• Title/Summary/Keyword: thickness mode

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Particle displacement distributions of energy-trapped thickness shear vibrations in the piezoelectric substrate (압전체 기판에서 에너지 포획된 두께 전단진동의 변위분포)

  • 이개명
    • Electrical & Electronic Materials
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    • v.9 no.9
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    • pp.954-963
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    • 1996
  • Particle displacement distributions of the fundamental thickness shear vibration mode and overtone modes in an energy-trapped single resonator and an energy-trapped double acoustically coupled filter were calculated. The effects of the width of a pair of partial eletrodes and the magnitude of the plate back of the resonator on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated. And the effects of the width of a pair of partial eletrodes, the width of the gap between two pairs of partial electrodes and the magnitude of the plate back of the filter on the particle displacement distributions of its symmetric vibration mode and anti-symmetric vibration mode were investigated.

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Characteristics Control of a Thickness Mode Piezoelectric Vibrator Using a Negative Impedance Converter Circuit (부임피던스 변환회로를 이용한 두께 모드 압전 진동자의 특성제어)

  • 황성필;김무준;하강열
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.7
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    • pp.600-605
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    • 2002
  • In this paper, a Negative Impedance Converter (NIC) circuit was employed for the electro-mechanical characteristic control of a thickness mode piezoelectric vibrator. Two circular plane piezoelectric vibrators were bonded together and the NIC circuit was connected to one of the vibrators. The theoretical and experimental analysis of the characteristics shown that the quality factor and the electro-acoustic efficiency of the vibrator with the NIC circuit could be improved by 20 times and 2.5 times, respectively.

Voltage Gain Characteristics of Piezoelectric Transformer for Power Supply (Power Supply용 압전 트래스포머의 Voltage Gain특성)

  • 김성진;남성이;이수호;홍재일;류주현
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.06a
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    • pp.191-194
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    • 1998
  • This Paper present a new structure for a piezoelectric transformer, operating in thickness extensional vibration mode. Modified PbTiO$_3$ family ceramics were used for the Piezoelectric transformer, because it is a material with large anisotropy between electromechanical coupling facters k$\sub$t/ and k$\sub$p/. Piezoelectric transformer was fabricated that is 20mm long, 20mm wide and 3.1mm thick. Resonant frequencies of sencond thickness extensional vibration mode is 1.72MHz at loading resistance 100{$\Omega$]. And Voltage gain of piezoelectric ceramics is showed 0.53 at resonant frequency of sencond thickness extensional vibration mode.

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Analysis and Design of Si3N4 Rib-optical Waveguides for Evanescent-wave Integrated-optical Biosensors (소산파 집적광학 바이오센서에 적합한 Si3N4 립-광도파로 해석 및 설계에 관한 연구)

  • Jung, Hongsik
    • Korean Journal of Optics and Photonics
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    • v.30 no.1
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    • pp.15-22
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    • 2019
  • $Si_3N_4$ rib-optical waveguides for evanescent-wave integrated-optical biosensors were analytically interpreted, to derive the single-mode propagation conditions. The integrated-optical biosensor structure based on two-mode interference was proposed, and the rib width and thickness and core thickness for a single-mode and two-mode waveguide (sensing region) were proposed to be $3{\mu}m$, 2 nm, and 150 nm and $3{\mu}m$, 20 nm, and 340 nm respectively. The optical characteristics of each guided-wave mode were investigated utilizing the film mode-matching (FMM) analysis.

Electrical and Piezoelectric Properties of PbLa(Mn,SbTi)$O_3$ceramics as a function of $MnO_2$$_2$addition ($MnO_2$첨가에 따른 PbLa(Mn,SbTi)$O_3$세라믹스의 유전 및 압전특성)

  • 오동언;민석규;윤광희;류주현;박창엽
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.684-688
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    • 2001
  • The structural, piezoelectric and dynamic range characteristics of modified PbTi $O_3$ceramics were investigated as a function of Mn $O_2$addition. With the increase of Mn $O_2$addition, Curie temperature was decreased. As the increase of Mn $O_2$addition, mechanical quality factor ( $Q_{mt3}$) in the third over tone thickness mode was increased. Dynamic range in the third over tone thickness mode was also increased with the increase of Mn $O_2$addition. The composition ceramics added to 0.075wt% Mn $O_2$showed the best properties for SMD type resonator using third over tone thickness vibration in terms of high Curie temperature more than 31$0^{\circ}C$ and dynamic range of 49.38dB.B.

