• Title/Summary/Keyword: piezoceramic

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Design and Displacement Analysis by ANSYS of Ultrasonic Linear Motor (초음파 리니어 모터의 설계와 ANSYS에 의한 변위량해석)

  • 김태열;강도원;김범진;박태곤;김명호
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.300-302
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    • 1999
  • The standing waves of the fourth bending mode of vibration and first longitudinal mode of vibrator were utilized to construct a ultrasonic linear motor. The geometrical dimensions of the vibrator were determined by Euler-Bernoulli theoty. FEM(finite element method) employed to calculate the vibration mode of the metal-piezoceramic composite thin plate vibrator. ANSYS was used to design positions of the projections and calculate displacement of vibrator.

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Experiment on Vibration control of Beam using Active Constrained Layer Damping Treatment (능동구속감쇠 기법을 이용한 보의 진동제어 실험)

  • Choi, Jin-Young;Kang, Young-Kyu;Kim, Jae-Hwan;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.262-267
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    • 2000
  • The flexural vibration of aluminum beams with active and passive constrained-layer damping has been investigated experimentally to design structure with maximum possible damping capacity. Piezoelectric film is used as sensor and piezoceramic as actuator for negative velocity feedback control. This paper shows the effectiveness of active constrained-layer damping treatment through experiment, and we have carried out an experiment to study effect of beam thickness.

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Design of a Multimode Piezoelectric Spherical Vector Sensor for a Cardioid Beam Pattern (심장형 빔 패턴을 위한 다중모드 압전 구형 벡터센서 설계)

  • Lim, Youngsub;Lee, Jaeyoung;Joh, Cheeyoung;Seo, Heeseon;Roh, Yongrae
    • The Journal of the Acoustical Society of Korea
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    • v.32 no.1
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    • pp.32-42
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    • 2013
  • Typical underwater piezoelectric spherical sensors are omni-directional, thus can measure the scalar quantity sound-pressure-magnitude only with the limitation not being able to measure the direction of the incoming wave. This paper proposes a method to simultaneously measure both the magnitude and direction of the sound wave with the spherical sensor. The method divides the piezoceramic sphere of the sensor into eight elements, and distinguishes the magnitude and direction of the sound pressure by combining the output voltage of the elements in a particular manner. Further, through the analysis of the sensitivity variation in relation to the structural parameters like radius and thickness of the piezoceramic sphere, we have suggested the way to improve the sensitivity of the vector sensor.

Development of Smart Active Layer Sensor (I) : Theory and Concept Study (스마트 능동 레이어 센서 개발 (I): 이론 및 개념 연구)

  • Yoon, Dong-Jin;Lee, Young-Sup;Kwon, Jae-Hwa;Lee, Sang-Il
    • Journal of the Korean Society for Nondestructive Testing
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    • v.24 no.5
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    • pp.465-475
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    • 2004
  • This paper is the first part of the study on the development of a smart active layer (SAL) sensor, which consists of two parts. In this first part, the theory and concept of the SAL sensor is investigated, which is designed for the detection of elastic waves caused by internal cracks and damages in structures. For the development SAL sensor, (i) the basic theory of elastic waves was studied, (ii) the feasible study of the SAL as an elastic waves detection sensor using the finite element analysis (FEA) with respect to a piezoceramic disc was performed. (iii) the comparison of performances between some piezoceramic sensors and a commercial acoustic emission (AE) sensor was accomplished to ensure the applicability by the experimental means, such as a pencil lead break test. Also, the conceptional study for the SAL sensor, which can be utilized for the effective detection and locating of defects by the arrangement of regularly distributed sensors, was discussed.

Quantitative Assessment of the Fastening Condition and the Crack Size with Using Piezoceramic(PZT) Sensors (압전소자를 이용한 볼트토크 및 크랙의 정량적평가에 관한 연구)

  • Hong, Dong-Pyo;Hong, Yong;Wang, Gao-Ping;Han, Byeong-Hee;Kim, Young-Moon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.603-606
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    • 2006
  • We present a study on the development of a practical and quantitative technique for the assessment of the structural health condition with using piezoceramic(PZT) sensors. The electro-impedance-based technique with the PZT patches is very sensitive for evaluation of the incipient and small damage in a high frequency range, and however the commonly traditional modal analysis method is effective only for considerably larger damages in low frequency range. The paper presents the technique in detecting and characterizing real-time damage on the specimen that is an aluminum plate fastened with bolts and nuts by different torques and as well a plate with a crack. By using the special arrangement of the PZT sensors, the required longitudinal wave is generated through the specimen. A large number of experiments are conducted and the different conditions of the specimens, i.e. the location and extent of loosening bolts, and the plate with a crack are simulated. respectively. Since fixing and loosening the loosened bolt is controlled by a torque wrench, we can control exactly the experiment of the different torques. Compared with the simulated healthy condition, we can find whether or not there is a damage in the specimen with using an impedance analyzer with the PZT sensors. Several indices are discussed and used for assessing the different simulated damages. As for the location of bolt loosening, the RMSD is found to be the most appropriate index for numerical assessment and as well the RMSD shows strongly linear relationship for assessing the extent of the bolt loosening, and the frequency peak shift ${\Delta}F$ is used to assess the cracked plate. The possibility of repeatability of the pristine condition signatures is also presented and the appropriate frequency range and interval are uniquely selected through large numbers of experiments.

