• Title/Summary/Keyword: mode coupling

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Free Vibration Analysis of a Rotating Cantilever Beam Made-up of Functionally Graded Materials (경사기능재료를 사용한 회전하는 외팔보의 진동해석)

  • Lee, Ki Bok;Yoo, Hong Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.8
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    • pp.742-751
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    • 2013
  • The vibration analysis of a rotating cantilever beam made-up of functionally graded materials is presented based on Timoshenko beam theory. The material properties of the beams are assumed to be varied through the thickness direction following a simple power-law form. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of power-law exponent, angular speed, length to height ratio and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.

Influence of Internal Resonance on Responses of an Autoparametric Vibration Absorber under Random Excitation (불규칙 가진력을 받는 동흡진기의 내부공진효과)

  • 조덕상;이원경
    • Journal of KSNVE
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    • v.10 no.6
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    • pp.1041-1047
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    • 2000
  • The main objectives of this study are to examine the random response of a vibration absorber system with autoparametric coupling in the neighborhood of internal resonance by Gaussian closure and to compare the results with those obtained by Monte Carlo simulation. The numerical simulation is found to support the main features of the nonlinear modal interaction in the neighborhood of internal resonance conditions. While the Gaussian closure exhibits regions of multiple solutions in the neighborhood of internal resonance, the numerical simulation gives only one solution depending on the assigned initial conditions. The on-off intermittency phenomena of the cantilever mode is observed in the Monte Carlo simulation over a small range of parameter.

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Vibration Analysis of Rotating Inward Cantilever Beams With a Tip-Mass (집중질량을 갖는 회전중심방향 자유단 외팔보의 진동해석)

  • Lee, Gun Ho;Yoo, Hong Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.389-391
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    • 2014
  • The Vibration Analysis of Rotating Inward Beams Considering The Tip-Mass is presented based on Euler-Bernoulli beam theory. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of angular speed, and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.

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Rotordynamic design of a turbogenerator supported by air foil bearings (공기포일베어링에 지지된 터보제너레이터의 회전체동역학적 설계)

  • Kim, Y.C.;An, K.Y.;Park, M.R.;Park, J.Y.;Choi, B.S.;Lee, A.S.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.271-276
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    • 2006
  • This paper shows the rotordynamic characteristics of a turbo-generator for a BOP of a fuel cell system. The rotor-bearing system consists of magnetic shaft and compressor-turbine shaft, and the two shafts are connected by spline coupling and supported by oil free air foil bearing. Preliminary design according to several parameter is considered in detail. Static and dynamic characteristics of the AFB are estimated by the soft elasto-hydrodynamic analysis technique and the perturbation method. The results of the natural frequencies, mode shape, and unbalance response analysis are presented.

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Recent Advances in Filter Topologies and Realizations for Satellite Communications

  • Fahmi, Mohamed M.;Ruiz-Cruz, Jorge A.;Mansour, Rafaat R.;Zaki, Kawthar A.
    • Journal of Communications and Networks
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    • v.13 no.6
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    • pp.625-632
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    • 2011
  • This paper presents an overview of recent advances in radio frequency and microwave filter topologies for satellite communication systems. Many types of filters have been developed during the last years in order to satisfy the demands of modern applications in both terrestrial systems and onboard spacecrafts, leading to a great variety of aspects such as transfer functions, resonator implementations or coupling structures. This paper revisits some of the last advances in this area, including the modeling and full-wave simulation. Some recent designs using dual-mode cavities along with other novel implementations in ridge waveguide will be shown.

Lumped Element MMIC Direction Coupler Based on Parallel Coupled-Line Theory (평행 결합선로 이론에 근거한 MMIC 집중 소자형 방향성 결합기)

  • Kang Myung-Soo;Park Jun-Seok;Lee Jae-Hak;Kim Hyeong-Seok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.53 no.11
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    • pp.577-582
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    • 2004
  • In this paper, lumped equivalent circuits for a conventional parallel directional coupler are proposed. This equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of parallel-coupled line. By using the derived design formula, we have designed the 3dB and 4.7dB MMIC couplers at the center frequency of 3.4GHz and 5.6GHz respectively. Measurements for the designed MMIC directional couplers show at 4dB and 5.2dB-coupling value at the center frequency of 3.4GHz and 5.6GHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper

