• Title, Summary, Keyword: Piezoelectric fields

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Stress and Displacement Fields of a Propagating Mode III Crack in Orthotropic Piezoelectric Materials (직교이방성 압전재료에서 전파 하는 모드 III 균열의 응력장과 변위장)

  • Lee, Kwang-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.6
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    • pp.701-708
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    • 2010
  • The stress and displacement fields of a permeable propagating crack in orthotropic piezoelectric materials under anti-plane shear mechanical load and in-plane electric load are analyzed. The equations of motion for the propagating crack in piezoelectric materials are developed and the solution on the stress and the displacement fields through an asymptotic analysis was obtained. The influences of the piezoelectric constant and of the dielectric permittivity on the stress and displacement fields at the crack tip are explicitly clarified. Using the stress and displacement fields obtained in this study, the characteristics of stress and displacement at a propagating crack tip in piezoelectric materials are discussed.

Estimation of Piezoelectric Fields built in InxGa1-XGaN Quantum Well Structures using Numerical Analysis (InxGa1-XN/GaN 양자우물 구조의 수치 해석을 이용한 압전장 평가)

  • 김경찬;김태근
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.1
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    • pp.89-93
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    • 2004
  • Piezoelectric fields built in I $n_{x}$G $a_1$$_{-x}$N/GaN (x=0.06∼0.1) quantum wells (QWs) have been estimated by comparing the transition energies, both calculated and measured by photoluminescence (PL). The calculation was numerically carried out with a rectangular QW model, where the effective bandgap considering a bowing facto, energy levels quantized for the lowest lying electrons and heavy holes (1e-lhh), and biaxial compressive strain were included except for the piezoelectric fields. The calculated values were observed to be larger (9∼15 meV) than the measured values by PL, which was considered to be caused by the piezoelectric fields built in InGaN/GaN QW interface. In addition, we observed the energy shift by measuring the EPDPL (excitation power-dependent PL), which was compared with the energy difference caused by the piezoelectric fields.

Mode I Field Intensity Factors of Infinitely Long Strip in Piezoelectric Media

  • Kwon, Soon-Man;Lee, Kang-Yong
    • Journal of Mechanical Science and Technology
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    • v.14 no.8
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    • pp.845-850
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    • 2000
  • We consider the problem of determining the singular stresses and electric fields in a piezoelectric ceramic strip containing a Griffith crack under in-plane normal loading within the framework of linear piezoelectricity. The potential theory method and Fourier transforms are used to reduce the problem to the solution of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. Numerical values on the field intensity factors are obtained, and the influences of the electric fields for PZT-6B piezoelectric ceramic are discussed.

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A comprehensive review on the modeling of smart piezoelectric nanostructures

  • Ebrahimi, Farzad;Hosseini, S.H.S.;Singhal, Abhinav
    • Structural Engineering and Mechanics
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    • v.74 no.5
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    • pp.611-633
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    • 2020
  • In this paper, a comprehensive review of nanostructures that exhibit piezoelectric behavior on all mechanical, buckling, vibrational, thermal and electrical properties is presented. It is firstly explained vast application of materials with their piezoelectric property and also introduction of other properties. Initially, more application of material which have piezoelectric property is introduced. Zinc oxide (ZnO), boron nitride (BN) and gallium nitride (GaN) respectively, are more application of piezoelectric materials. The nonlocal elasticity theory and piezoelectric constitutive relations are demonstrated to evaluate problems and analyses. Three different approaches consisting of atomistic modeling, continuum modeling and nano-scale continuum modeling in the investigation atomistic simulation of piezoelectric nanostructures are explained. Focusing on piezoelectric behavior, investigation of analyses is performed on fields of surface and small scale effects, buckling, vibration and wave propagation. Different investigations are available in literature focusing on the synthesis, applications and mechanical behaviors of piezoelectric nanostructures. In the study of vibration behavior, researches are studied on fields of linear and nonlinear, longitudinal and transverse, free and forced vibrations. This paper is intended to provide an introduction of the development of the piezoelectric nanostructures. The key issue is a very good understanding of mechanical and electrical behaviors and characteristics of piezoelectric structures to employ in electromechanical systems.

Active Control of Sound Fields from Vibrating Plates Using Piezoelectric and Viscoelastic Material (압전재료와 점탄성 재료를 이용한 평판 진동 음장의 능동제어)

  • Kang, Young-Kyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.12
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    • pp.950-955
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    • 2002
  • The coupled finite/boundary element method is used in numerical analysis for acoustic radiation from the vibration of rectangular composite plate which is simply supported. This analysis is validated using the Wallace equation for an isotropic plate. Active control of sound fields has been tarried out using 3 pairs of piezoelectric sensor/actuator and a pair of viscoelastic material by Passive constrained layer damping treatment. The results show that the optimal placement of piezoelectric sensor/actuator and VE patch is required to control the sound fields from a vibrating composite plate.

