• 제목/요약/키워드: Piezoelectric layer

검색결과 353건 처리시간 0.029초

브레이크용 소형 압전유압펌프 가압 동특성 해석 (On the Pressurization Characteristics of Small Piezoelectric Hydraulic Pump for Brake System)

  • 정민지;황재혁;배재성;권준용
    • 한국항공우주학회지
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    • 제43권11호
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    • pp.963-970
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    • 2015
  • 본 연구에서는 압전유압펌프의 챔버부, 체크밸브, 부하, 펌프구동제어기 등 유압펌프 전체 구성품의 해석 모델링을 통하여 브레이크용 소형 압전유압펌프의 가압 동특성을 해석하였다. 가압 동특성을 해석하기 위해 먼저 적층형 압전작동기가 챔버내에서 압력을 형성하는 과정을 모델링하였다. 체크밸브 개도에 따른 유량계수 식을 얻기 위해, 유한요소코드 해석을 통해 체크밸브 압력분포 및 유동결과를 얻은 후 체크밸브 유량계수식을 커브 피팅으로 유도하였다. 또한 부하압력을 피드백 받아 작동기 입력전압을 제어하여 부하압력이 입력명령 압력을 잘 추종하도록 펌프구동제어기를 설계하였다. 시뮬레이션 결과 브레이크 작동에 필요한 정상작동압력까지 도달하는데 걸리는 시간은 약 0.03ms 정도이다. 본 연구에서 얻어진 해석 시뮬레이션 결과는 실제 실험결과와 비교를 통해 타당성을 검증하였다.

압전층의 2단 증착법을 이용한 체적 음향파 박막형 공진기의 제작과 성능향상에 관한 연구 (A Study of the Fabrication and Enhancement of Film Bulk Acoustic Wave Resonator using Two-Step Deposition Method of Piezoelectric Layer)

  • 박성현;추순남;이능헌
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제54권7호
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    • pp.308-314
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    • 2005
  • The 2 GHz film bulk acoustic wave resonator(FBAR), one of the most necessary device of the next generation mobile communication system, consisted of solidly mounted resonator(SMR) structure using Brags reflector, was researched in this paper The FBAR applied SiO$_{2}$ and W had large difference of the acoustic impedance to reflector Al to electrode and ZnO to piezoelectric layer. Specially, the FBAR applied the two-step deposition method to improve the c-axis orientation and increase reproducibility of the fabrication device had good performance. The electrical properties of plasma such as impedance, resistance, reactance, $V_{pp},\;I{pp}$, VSWR and phase difference of voltage and current, was analyzed and measured by RF sensor with the variable experiment process factors such as gas ratio, RF power and base vacuum level about concerning the thickness, c-axis orientation, adhesion and roughness. The FBAR device about the optimum condition resulted reflection loss(S$_{11}$) of -17 dB, resonance frequency of 1.93 GHz, electric-mechanical coefficient(k$_{eff}$) of 2.38 $\%$ and Qualify factor of 580. It was seen better qualify than the common dielectric filter at present and expected on business to the filter device of 2 GHz bandwidth with the MMIC technology.

혈관 내부 진단용 원형 배열 초음파 트랜스듀서에 대한 연구 (A Study on an Ultrasonic Circular Array Transducer for Intra-vascular Ultra-sound Diagnosis)

  • 김희원;이수성;노용래
    • 한국음향학회지
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    • 제22권4호
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    • pp.329-336
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    • 2003
  • 본 연구에서는 혈관 내부 조영용으로 사용될 수 있는 원형 배열 초음파 트랜스듀서를 설계하고 제작하였다. 트랜스듀서는 알루미나 튜브 위에 부착된 32개의 압전 소자와 전면 절연층, 고분자 후면층으로 구성된다. 우선 트랜스듀서의 방사특성 해석을 통해 원주방향으로 무지향성을 가지는 원형 배열 구조를 설계하였다. 압전소자로는 2-2형 압전복합재료를 채택하였다. 설계 결과에 따라 직경 3㎜의 원형 배열 트랜스듀서를 제작하고 그 음향특성을 측정하였으며, 측정 결과는 설계치와 잘 일치하였다. 실험적으로 확인된 무지향성은 본트랜스듀서의 IVUS (Intra-Vascular Ultra-Sound)센서로의 적용가능성을 확인시켜 주는 것이었다.

