• Title/Summary/Keyword: 압전-구조 연성해석

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Model Order Reduction for Piezoelectric-Structural Systems with Coriolis Effect (코리올리 효과를 가진 압전-구조계의 모델차수축소법)

  • Han, Jeong-Sam
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.713-716
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    • 2010
  • 본 논문에서는 코리올리 효과를 가진 압전-구조 시스템의 주파수응답 해석을 효율적으로 수행하기 위한 크리로프 부공간 모델차수축소법을 제안하였다. 이 방법은 초기 유한요소모델과 축소모델의 전달함수의 계수인 모멘트를 일치시키는 방법을 이용하는 축소기법으로 이미 대형 유한요소모델의 주파수응답 해석에 효과적으로 이용되고 있다. 예제로 고려된 압전형 미소 각속도계의 해석에는 압전구동 하중과 구조체의 회전에 따른 원심력이 동시에 입력하중으로 고려되는 다중입력의 경우이므로 변환행렬 V의 생성시, block Arnoldi 과정을 이용하여 두 하중의 효과를 축소모델에 함께 고려한다. 본 문제에 제안된 축소기법을 이용한 결과, 축소모델을 이용하여 원래 시스템의 관심영역의 주파수응답을 작은 차수의 모델로도 정확하게 계산할 수 있음을 확인하였다. 본 논문에서 제안된 방법을 이용하면 다양한 가진조건과 각속도 입력 하에서의 주파수응답을 정확하고 더욱 효율적으로 계산할 수 있을 것이다.

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Acoustic Characteristics Analysis of piezoelectric Underwater Acoustic Sensors Using Finite Element Method. (유한요소법을 이용한 압전 수중음향센서의 음향특성 해석)

  • Son Sun Bong;Kim Jae Hwan
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.253-256
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    • 2000
  • 본 연구에서는 유한요소법(FEM)을 이용하여 압전 수중음향센서의 모델링 및 음향특성을 해석하였다. 압전 복합구조 수중음향센서의 해석에서 기본적인 압전-탄성 구조물과 유체-구조물의 연성해석을 위한 유한요소 정식화를 하였으며 무한영역의 음향유체를 처리하기 위하여 IWEE(Infinite Wave Envelop Element)를 도입하였다. Topilz형 수중음향센서를 수중 산란체로 볼 경우 입사파가 산란체의 표면을 가진할 때 산란체로부터 발생되는 산란파는 IWEE로 인하여 무한 유체영역에서의 산란파의 감소특성을 갖게되어 무한영역을 유한영역으로 나눈 인위적인 경계에서 반사가 일어나지 않게 되므로 산란파의 음압을 정확히 구할 수 있었다. 또한, 이러한 산란해석을 바탕으로 입사파에 대한 음향센서 내부의 전기적 응답특성인 RVS(Receiving Voltage Signal)를 구하였다. 이러한 일련의 연구 과정들은 소나(SONAR) 시스템을 정확히 해석하고 음향특성을 예측하는 데 큰 도움이 될 것이다.

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Finite Element Analysis for Acoustic Characteristics of Piezoelectric Underwater Acoustic Sensors (압전 수중음향센서 음향특성의 유한요소해석)

  • 김재환;손선봉;조철희;조치영
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.1
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    • pp.68-76
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    • 2001
  • Sonar is the system that detects objects and finds their location in water by using the echo ranging technique. In order to have excellent performance in variable environment, acoustic characteristics of this system must be analyzed accurately. In this paper, based on the finite element analysis, modeling and analysis of acoustic characteristics of underwater acoustic sensors are preformed. Couplings between piezoelectric and elastic materials, and fluid and structure systems associated with the modeling of piezoelectric underwater acoustic sensors are formulated. In the finite element modeling of unbounded acoustic fluid, IWEE (Infinite Eave Envelop Element) is adopted to take into account the infinite domain. When an incidence wave excites the surface of Tonpilz underwater acoustic sensor, the scattered wave on the sensor is founded by satisfying the radiation condition at the artificial boundary approximately. Based on this scattering analysis, the electrical response of the underwater acoustic sensor under incidence, so called RVS (Receiving Voltage Signal) is founded accurately. This will devote to design Sonar systems accurately.

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Effect of Check Valve Characteristics on Flow Rate of the Small Piezoelectric-Hydraulic Pump (체크밸브 특성이 소형 압전유압펌프 유량에 미치는 효과)

  • Nguyen, Anh Phuc;Hwang, Jai-Hyuk;Hwang, Yong-Ha;Bae, Jae-Sung
    • Journal of Aerospace System Engineering
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    • v.12 no.5
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    • pp.54-68
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    • 2018
  • The objective of this study is to analyze the effect of dynamic characteristics of the check valve applied to the small piezoelectric-hydraulic pumps on flow rate formation. The flow rate of the piezoelectric-hydraulic pump is a key factor in the formation of the load pressure to operate the brake system. At this time, the natural frequency of the check valve operating in the fluid has a great influence on the formulation of the flow rate of the piezoelectric-hydraulic pump. In addition, the natural frequency of the check valve is affected by the gap between the check valve and the pump seat. In this study, the natural frequency of the check valve according to the gap between the check valve and the pump seat was calculated through the fluid-structure interaction analysis. The flow rate obtained from the simulation result was verified by comparing it with the result from the flow rate experiment using the developed piezoelectric-hydraulic pump.

