• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.4
• /
• pp.811-818
• /
• 1992

The sensor technology has becoming emerging area as the automation process in industry requires higher productivity, better quality, and the reliability. In this research, the dynamic measuring sensor such as piezoelectric accelerometers has been developed. Especially, the research concentrates on a design methodology, an analysis of the structural characteristics, and a method of the performance evaluation. The fabricated piezoelectric accelerometers show that the performance characteristics is better than commercial products available in the current market.

• The Journal of the Acoustical Society of Korea
• /
• v.15 no.1
• /
• pp.10-16
• /
• 1996

Ultrasonic motor is a motor driven by the stator via frictional contact forces generated from ultrasonic vibration of piezoelectric elements. In order to control the ultrasonic motor, it is essential to measure accurately the motor characteristics with respect to driving parameters such as frequency, voltage, phase difference and duty ratio of the driving signals. In this paper, a PC-interfaced evaluation device is developed, and the characteristic curves of the fabricated ultrasonic motor are measured with those parameters. All driving parameters are processed digitally. The developed evaluation device can facilitate charateristics measurements effectively, and provide a base for digital control of the ultrasonic motor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.37-38
• /
• 2006

본 연구에서는 압전체의 횡 진동모드를 이용한 압전 초음파 진동자를 설계 분석하였다. 이전의 란쥬반 진동자는 진동을 얻기 위하여, 복수의 원판 또는 사각판 형태의 압전 세라믹을 서로 반대 방향으로 분극하여 마주 보도록 설치한 후 전기적으로 병렬로 연결하고 상단 및 하단에 금속부을 부착하여 전체를 볼트로 조인 복잡한 구조와 큰 출력 파워를 갚는 반면, 본 연구에서는 판상형의 압전소자와 일체형 금속진동체를 이용하여 기계적 출력 파워 조절이 용이한 구조의 압전 진동자를 고안하여, 압전진동자의 횡 진동 모드를 이용함으로써 신뢰성과 정확도가 높고 진동효율이 최대가 되도록 설계하였다. 설계 개발된 압전 진동자는 진동의 크기 조절이 용이하여 일반 진동자 뿐 만 아니라, 외과 및 안과 수술에 있어서 인체조직이나 각막상피의 활성화를 유지한 상태에서 안전하게 절개 및 분리 시술용 진동자로 사용 할 수 있는 이점이있다. 압전 진동자는 유한요소법 시뮬레이션 프로그램 (ATILA 5.2.4)을 이용하여 설계를 하였으며 압전소자의 두께는 각각 0.2 mm, 0.5 mm로 제작하여 시뮬레이션 결과와 제작된 샘플의 특성을 비교하였고, 변위측정은 칼날을 결합 한 상태에서 공진 주파수대역 부근 주파수별로 측정 비교하였다.

• Electrical & Electronic Materials
• /
• v.25 no.4
• /
• pp.4-9
• /
• 2012

• Korean Journal of Materials Research
• /
• v.1 no.2
• /
• pp.105-112
• /
• 1991

In PLZT system, a new type of material for piezoelectric actuator was developed and its properties were investigated. This material consists of three layers : a piezoelectric ceramic layer, an interlayer which composition changes gradually, and another piezoelectric layer. This kind of materials is called functionally Gradient Materials(FGM). The composition of these layers were selected from the $(Pb,\;La)(Zr,\;TiO_3$ system through the concept of materials design. Sintered FGM at $1300^{\circ}C$, 2hr has an interlayer of about $20\mu\textrm{m}$ with no distorted damage. Dielectric and piezoelectic properties of FGM show intervalues of each side composition. The strain-voltage characteristics in FGM system was improved comparison with any single composition. Especially, the FGMs were fabricated which has high piezoelectric-low dielectric composition and low piezoelectric-high dielectric composition. The properties of both FGMs were significantly improved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.327-328
• /
• 2006

본 연구에서는 0-3 타입의 압전 세라믹 - 고분자 복합소재를 제조하기 위해서 $Pb(Zr_{0.54}Ti_{0.48})O_3$ + 0.2 wt% $Cr_2O_3$ + 1 wt% $Nb_2O_5$ 조성을 기본 조성으로 하여, 세라믹-고분자 첨가량에 따른 복합소재의 전기적 특성과 여러 분극조건, 즉 분극온도, 분극시간, 분극전압 변화에 의한 압전 특성을 고찰하였다. 세라믹 첨가비율이 증가함에 따라 유전상수와 압전상수($d_{33}$)는 증가하였으며, 전압상수($g_{33}$)는 급격히 감소하는 경향을 보였으며, 분극시간과 분극전압도 전기적 특성에 영향을 주는 것을 확인하였다. 분극전압 5KV 인가한 고분자 15% 첨가한 복합 소재에서 유전상수 13, 압전상수 $d_{33}$ 23(${\ast}10^{-12}C/N$), 전압상수 $g_{33}$ 170($10^{-3}v.m/N$)의 우수한 특성을 나타내었다.