AlN-Si Thin Film Bulk Acoustic Over-moded Resonator (AlN 압전 박막과 Si을 이용한 체적탄성파 Over-moded 공진기)

  • 이시형;이전국;김상희;김종헌;윤기현
    • Journal of the Korean Ceramic Society
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    • v.37 no.12
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    • pp.1198-1203
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    • 2000
  • AlN와 Si을 이용하여 체적 탄성파 over-moded 공진기를 형성하였다. 높은 c-축 배향성을 갖는 AlN 압전박막은 sputtering에 의해 저온에서 증착하였다. AlN 박막의 c-축 배향성은 기판과 타겥의 거리가 가까울수록, 증착 압력이 낮을수록 (002) 면으로의 성장이 촉진되었다. Si 기판을 이용한 over-moded 공진기로부터 TFR의 임피던스를 산출한 결과 공진영역의 면적에 가장 의존하였다. Al/AlN/Al로 이루어진 TFR의 입력 임피던스는 공진 영역이 크기가 200㎛×200㎛인 경우 가장 50Ω에 근접하였다. Over-moded 공진 특성은 Si 기판의 낮은 Q로 인해 mode 수 294인 2.60976 GHz에서 0.109%의 유효 전기기계결합계수(K/sub eff/²)와 0.3의 K/sub eff/²·Q값을 보였다.

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Characteristics of THz Pulse Propagation on Teflon Covered Two-Wire Lines

  • Jo, Jeong Sang;Jeon, Tae-In
    • Journal of the Optical Society of Korea
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    • v.19 no.6
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    • pp.560-565
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    • 2015
  • We report efficient direct coupling of THz dipole antenna pulses onto air spaced two-wire transmission lines and Teflon covered two-wire lines. The air spaced two-wire lines show TEM mode propagation with very small group velocity dispersion (GVD) and relatively low attenuation. The Teflon covered two-wire lines showed comparatively much higher attenuation and GVD. However, the Teflon covered two-wire lines show a very good guiding property when the lines are curved. Although the lines are circled only 5.0 cm in diameter, there is no additional attenuation compared to straight the lines.

Development of low-loss surface plasmon waveguides by using polymeric cladings (폴리머 크래딩을 이용한 저손실 표면플라즈몬 광도파로 개발)

  • Ju, Jeong-Jin;Park, Seon-Taek;Kim, Min-Su;Park, Seung-Gu;Kim, Jin-Tae;Choe, Jung-Seon;Gwon, Yong-Hwan;Lee, Myeong-Hyeon
    • Proceedings of the Optical Society of Korea Conference
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    • 2008.02a
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    • pp.125-126
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    • 2008
  • We investigate characteristics of gold and silver metal strip waveguides based on long range surface plasmon polaritons (LRSPPs) along thin metal strips embedded in a polymer for practical applications at the wavelengths of 1.31 and 1.55 um. Guiding properties of the metal strip waveguides are theoretically and experimentally evaluated. In addition, surrounding technologies such as the development of TM-mode laser, coupling properties, as well as high-speed digital signal transporting experiments will be explained for board-to-board optical interconnections by using the LRSPP waveguides.

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The Application of MultiLayered Primitive-Composite Model for Integrated Design System of Agricultural Facilities (농업시설물의 통합설계시스템 개발을 위한 객체 모델링에 관한 연구(구조 및 재료 \circled1))

  • 배연정;이정재;윤성수;김한중
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2000.10a
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    • pp.226-232
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    • 2000
  • The design of agricultural facilities is the consistent activities, which systematically analyze all the actual conditions, design the unit structures, and improve the faming environment through efficient organization of the unit facility. The design of agricultural facilities is composed of site study, preliminary design, primary design, and detail design. Integrated design system can manage and process the information created by and used in all steps of design process. Formal data models of these design activities are important conceptual steps in development of integrated design system. However, most of existing models are not available for agricultural facilities. To support efficiently developing the integrated design system of agricultural facilities, we have developed the Multi-Layered Primitive-Composite mode I through object-oriented analysis of agricultural facilities. The MPC model not only satisfies the characteristics of agricultural facility, such as variety, coupling, informal data, but also improves abilities of integrated design system such as extensibility, flexibility, and granularity. The paper presents a formal definition of the MPC model.

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