압전 복합재료 작동기 LIPCA를 이용한 보의 진동 제어 (Vibration Control of Beam using Piezoceramic Composite Actuator LIPCA)

  • 아리프수하리요노;구남서;박훈철;윤광준
    • 한국군사과학기술학회지
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    • 제8권4호
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    • pp.130-135
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    • 2005
  • This paper presents application possibility of Lightweight Piezoceramic Composite Actuator(LIPCA) to suppress vibration of dynamic structures as an actuator. LIPCA is composed of a piezoelectric layer, a carbon/epoxy layer and glass/epoxy layers. When compared to the bare piezoelectric ceramic(PZT), LIPCA has advantages such as high performance, durability and reliability. In this study, performances of LIPCA have been estimated in an active vibration control system. Experiments were performed on an aluminum beam with cantilever configuration. In this test, strain gages and single LIPCA are attached on the aluminum beam with epoxy resin. Digital ON-OFF control algorithm is applied into the system to exhibit performance of LIPCA as actuator in active vibration control system. First, we performed static actuation test of bare PZT and LIPCA in order to show the superiority of LIPCA. Secondly, we carried out beam vibration control test using LIPCA. The results showed LIPCA could suppress free vibration of the aluminum beam, which means that LIPCA can be applied as an actuator to control vibration of dynamic structures.

Micro to Nano-scale Electrohydrodynamic Nano-Inkjet Printing for Printed Electronics: Fundamentals and Solar Cell Applications

  • 변도영
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.3.2-3.2
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    • 2011
  • In recent years, inkjet printing technology has received significant attention as a micro/nanofabrication technique for flexible printing of electronic circuits and solar cells, as well for biomaterial patterning. It eliminates the need for physical masks, causes fewer environment problems, lowers fabrication costs, and offers good layer-to-layer registration. To fulfill the requirements for use in the above applications, however, the inkjet system must meet certain criteria such as high frequency jetting, uniform droplet size, high density nozzle array, etc. Existing inkjet devices are either based on thermal bubbles or piezoelectric pumping; they have several drawbacks for flexible printing. For instance, thermal bubble jetting has limitations in terms of size and density of the nozzle array as well as the ejection frequency. Piezoelectric based devices suffer from poor pumping energy in addition to inadequate ejection frequency. Recently, an electrohydrodynamic (EHD) printing technique has been suggested and proposed as an alternative to thermal bubble or piezoelectric devices. In EHD jetting, a liquid (ink) is pumped through a nozzle and a strong electric field is applied between the nozzle and an extractor plate, which induce charges at the surfaces of the liquid meniscus. This electric field creates an electric stress that stretches the meniscus in the direction of the electric field. Once the electric field force is larger than the surface tension force, a liquid droplet is formed. An EHD inkjet head can produce droplets smaller than the size of the nozzle that produce them. Furthermore, the EHD nano-inkjet can eject high viscosity liquid through the nozzle forming tiny structures. These unique features distinguish EHD printing from conventional methods for sub-micron resolution printing. In this presentation, I will introduce the recent research results regarding the EHD nano-inkjet and the printing system, which has been applied to solar cell or thin film transistor applications.

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나노스템프 구동용 중공형 압전액추에이터 기본특성에 관한 연구 (Study on Basic Characteristics of Hollow Piezoelectric Actuator for Driving Nanoscale Stamp)

  • 박중호;이후승;이재종;윤소남;함영복;장성철
    • 대한기계학회논문집A
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    • 제35권9호
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    • pp.1015-1020
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    • 2011
  • 최근, MEMS/NEMS 기술을 이용하여 기능성 나노 구조물을 제작하기 위한 공정기술 중에, 마스터 스템프에 형성된 나노패턴을 웨이퍼 등에 복제할 수 있는 나노임프린트 리소그래피 기술이 활발히 연구되고 있다. 본 연구에서는 기존 멀티헤드방식 나노임프린팅 장비에서 사용되던 전동모터를 대신하여 플렉셔 메커니즘과 결합된 나노스템프를 구동하기 위한 사각 형상의 중공형 압전액추에이터를 설계, 제작하였으며, 제조공정이 다른 각각의 시제품의 변위, 발생력 및 응답특성에 관한 검토를 수행한다. 또한, 압전 액추에이터의 변위제어에 대한 제어수법을 간단히 소개하였으며, 제작한 프로토타입의 PI제어기에 의한 변위 제어결과를 소개한다.

