• Title/Summary/Keyword: out-of-plane constraint

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Out-of-plane Structural Intensity Analysis of Rectangular Thick Plate (직사각형 후판의 면외 진동인텐시티 해석)

  • Kim, Kook-Hyun;Cho, Dae-Seung
    • Journal of Ocean Engineering and Technology
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    • v.26 no.4
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    • pp.42-49
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    • 2012
  • A numerical method is presented for an out-of-plane structural intensity analysis of rectangular thick plates with arbitrary elastic edge constraints. The method adapts an assumed mode method based on Timoshenko beam functions to obtain the velocities and internal forces needed for a structural intensity analysis. To verify the presented method, the structural intensity of a square thick plate under harmonic force excitation, for which four edges are simply supported, is analyzed, and the result is compared with existing solutions using the assumed mode method based on trigonometric functions. In addition, numerical analyses are carried out for a rectangular-shaped thick plate under harmonic force excitations, of which three edges are simply supported and one edge utilizes an arbitrary elastic edge constraint. These numerical examples show the good accuracy and applicability of the presented method for rectangular thick plates with arbitrary edge constraints.

The design of XYZ 3-axis stage for AFM system (AFM 시스템을 위한 XYZ 3축 스테이지의 설계)

  • 김동민;김기현;심종엽;권대갑;엄천일
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.36-36
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    • 2002
  • To Establish of standard technique of length measurent in 2D plane, we develope AFM system. The XY scanner scans the sample only in XY plane, while the Z scanner scans the specimen only in Z-direction. Cantilever tip is controlled to has constant height relative to speciman surface by feedback of PSPD signal. To acquire high accuracy, Z-axis measuring sensor will be added.(COXI or others). In this paper we design XYZ stage suitable for this AEM system. For XY stage, single module parallel-kinnematic flexure stage is used which has high orthogonality and minimum out-of-plane motion. To obtain best performance optimal design is performed. For XY stage, to be robust about parasitic motion optimal design of maximizing Z and tilt stiffness is performed under the constraint of motion range and stage size. And for Z stage, optimal design of maximizing 1st resonant frequency is performed. Because if resonant frequency is get higher, scan speed is improved. So it makes reduce the error by sensor drift. Resultly XYZ stage each have 1st natural frequency of 115㎐, 201㎐, 2.66㎑ and range 109㎛, 110㎛, 12㎛.

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Cancellation of MRI Motion Artifact in Image Plane

  • Kim Eung-Kyeu
    • Journal of the Institute of Convergence Signal Processing
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    • v.1 no.1
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    • pp.49-57
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    • 2000
  • In this study, a new algorithm for canceling a MRI artifact due to the translational motion In the image plane is described. Unlike the conventional iterative phase retrieval algorithm, in which there is no guarantee for the convergence, a direct method for estimating the motion is presented. In previous approaches, the motions in the x(read out) direction and the y(phase encoding) direction were estimated simultaneously. However, the feature of x and y directional motions are different from each other. By analyzing their features, each x and y directional motion is canceled by the different algorithms in two steps. First, it is noticed that the x directional motion corresponds to a shift of the x directional spectrum of the MRI signal, and the non-zero area of the spectrum just corresponds to the projected area of the density function on the x axis. So the motion is estimated by tracing the edges between non-zero area and zero area of the spectrum, and the x directional motion is canceled by shifting the spectrum in an reverse direction. Next, the y directional motion is canceled by using a new constraint condition, with which the motion component and the true image component can be separated. This algorithm is shown to be effective by using a phantom image with simulated motion.

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Constrained Integer Multiobjective Linear Fractional Programming Problem

  • Thirwani, Deepa;Arora, S.R.
    • Journal of the Korean Operations Research and Management Science Society
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    • v.21 no.3
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    • pp.227-236
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    • 1996
  • In this paper an algorithm based on cutting plane approach is developed which constructs all the efficient p-tuples of multiobjective integer linear fractional programming problem. The integer solution is constrained to satisfy and h out of n additional constraint sets. A numerical illustration in support of the proposed algorithm is developed.

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Deformation Analysis of Injection Molded Articles due to In-mold Residual Stress and Subsequent Cooling after Ejection (사출 성형품의 금형내 잔류음력과 이형후 냉각에 의한 후변형 해석)

  • Yang, Sang-Sik;Gwon, Tae-Heon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.2
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    • pp.340-348
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    • 2002
  • Deformation analysis of injection molded articles whose geometry is considered as the assembly of thin flat plates has been conducted. For the in-mold analysis, thermo-viscoelastic stress calculation of thermo-rheologically simple amorphous polymer and in-mold deformation calculation considering the in-plane mold constraint have been done. Free volume theory has been used to represent the non-equilibrium density state during the fast cooling. At ejection, instantaneous deformation takes place due to the redistribution of in-mold residual stress. During out-of-mold cooling after ejection, thermoelastic model based on the effective temperature has been adopted for the calculation of out-of-mold deformation. In this study, emphasis is also made on the treatment with regard to lateral constraint types during molding process. Two typical mold geometries are used to test the numerical simulation modeling developed in this study.

