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Vibration Analysis of Special Orthotropic Laminated Composite Plates under Axial Loadings (축방향 하중을 받는 특별직교이방성 적층복합판의 진동해석)

  • Won, Chi Moon
    • Journal of Korean Society of Steel Construction
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    • v.18 no.1
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    • pp.93-100
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    • 2006

  • A simple but precise method of calculating the natural vibration frequencies of composite laminated plates with all-simple support and under axial loadings is presented herein. This method uses deflection influence surfaces, which can be obtained by any method for vibration analysis and member due to the inertia force under resonance condition. Beginning with an initially guessed mode shape, the exact mode shape is obtained by the process similar to iteration. In this paper, equations are given for the case of special orthotropic laminates. The same equations, however, can be used for any laminate as long as ${B_1_6}$, ${B_2_6}$, ${D_1_6}$, and ${D_2_6}$ are negligible as the number of plies increases. Some laminates that possess such properties are presented in the paper.

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Improved design of a directional coupler by a novel concept (방향성 결합기의 성능 및 허용오차 개선을 위한 신제안)

  • 최철현;박순룡;오범환
    • Korean Journal of Optics and Photonics
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    • v.11 no.6
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    • pp.405-410
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    • 2000

  • We propose a novel design concept to improve extinction ratio by minimizing $Cv_e-Cv_o$ . Improvements of loss and fabrication error limit are also obtained by this hybrid design of the lateral shift and curved waveguide to control transfer coefficients, $Cv_e and Cv_o$ . The concept of lateral shift merges two transfer coefficients, and additional curved waveguide controls mode profile asymmetrically to help this minimizing effect of $Cv_e-Cv_o$ with no serious decrease in transfer efficiency. For a given InP based waveguide structure, the mode propagation analysis with an effective index approximation provided a calculational improvement of extinction ratio to -39 dB and fabrication error limit to $57.19\mu\textrm{m}$, with a structure design of $300\mu\textrm{m}$ waveguide curvature and $0.1\mu\textrm{m}$lateral shift. shift.

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