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Static Compressive Strength of Thick Unidirectional Carbon Fiber - Epoxy Laminate (두꺼운 일방향 탄소섬유-에폭시 적층판의 정적 압축 강도 연구)

  • Lee, J.;Soutis, C.;Gong, Chang-Deok
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.61-65
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    • 2005
  • Existing test methods for thick-section specimens ( 4mm) have not provided precise compressive properties to date for the analysis and design of thick structure. A survey of the failure behaviour of such thick specimens revealed that the failure initiated at the top corner of the specimen and propagated down and across the width of the specimen as premature failure, not typically reported for thin compression specimens. In the current study, the premature failure was successfully avoided during compressive testing and the failure mode was quite similar regardless of increasing specimen thickness and specimen volume. Failure mode was similar regardless of increasing specimen thickness and specimen volume, i.e. brooming failure mode combined with longitudinal splitting, interlaminar cracking, fibre breakage and kinkband formation (fibre microbuckling). Nevertheless, average failure strengths of the specimens decreased with increasing specimen thicnkiness from 2mm to 8mm with the T800/924C system (36% strength reduction) and specimen volumes from scaling factor I to scaling factor 4 with the IM7/8552 system (46% strength reduction). It was revealed from the literature$^{11}$ that the thickness effect and scaling effect arc caused by manufacturing defects such as void content and fibre waviness.

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Guided wave analysis of air-coupled impact-echo in concrete slab

  • Choi, Hajin;Azari, Hoda
    • Computers and Concrete
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    • v.20 no.3
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    • pp.257-262
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    • 2017
  • This study aims to develop a signal processing scheme to accurately predict the thickness of concrete slab using air-coupled impact-echo. Air-coupled impact-echo has been applied to concrete non-destructive tests (NDT); however, it is often difficult to obtain thickness mode frequency due to noise components. Furthermore, apparent velocity in concrete is a usually unknown parameter in the field and the thickness of the concrete slab often cannot be accurately measured. This study proposes a signal processing scheme using guided wave analysis, wherein dispersion curves are drawn in both frequency-wave number (f-k) and phase velocity-frequency ($V_{cp}-f$) domains. The theoretical and experimental results demonstrate that thickness mode frequency and apparent velocity in concrete are clearly obtained from the f-k and $V_{cp}-f$ domains, respectively. The proposed method has great potential with regard to the application of air-coupled impact-echo in the field.

Piezoelectric Properties on the Thickness of Specimens with PZT/Epoxy Composite Materials of 1-3 Connectivity (PZT/Epoxy (1-3형) 복합재료의 두께변화에 따른 압전특성)

  • 김용혁;김호기;김진수;이덕출
    • Journal of the Korean Ceramic Society
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    • v.25 no.1
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    • pp.7-14
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    • 1988
  • In this paper, piezoelectric composite materials of 1-3 connectivity were prepared by using "dicing-filling" technique with PZT ceramics and epoxy polymers, and the dependence of piezoelectric properties on the thickness of specimens was investigated. In case that the PZT volume percent is 18.1%, according to an increment of thickness, the dielectric constant of composites( 33) is unchangeable, which is about 200, the piezoelectric coefficient (d33) is somewhat increased, which is about 240-280 (PC/N) and the electromechanical coupling factor of thickness mode(kt) is proportioned, but radial mode(kp) is constant.

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Finite Element Simulation of Thickness Vibration Mode Multilayer Piezoelectric Transformer (두께 진동모드 적층형 압전 변압기의 유한요소 시뮬레이션)

  • Yoo, Kyung-Jin;Lee, Sang-Ho;Yoo, Ju-Hyun;Hong, Jae-Il;Son, Eun-Young
    • Proceedings of the KIEE Conference
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    • 2006.07b
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    • pp.1059-1060
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    • 2006
  • In this study, vibration mode multilayer piezoelectric transformer was designed and thickness simulated using ANSYS of finite element method simulator for investigating its optimum conditions ist. As a results, resonant frequency was decreased with the increase of output layer thickness, Output voltage, maximum displacement and maximum stress at 0.34mm thickness transformer were 228.1 V, $0.42{\mu}m,\;8.78[N/m^2]$ respectively.

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Finite Element Analysis of Step-down Piezoelectric Transformer with Various Shape (형태의 변화에 따른 강압용 압전변압기의 유한요소해석)

  • Chong, Hyon-Ho;Park, Tae-Gone;Kwon, Oh-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.697-700
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    • 2003
  • This paper presents design and analysis of step-down piezoelectric transformer for application to AC-adapters. These transformers are consist of rectangular type and disk type multilayered piezoelectric ceramic plate. This piezoelectric transformer operated in third thickness resonance vibration mode. Finite element methode(FEM) was used for analysing transformer. Vibration mode and electric field of piezoelectric transformer were simulated at resonance frequency. As results, rectangular type transformer's output voltage was higher than the disk type. But disk type transformer's current was lagger than rectangular type. These results are assumed that disk type transformer's mixed vibration mode influence transformer's output characteristics. From these results, we expect that disk type piezoelectric transformer is more adoptable than rectangular plate type piezoelectric transformer for AC adapters.

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