Wafer-Level Packaged MEMS Resonators with a Highly Vacuum-Sensitive Quality Factor

  • Kang, Seok Jin;Moon, Young Soon;Son, Won Ho;Choi, Sie Young
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.5
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    • pp.632-639
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    • 2014
  • Mechanical stress and the vacuum level are the two main factors dominating the quality factor of a resonator operated in the vacuum range 1 mTorr to 10 Torr. This means that if the quality factor of a resonator is very insensitive to the mechanical stress in the vacuum range, it is sensitive to mainly the ambient vacuum level. In this paper, a wafer-level packaged MEMS resonator with a highly vacuum-sensitive quality factor is presented. The proposed device is characterized by a package with out-of-plane symmetry and a suspending structure with only a single anchor. Out-of-plane symmetry helps prevent deformation of the packaged device due to thermal mismatch, and a single-clamped structure facilitates constraint-free displacement. As a result, the proposed device is very insensitive to mechanical stress and is sensitive to mainly the ambient vacuum level. The average quality factors of the devices packaged under pressures of 50, 100, and 200 mTorr were 4987, 3415, and 2127, respectively. The results demonstrated the high controllability of the quality factor by vacuum adjustment. The mechanical robustness of the quality factor was confirmed by comparing the quality factors before and after high-temperature storage. Furthermore, through more than 50 days of monitoring, the stability of the quality factor was also certified.

A New Anisoparametric Out-of-Plane Deformable Curved Beam Element (새로운 부등매개변수 면회변형 곡선보 요소)

  • Yu, Jae-Hyeong;Yu, Seung-Won;Min, Ok-Gi
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.4
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    • pp.582-591
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    • 2001
  • It is known that the reduced integration, modified shape function, anisoparametric and non-conforming element can reduce the error induced by stiffness locking phenomenon in the finite element analysis. In this study, we propose new anisoparametric curved beam element. The new element based on reduced minimization theory is composed of different shape functions in each displacement field. By the substitution of this modified shape function, the unmatched coefficient that cause stiffness locking in the constraint energy is eliminated. To confirm the availability of this new model, we performed numerical tests for a simple model. As a result of numerical test, the undulate stress patterns are disappeared in static analysis, and displacements and stresses are close to exact solution. Not only in the static analysis but also in the eigen analysis of free vibrated curved beam model, this element shows successful convergent results.

Magnetic Properties of Multiferroic $BiFeO_3/BaTiO_3$ Bi-layer Thin Films

  • Yang, P.;Byun, S.H.;Kim, K.M.;Lee, Y.H.;Lee, J.Y.;Zhu, J.S.;Lee, H.Y.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.06a
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    • pp.318-319
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    • 2008
  • In this article, magnetic properties of multiferroic bi-layer $BiFeO_3$ (BFO)/$BaTiO_3$ (BTO) thin films were studied. It was found that the magnetization increased by the insertion of BTO buffer layer even though the interfacial stress was slightly relaxed, which indicated a coupling between the ferroelectric and ferromagnetic orders. Furthermore, with slightly increase of BFO film thickness, both BFO and BFO/BTO bi-layer films showed anisotropic magnetic properties with higher in-plane magnetization than the values measured out-of-plane. These are attributable to strain constraint effect at the interface.

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Deformation Analysis of Injection Molded Articles due to In-mold Residual Stress and Cooling after Ejection (사출 성형품의 금형내 잔류응력과 이형후 냉각에 의한 후변형 해석)

  • Yang, Sang-Sik;Kwon, Tai-Hun
    • Proceedings of the KSME Conference
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    • 2001.06c
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    • pp.251-256
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    • 2001
  • Deformation analysis of injection molded articles whose geometry is considered as the assembly of the thin flat plates has been conducted. For the in-mold analysis, thermo-viscoelastic stress calculation of rheologically simple amorphous polymer and in-mold deformation calculation considering the in-plane mold constraint has been done. Free volume theory has been used for the non-equilibrium density state by the fast cooling. At ejection, the redistribution of stress together with instantaneous deformation has been considered. During out-of-mold cooling after ejection, thermoelastic model based on the effective temperature has been adopted for the calculation of deformation. Two typical mold geometries are used to test the numerical simulation.

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Free Vibrations of Horizontally Curved Beams (수평 곡선보의 자유진동 해석)

  • Lee, Byoung-Koo;Oh, Sang-Jin
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1996.04a
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    • pp.151-156
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    • 1996
  • The differential equations governing free, out of plane vibrations of horizontally curved beams are derived and solved numerically to obtain the natural frequencies and the mode shapes. The Runge-Kutta method and Regula-Falsi method are used to integrate the differential equations and to determine the natural frequencies, respectively. In nu- merical examples, the hinged-clamped end constraint is considered and four lowest frequency parameters are reported as functions of four non-dimensional system parameters: (1) opening angle, (2) slenderness ratio, (3) shear parameter and (4) stiffness parameter. Also, typical mode shapes of displacements and stress resultants are shown.

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