• Composites Research
• /
• v.34 no.6
• /
• pp.357-372
• /
• 2021

The energy harvesting device is known to be promising as an alternative to solve the resource shortage caused by the depletion of petroleum resources. In order to overcome the limitations (environmental pollution and low mechanical properties) of piezoelectric elements capable of converting mechanical motion into electrical energy, many studies have been conducted on a polymer matrix-based composite piezoelectric energy harvesting device. In this paper, the output performance and related applications of the reported piezoelectric composites are reviewed based on the applied materials and processes. As for the piezoelectric fillers, zinc oxide, which is advantageous in terms of eco-friendliness, biocompatibility, and flexibility, as well as ceramic fillers based on lead zirconate titanate and barium titanate, were reviewed. The polymer matrix was classified into piezoelectric polymers composed of polyvinylidene fluoride and copolymers, and flexible polymers based on epoxy and polydimethylsiloxane, to discuss piezoelectric synergy of composite materials and improvement of piezoelectric output by high external force application, respectively. In addition, the effect of improving the conductivity or the mechanical properties of composite material by the application of a metal or carbon-based secondary filler on the output performance of the piezoelectric harvesting device was explained in terms of the structure of the composite material. Composite material-based piezoelectric harvesting devices, which can be applied to small electronic devices, smart sensors, and medicine with improved performance, can provide potential insights as a power source for wireless electronic devices expected to be encountered in future daily life.

• Journal of Satellite, Information and Communications
• /
• v.7 no.3
• /
• pp.22-25
• /
• 2012

In this paper, we proposed a method of the resonant frequency shift of a microstrip patch antenna using $LiNbO_3$, PVDF and FR-4 substrates. We designed and analyzed from these parametars optimized using Ensemble V 7.0 of the simulation tool. We observed the resonant frequency by DC appled electric field in a microstrip patch antenna. When $LiNbO_3$ substrate were applied from -300 to 300 V/mm, we obtained the resonant frequency shift of maximum 29 MHz. The microstrip patch antenna with PVDF (poly vinylidene fluoride) substrate, we obtained the resonant frequency shift of maximum 17 MHz at frequency 6 GHz. but when Epoxy FR-4 substrates used, the resonant frequency does not changed. This results showed the resonant frequency shift without physical strains in a microstrip patch antenna.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.7
• /
• pp.1645-1652
• /
• 2013

In this paper, a new piezoelectric transducer for high performance ultrasonic flaw detector used in non-destructive test (NDT) is implemented. Here, the goals for some major characteristics such as piezoelectric strain constant and electro-mechanical coupling factor are fixed in advanced. Then, the parameters obtained by finite element analysis (FEA) are exploited to design and implement the piezoelectric transducer. As a result of experiments using manufactured samples, it is proved that the new PZT ceramics satisfy the goals very well. It has much improved impedance characteristic at the resonant frequency and generation of ultrasonic signals. In addition, ultrasonic flaw detector with the new transducer provides increased flaw detecting gain than the conventional one. Thus, it is considered that the new flaw detector contributes significantly to improve reliability of the NDT.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.11
• /
• pp.963-970
• /
• 2015

In this study, the pressurization characteristics of the small piezoelectric hydraulic pump for a brake system has been analyzed through modeling the full hydraulic pump components; the pump chamber, check valve, pump load, pump drive controller etc. To analyze the pressurization characteristics, the process of charging pressure in the chamber with stacked-layer piezoelectric actuator were firstly modeled. Secondly, the flow coefficient of the check valve in terms of valve opening has been calculated after computational fluid dynamics analysis, such as the pressure distribution around check valve and the flow rate, was conducted. Also the pump driving controller, which controls the input voltage to the actuator, was designed to make the load pressure follow the input pressure command. The simulation results find that it takes about 0.03ms to reach the operating load pressure required for the braking system. The simulation result was also verified through comparison to the result of the pump performance test.