Three Dimensional Electro-Fluid-Structural Interaction Simulation for Pumping Performance Evaluation of a Valveless Micropump (무밸브 마이크로 펌프의 성능평가를 위한 3차원 전기-유체-구조 상호작용 해석)

  • Pham, My;Phan, Van Phuoc;Han, Cheol-Heui;Goo, Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.8
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    • pp.744-750
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    • 2009
  • In this study, the pumping performance of a piezoelectric valveless micropump is simulated. The micropump, which was developed in the previous work, is composed of a four-layer lightweight piezocomposite actuator, a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, the fluid domain and the structural domain are coupled in the three-dimensional simulation. We used ANSYS for the piezoelectric and structural domains and ANSYS CFX for the fluid domain. The effects of driven frequency on the flow rate have been investigated by simulating the flow characteristics for 10 Hz and 40 Hz driven frequencies. The flow rates with respect to driven frequencies up to 300 Hz have been calculated.

Reduction of Free Edge Peeling Stress in Composite Laminates under Bending Load (굽힘하중이 가해지는 복합재 평판 자유단에서의 박리응력 감소 연구)

  • Jung, Seok-Joo;Sung, Myung-Kyun;Kim, Heung Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.497-502
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    • 2015
  • In this paper, a stress function-based approach was proposed to analyze the reduction of free-edge peeling stress in smart composite laminates using piezoelectric actuator under bending load. Electro-mechanically coupled governing equation was obtained by complimentary virtual work principle. The stress state was solved by the generalized eigenvalue procedure. The free-edge peeling stress of smart composite laminates was reduced by the piezoelectric actuation. The reduction rate of peeling stress in cross-ply composite laminate is larger than that in angle ply composite laminate.

Analysis of coupled electro-mechanical system by using a nine-node assumed strain shell element (9 절점 가정변형률 쉘 요소를 이용한 전기-기계연성 시스템 해석)

  • Lee, Sang Gi;Park, Hun Cheol;Yun, Gwang Jun;Jo, Chang Min
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.2
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    • pp.25-34
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    • 2003
  • In the present paper, formulation of a nine-node assumed strain shell element is modified and extended for analysis of actuator embedded/attached structures. The shell element can alleviate locking and has sic DOFs per node by discarding assumption of no thickness change. In modeling of the physicalquantities, we have assumed linear strain field through the whole thickness direction. The electric and mechanical quantities have been coupled through the constitutive equations. Unlike typical shell element, the present shell element allows thickness change. Thus, three-dimensional piezoelasticity can be accurately simulated. Base on the formulation, a finite element program is generated and the code is validated by solving numerical examples. The results from the present work are well agreed with those from other references.

Thermoelectromechanical analysis of piezoelectric fiber composites (열-전기-기계 하중하의 압전섬유 복합재료 해석)

  • Kim, Jun-Sik
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2011.04a
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    • pp.290-291
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    • 2011
  • 본 논문에서는 열-전기-기계 하중 하의 지능형 복합재료 보 모델을 전산점근해석기법에 기초하여 개발하였다. 열-전기-기계 하중 하의 구조물은 지난 십년간 많은 연구가 있어왔으나, 주로 고전적 보 모델에 기반을 두어 진행되어져 왔다. 멀티피직스 환경하의 구조물은 여러 가지 하중의 조합과 이에 따른 연성효과의 고려가 필수적이다. 따라서 공학적인 가정이 없는 점근해석기법은 보다 정확한 등가 보 모델을 개발하는데 있어 기반요소가 될 수 있다. 본 연구에서는 3차원 멀티피직스 구성방정식으로부터 출발하여 점근기법을 적용 체계적으로 등가 보 모델을 유도하고 그 해석 결과를 고찰하고자 한다.

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Vibration Control of Composite Wing-Rotor System of Tiltrotor Aircraft (틸트로터 항공기 복합재료 날개의 진동 제어)

  • Song, Oh-Seop
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.6
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    • pp.509-516
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    • 2007
  • Mathematical modeling and vibration control of a tiltrotor aircraft composite wing-rotor system are investigated in this study. A wing-mounted rotor can be tilted from the vertical position to a horizontal one, and vice versa. Effect of vibration control of the wing-rotor system via piezoelectricity is studied as a function of tilt angle, ply angle of composite wing and rotor's spin speed. Composite wing is modeled as a thin-walled box beam having a circumferentially uniform stiffness configuration that produces elastic coupling between flap-lag and between extension-twist behavior. Numerical simulations are provided and pertinent conclusions are outlined.

Finite Element Modeling for the Analysis of In- and Out-of-plane Bulk Elastic Wave Propagation in Piezoelectric Band Gap Structures (압전 밴드 갭 구조물의 면내·외 방향 체적 탄성파 전파 특성 해석을 위한 유한요소 모델링)

  • Kim, Jae-Eun;Kim, Yoon-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.8
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    • pp.957-964
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    • 2011
  • This investigation presents a finite element method to obtain the transmission properties of bulk elastic waves in piezoelectric band gap structures(phonon crystals) for varying frequencies and modes. To this end, periodic boundary conditions are imposed on a three-dimensional model while both in-plane and out-of-plane modes are included. In particular, the mode decoupling characteristics between in-plane and out-of-plane modes are identified for each electric poling direction and the results are incorporated in the finite element modeling. Through numerical simulations, the proposed modeling method was found to be a useful, effective one for analyzing the wave characteristics of various types of piezoelectric phononic band gap structures.