceramic thickness. In case of increase in ceramic width, resonance frequency of the generator also decreased.

Generating Characteristics of an Eye-shaped Piezoelectric Harvester

하용우,정성수,Na-Lee Kim,Seong-Kyu Cheon,박태곤,송재성 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.2

In this paper, a newly designed piezoelectric harvester which generates electricity by using tensionson the device is proposed. The device is named as an eye-shaped harvester. The eye-shapedharvester consists of a rectangular ceramic and two elastic body plates are attached to each surfaceof the ceramic. If tensions are given at both ends of the elastic body, the tensions are changed topressures on the ceramic through a form change of the elastic body and the piezoelectric effect occursat the ceramic to generate electricity. Because of the structure of this eye-shaped generator if canbe easily in various places where tensions existing. This harvester has a relatively high durability,because the forces are not directly applied to the ceramic. The dependences of the generating outputcharacteristics of the eye-shaped piezoelectric harvester on the ceramic size and at the materials ofthe elastic body were studied. The resonance and the output characteristics of the generator wereanalyzed by using a finite-element –method program. Generators were fabricated on the basis ofthe analytical results and were attached to a frequency-controllable vibrator to measure the outputcharacteristics. Also, the experimental results were compared with the simulated results. Theoutput voltages of the generator were increase when ceramic is width was decreased. When theceramic’s length was decreased found to, the resonance frequency of the generator was decreased. For different materials of the elastic body, the highest voltage was obtained at the lowest resonancefrequency when brass was used.

소방시설 점검제도의 발전방안에 관한 연구

하용우(Ha, Yong-Woo),이수경(Lee, Su-Kyoung),박강서(Park, Kang-Seo) 한국화재소방학회 2006 한국화재소방학회 학술대회 논문집 Vol.2006 No.춘계

Synthesis of epoxy encapsulated organoclay nanocomposite latex via phase inversion emulsification and its gas barrier property

Viet Hung Pham,정진석,하용우,김상훈,정하택,정만용,고봉성,황영준 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

Waterborne epoxy–clay nanocomposites were prepared by encapsulation of organoclays in epoxy latexparticles via phase inversion emulsification. The organoclays were exfoliated in the epoxy backbonebefore compounding with a hardener and subsequently dispersing in water. The encapsulation of clayplatelets into the waterborne epoxy latex particle resulted in an exponential increase in particle size,from 5 to 10 times at a clay loading of only 1–2 wt%, respectively. The XRD patterns and TEM imagesshow that clay platelets were well intercalated and exfoliated in the epoxy matrix. The gas barrierperformance of the epoxy–clay nanocomposite strongly depended on the kind of organoclay. The bestoxygen barrier efficiency was approximately 14% at 2 wt% clay loading.

π-type 압전 하베스터의 출력 특성 연구

이병하,정성수,천성규,하용우,박태곤,Lee, Byeong-Ha,Jeong, Seong-Su,Cheon, Seong-Kyu,Ha, Yong-Woo,Park, Tae-Gone 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.1

Generating output characteristics of a ${\pi}$-type piezoelectric harvester depending on size of the ceramic and the elastic body were studied. The ${\pi}$-type piezoelectric harvester consists of a rectangular piezoelectric ceramic and a ${\pi}$ shaped elastic body. If the tensions is applied at both ends of an elastic body legs, the piezoelectric effect occurs at the ceramics through the form change of the elastic body. The structure of this ${\pi}$-type harvester can be used in a various area than an existing type generator, because it prevent from direct pressure to the ceramic. Generating characteristics of the harvester were analyzed by using finite element method program. The piezoelectric harvester was fabricated on the basis of analyzed results and attached on a frequency controllable vibrator to measure the output characteristics. And generating characteristics were defined by comparing analysis results and experimental results. The highest output voltage was obtained when the ceramic length, thickness were 20 mm, 0.5 mm in the analysis result. And experiment was performed by analysis results at low frequency region, output voltage was generated about 6 V.

탄성체 재질 변화에 따른 16각형 초음파모터의 토크 특성 연구

천성규,정성수,이병하,하용우,김명호,박태곤,Cheon, Seong-Kyu,Jeong, Seong-Su,Lee, Byung-Ha,Ha, Yong-Woo,Kim, Myong-Ho,Park, Tae-Gone 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.5

In this study, novel ultrasonic rotary motor of hexadecagon shape stator was proposed. Stator of the hexadecagon ultrasonic motor was composed of an elastic ring and ceramics. The elastic ring had sixteen sides and sixteen angular points. Eight ceramics were attached on the outer surface of the eight sides of the ring. When rotor of cylindrical shaft was inserted inside of the ring stator, central lines of the sixteen sides of the stator hold the shaft by the slight pressures(frictions). This slight pressure was a preload of the motor and it could be controlled by radius and thickness of the ring. When two sinusoidal voltages which have 90 degree phase difference were applied to each four ceramics, elliptical displacements of inner surface of the ring were obtained. These elliptical displacements of the inner surface rotated the shaft rotor through the frictions. The proposed hexadecagon ultrasonic motor was designed and analyzed by using the finite element method (FEM), depending on materials of the elastic ring. Based on the FEM results, one model of motor which showed maximum displacement at contact points was chosen and fabricated. And characteristics of the motor were compared with simulated results. When the motor was fabricated with these results, EL20ET0.5CT0.5CW2 model showed 115[rpm] speed about input voltage of 60[Vrms] at 65.6[kHz]. And the maximum torque of 6[gfcm] was obtained. From these results, the hexadecagon shaped ultrasonic motor can be used to actuator for optical device which needs detailed position control. Also it can be used to medical and portable device by reducing size and weight.

교량의 무선센서노드 구동을 위한 압전 하베스터의 특성연구

이병하,정성수,천성규,하용우,박태곤 한국물리학회 2015 새물리 Vol.65 No.8

Electricity generation of a newly-proposed piezoelectric harvester for driving wireless sensors to monitor a bridge was studied. There are various security sensors on a bridge, and those require relatively lower electrical power than other lamps or sign posts. As an electric source for the sensors, a piezoelectric harvester which converts the mechanical vibrations of the bridge to electrical power, instead of a battery, was studied. The harvester, which had a low-frequency region, was analyzed by using the finite element method program ANSYS. The harvester was fabricated on the basis of the FEM result, and the experiment was conducted under conditions similar to those used for the simulation. The generating characteristics were verified by using the FEM and the experiment. The dependences of the output current and power on the load resistance were measured and by comparing our result to the power consumptions of other sensors, we identified the possibility of using this newly-proposed piezoelectric energy harvester for driving wireless sensors. 교량 모니터링 무선센서노드를 구동하기 위해 새로 제안된 압전 하베스터의 출력특성을 연구 하였다. 교량에는 다양한 안전 센서가 있으며 그 센서들은 전등과 표지판 이외의 상대적으로 낮은 전력을 필요로 한다. 센서의 전원으로써, 배터리 대신에 교량의 기계적 진동을 전력으로 변환해주는 압전 하베스터를 연구 하였다. 교량의 공진 주파수 영역을 확인했고, 동일한 주파수 영역에서 하베스터는 유한요소해석 프로그램인 ANSYS를 사용하여 분석하였다. 압전 하베스터는는 유한요소해석 결과를 바탕으로 제작 하였고 교량의 유사한 환경에서 실험을 실시하였다. 출력 특성은 유한요소해석과 실험을 통해 확인하였고, 전력 변환 및 저장을 통해 무선센서노드의 소비 전력을 비교함으로써, 무선 센서의 구동 가능성을 확인하였다.