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Evaluation of an insect-mimicking flapping device actuated by a piezoceramic actuator (곤충 비행원리를 모사한 압전 작동기 구동형 날갯짓 기구의)

  • 박훈철;변도영;구남서;모하메드 샤이푸딘
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.8
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    • pp.55-62
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    • 2006
  • This paper presents experimental evaluation of an insect-mimicking flapping-wing device actuated by a unimorph piezoceramic actuator. Length of each rod and hinge point in the linkage/amplification system are carefully chosen such that the resulting wing motion can mimic clapping of wings in a real insect at the end of upstroke. In addition to this, a pair of corrugated wings are fabricated mimicking zig-zag cross section of a real insect wing. Thanks to the two additional implementation, the improved flapping wing device can generate a larger lift force than the previous model even though area of the new wing is about 50% less than that of the previous wing. In this work, effects of the wing clapping, the wing corrugation, and the input wave form on the lift force generation have been also experimentally investigated. Finally, the vortex generated by the flapping device has been captured by a high speed camera, showing that vortices are produced during up- and down-strokes.

Synergetics based damage detection of frame structures using piezoceramic patches

  • Hong, Xiaobin;Ruan, Jiaobiao;Liu, Guixiong;Wang, Tao;Li, Youyong;Song, Gangbing
    • Smart Structures and Systems
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    • v.17 no.2
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    • pp.167-194
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    • 2016
  • This paper investigates the Synergetics based Damage Detection Method (SDDM) for frame structures by using surface-bonded PZT (Lead Zirconate Titanate) patches. After analyzing the mechanism of pattern recognition from Synergetics, the operating framework with cooperation-competition-update process of SDDM was proposed. First, the dynamic identification equation of structural conditions was established and the adjoint vector (AV) set of original vector (OV) set was obtained by Generalized Inverse Matrix (GIM).Then, the order parameter equation and its evolution process were deduced through the strict mathematics ratiocination. Moreover, in order to complete online structural condition update feature, the iterative update algorithm was presented. Subsequently, the pathway in which SDDM was realized through the modified Synergetic Neural Network (SNN) was introduced and its assessment indices were confirmed. Finally, the experimental platform with a two-story frame structure was set up. The performances of the proposed methodology were tested for damage identifications by loosening various screw nuts group scenarios. The experiments were conducted in different damage degrees, the disturbance environment and the noisy environment, respectively. The results show the feasibility of SDDM using piezoceramic sensors and actuators, and demonstrate a strong ability of anti-disturbance and anti-noise in frame structure applications. This proposed approach can be extended to the similar structures for damage identification.

Vibration Reduction of Composite Helicopter Blades using Active Twist Control Concept (능동 비틀림 제어기법을 이용한 복합재료 로터 블레이드의 진동 억제)

  • Pawar, Prashant M.;You, Young-Hyun;Jung, Sung-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.2
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    • pp.139-146
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    • 2009
  • In this study, an assessment is made for the helicopter vibration reduction of composite rotor blades using an active twist control concept. The piezoceramic shear actuation mechanism along with elastic couplings of composite blades is used for vibration reduction. The rotor blades are modeled as composite box-beams with actuator layers bonded on the outer surfaces of the thin-walled section. The governing equations of motion for helicopter blades are obtained using Hamilton's principle. A time domain unsteady aerodynamic theory with free wake model is used to obtain the airloads. Various rotor configurations with different elastic couplings with appropriate actuator placement are used to investigate the hub vibration characteristics. Numerical results show that a substantial reduction of $N_b$/rev hub vibration can be achieved using the optimal control algorithm.

Active control of delaminated composite shells with piezoelectric sensor/actuator patches

  • Nanda, Namita;Nath, Y.
    • Structural Engineering and Mechanics
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    • v.42 no.2
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    • pp.211-228
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    • 2012
  • Present study deals with the development of finite element based solution methodology to investigate active control of dynamic response of delaminated composite shells with piezoelectric sensors and actuators. The formulation is based on first order shear deformation theory and an eight-noded isoparametric element is used. A coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. A simple negative feedback control algorithm coupling the direct and converse piezoelectric effects is used to actively control the dynamic response of delaminated composite shells in a closed loop employing Newmark's time integration scheme. The validity of the numerical model is demonstrated by comparing the present results with those available in the literature. A number of parametric studies such as the locations of sensor/actuator patches, delamination size and its location, radius of curvature to width ratio, shell types and loading conditions are carried out to understand their effect on the transient response of piezoceramic delaminated composite shells.

Electrical Properties of Piezoceramic PZT with $Nb_2O_5$ Dopant ($Nb_2O_5$를 첨가한 압전 세라믹 PZT의 전기적 특성)

  • Park, J.H.;Choi, H.I.;SaGong, G.
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.336-338
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    • 1991
  • Effects of $Nb_2O_5$ addition ranged from 0.0 to 0.75(wt%) on the microstructure and electrical porperties of PZT ceramics have been investigated. The Pb vacancy concentration increases with increasing NbO content. However, the experimental results show the resistivity increases with increasing $Nb^{5+}$ content. This behavior can be explained as a compensation effect and $Nb^{5+}$ can serve as a donar and contribute electrons to the conduction process. According to the law of mass action, this result may reduce the total charge carrier:thus the resistivity increase with NbO content in PZT.

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