Finite Element Analysis of the Piezoelectric Behavior of ZnO Nanowires (산화아연 나노와이어의 압전거동에 대한 분석)

  • Lee, Woong
    • Korean Journal of Materials Research
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    • v.28 no.11
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    • pp.671-679
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    • 2018
  • Finite element analyses are carried out to understand the piezoelectric behaviors of ZnO nanowires. Three different types of ZnO nanowires, with aspect ratios of 1:2. 1:31, and 1:57, are analyzed for uniaxial compression, pure bending, and buckling. Under the uniaxial compression with a strain of $1.0{\times}10^{-4}$ as the reference state, it is predicted that all three types of nanowires develop the same magnitude of the piezoelectric fields, which suggests that longer nanowires exhibit higher piezoelectric potential. However, this prediction is not in agreement with the experimental results previously reported in the literature. Such discrepancy is understood when the piezoelectric behaviors under bending and buckling are considered. When only the strain field due to bending is present in bending or buckling, the antisymmetric nature of the through-thickness stain distribution indicates that two piezoelectric fields, the same in magnitude and opposite in sign, develop along the thickness direction, which cancels each other out, resulting in a zero net piezoelectric field. Once additional strain contribution due to axial deformation is superposed on the bending, such field cancelling is compensated for due to the axial component of the piezoelectric field. Such numerical predictions seem to explain the reported experimental results while providing a guideline for the design of nanowire-based piezoelectric devices.

Influence of Applied Electric Fields and Drive Frequencies on The Actuating Displacement of a Plate-type Piezoelectric Composite Actuator (평판형 압전 복합재료 작동기의 작동 변위에 미치는 인가전압 및 구동주파수의 영향)

  • Goo Nam-Seo;Woo Sung-Choong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.5
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    • pp.576-584
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    • 2006
  • The actuating performance test of plate-type piezoelectric composite actuators having different lay-up sequences was experimentally carried out at simply supported and fixed-free boundary conditions. The actuating displacement of manufactured plate-type piezoelectric composite actuator (PCA) was measured using a non-contact laser displacement measurement system. Our results revealed that the actuating displacement with increasing applied electric field at a drive frequency of 1Hz increased non-linearly at the simply supported boundary condition whereas it almost linearly increased at the fixed-free boundary condition. On the other hand, the actuating displacement of piezoelectric composite actuator depended on the applied electric field in a drive frequency range from 1Hz to 10Hz, but its behavior was different in higher drive frequencies beyond 15Hz due to the occurrence of resonance. On the basis of the above experimental results, the bending characteristics of PCAs revealed different behavior depending on applied electric fields, drive frequencies as well as boundary conditions. Therefore, by investigating drive frequencies together with applied electric fields, actuating performance can be easily controlled and PCAs which were fabricated for this study will be sufficiently applied to pumping devices.

Active control of sound fields from vibrating plates using piezoelectric and viscoelastic material (압전재료와 점탄성재료를 이용한 평판진동 음장의 능동제어)

  • 강영규;김재환;최승복
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.311-315
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    • 2002
  • The coupled finite/boundary element method is used in numerical analysis for acoustic radiation from the vibration of rectangular composite plate which is simply supported. This analysis is validated using the Wallace equation for an isotropic plate. Active control of sound fields has been carried out using 3 pairs of piezoelectric sensor/actuator and a pair of viscoelastic material by passive constrained layer damping treatment. The results show that the optimal placement of piezoelectric sensor/actuator and VE patch is required to control the sound fields from a vibrating composite plate.

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Eccentric Crack in a Piezoelectric Strip Under Electro-Mechanical Loading

  • Lee, Kang-Yong;Shin, Jeong-Woo;Kwon, Soon-Man
    • Journal of Mechanical Science and Technology
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    • v.15 no.1
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    • pp.21-25
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    • 2001
  • We consider the problem of determining the singular stresses and electric fields in a piezoelectric ceramic strip containing a Griffith eccentric crack off the center line under anti-plane shear loading with the theory of linear piezoelectricity. Fourier transforms are used to reduce the problem to the solution of two pairs of dual integral equations, which are then expressed to a Fredholm integral equation of the second kind. Numerical values on the stress intensity factor and the energy release rate are obtained, and the influences of the electric fields for piezoelectric ceramics are discussed.

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Nonlocal nonlinear dynamic behavior of composite piezo-magnetic beams using a refined higher-order beam theory

  • Fenjan, Raad M.;Ahmed, Ridha A.;Faleh, Nadhim M.
    • Steel and Composite Structures
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    • v.35 no.4
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    • pp.545-554
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    • 2020
  • The present paper explores nonlinear dynamical properties of piezo-magnetic beams based on a nonlocal refined higher-order beam formulation and piezoelectric phase effect. The piezoelectric phase increment may lead to improved vibrational behaviors for the smart beams subjected to magnetic fields and external harmonic excitation. Nonlinear governing equations of a nonlocal intelligent beam have been achieved based upon the refined beam model and a numerical provided has been introduced to calculate nonlinear vibrational curves. The present study indicates that variation in the volume fraction of piezoelectric ingredient has a substantial impact on vibrational behaviors of intelligent nanobeam under electrical and magnetic fields. Also, it can be seen that nonlinear free/forced vibrational behaviors of intelligent nanobeam have dependency on the magnitudes of induced electrical voltages, magnetic potential, stiffening elastic substrate and shear deformation.