P(VDF-TrFE-CFE)를 이용한 초소형 압전 적층형 진동 출력 소자의 제작 (Fabrication of Ultra-Small Multi-Layer Piezoelectric Vibrational Device Using P(VDF-TrFE-CFE))

  • 조성우;;김재규;류정재;김윤정;김혜진;박강호;홍승범
    • 한국전기전자재료학회논문지
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    • 제32권2호
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    • pp.157-160
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    • 2019
  • P(VDF-TrFE-CFE) (Poly (vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)), which exhibits a high electrostriction of about 7%, can transmit tactile output as vibration or displacement. In this study, we investigated the applicability of P(VDF-TrFE-CFE) to wearable piezoelectric actuators. The P(VDF-TrFE-CFE) layers were deposited through spin-coating, and interspaced with patterned Ag electrodes to fabricate a two-layer $3.5mm{\times}3.5mm$ device. This layered structure was designed and fabricated to increase the output and displacement of the actuator at low driving voltages. In addition, a laser vibrometer and piezoelectric force microscope were used to analyze the device's vibration characteristics over the range of ~200~4,200 Hz. The on-off characteristics were confirmed at a frequency of 40 Hz.

Vibration Analysis of the Active Multi-Layer Beams by Using Spectrally Formulated Exact Natural Modes

  • Lee, Usik;Kim, Joohong;Andrew Y. T. Leung
    • Journal of Mechanical Science and Technology
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    • 제15권2호
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    • pp.199-209
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    • 2001
  • Modal analysis method (MAM) is introduced for the fully coupled structural dynamic problems. In this paper, the beam with active constrained layered damping (ACLD) treatment is considered as a representative problem. The ACLD beam consists of a viscoelastic layer that is sandwiched between the base beam structure and an active piezoelectric layer. The exact damped natural modes are spectrally formulated from a set of fully coupled dynamic equations of motion. The orthogonality property of the exact damped natural modes is then derived in a closed form to complete the modal analysis method. The accuracy of the present MAM is evaluated through some illustrative examples: the dynamic characteristics obtained by the present MAM are compared with the results by spectral element method (SEM) and finite element method (FEM). It is numerically proved that MAM solutions become identical to the accurate SEM solutions as the number of exact natural used in MAM is increased.

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Analysis and active control for wind induced vibration of beam with ACLD patch

  • Li, Jinqiang;Narita, Yoshihiro
    • Wind and Structures
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    • 제17권4호
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    • pp.399-417
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    • 2013
  • The structural vibration suppression with active constrained layer damping (ACLD) was widely studied recently. However, the literature seldom concerned with the vibration control on flow-induced vibration using active constrained layer. In this paper the wind induced vibration of cantilevered beam is analyzed and suppressed by using random theory together with a velocity feedback control strategy. The piezoelectric material and frequency dependent viscoelastic layer are used to achieve effective active damping in the vibration control. The transverse displacement and velocity in time and frequency domains, as well as the power spectral density and the mean-square value of the transverse displacement and velocity, are formulated under wind pressure at variable control gain. It is observed from the numerical results that the wind induced vibration can be significantly suppressed by using a small outside active voltage on the constrained layer.

1×1 mm2 대면적 녹색 LED의 전기 광학적 특성 분석 (Electro-Optical Characteristics and Analysis of 1×1 mm2 Large-Area InGaN/GaN Green LED)

  • 장이운;조동섭;전주원;안태영;박민주;안병준;송정훈;곽준섭;김진수;이인환;안행근
    • 한국진공학회지
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    • 제20권4호
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    • pp.288-293
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    • 2011
  • 본 논문은 InGaN/GaN 다중양자우물 구조를 가지는 녹색 발광다이오드의 활성층 내 인듐(In) 조성비와 piezoelectric field에 대한 전계 흡수 현상을 연구하였다. 활성층 내 결정학적 성질과 In 조성비는 double crystal X-ray diffraction 측정으로 분석하였으며, $1{\times}1\;mm^2$ 대면적 칩을 제작하여 발광특성을 조사하였다. 또한, 활성층 내 piezoelectric field는 electro-reflectance spectroscopy로부터 측정한 compensation voltage를 이용해 계산하였고, 인가전압에 따른 photocurrent의 변화를 측정함으로써 녹색 발광 소자의 전기 광학적 특성을 분석하였다.