• Title, Summary, Keyword: 적층배열

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Characteristics of Magnetization Loss in BSCCO Multi-stacked Conductor According to Stacking Geometry using 2-D FEM (수치해석을 이용한 적층 배열에 따른 BSCCO 적층선재의 자화손실 특성)

  • Park, Myung-Jin;Lee, Kwang-Youn;Cha, Guee-Soo;Lee, Ji-Kwang
    • Proceedings of the KIEE Conference
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    • pp.945-947
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    • 2005
  • 변압기, 케이블, 한류기와 같은 고온초전도 선재의 전력기기의 개발과 응용에 있어서 교류손실은 기기의 운용과 효율에 밀접한 관계가 있기 때문에 중요한 연구 분야가 되고 있다. 또한 현재 전력기기에 응용 하고 있는 고온초전도 선재는 전력기기에 필요한 통전용량을 수용 할 수 없기 때문에 이를 해결하기 위한 방법으로 선재를 적층하여 통전용량을 증대시키는 다양한 방법이 연구되고 있다. 본 논문에서는 고온초전도 선재의 적층배열을 달리 하였을 때, 외부자계에 의한 고온초전도 선재의 자화손실 특성에 대해서 연구하였다. 선재의 적층 배열의 형상은 Edge-to-Edge, Face-to-Face형과 Matrix형이며, 적층배열에 사용한 선재의 개수는 2, 4, 8개이다. 연구결과, 동일한 적층 수의 조건하에서 Face-to-Face형의 적층배열이 다른 종류의 배열보다 자화손실이 낮음을 확인하였고, 이는 Face-to-Face 형태로 적층 될 때 인접선재로 인한 자기차폐효과가 다른 배열의 경우보다 우수하기 때문으로 보인다.

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Determination of Degraded Properties of Vibrating Laminated Composite Plates for Different Layup Sequences (적층배열 변화에 따른 진동하는 복합재료 적층 구조의 미시역학적 물성변화 추정)

  • Kim, Gyu-Dong;Lee, Sang-Youl
    • Composites Research
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    • v.28 no.5
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    • pp.277-284
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    • 2015
  • This paper presents a method to detect the fiber property variation of laminated GFRP plates from natural frequency response data. The combined finite element analysis using ABAQUS and the inverse algorithm described in this paper may allow us not only to detect the deteriorated elements from the mirco-mechanical point of view but also to find their numbers, locations, and the extent of damage. To solve the inverse problem using the combined method, this study uses several natural frequencies instead of mode shapes in a structure as the measured data. Several numerical results show that the proposed system is computationally efficient in identifying fiber stiffness degradation for complex structures such as composites with various layup sequences.

Parametric effects on geometrical nonlinear dynamic behaviors of laminated composite skew plates (적층된 복합소재 경사판의 기하학적 비선형 동적 거동에 미치는 매개변수 영향)

  • Lee, Sang-Youl
    • Composites Research
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    • v.25 no.6
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    • pp.217-223
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    • 2012
  • This study investigates a geometrical nonlinear dynamic behaviors of laminated skew plates made of advanced composite materials (ACM). Based on the first-order shear deformation plate theory (FSDT), the Newmark method and Newton-Raphson iteration are used for the nonlinear dynamic solution. The effects of cutout sizes, skew angles and lay up sequences on the nonlinear dynamic response for various parameters are studied using a nonlinear dynamic finite element program developed for this study. The several numerical results were in good agreement with those reported by other investigators for square composite plates with or without central cutouts, and the new results reported in this paper show the significant interactions between the cutout, skew angles and layup sequence in the laminate. Key observation points are discussed and a brief design guideline of skew laminates is given.

Design of Three-stacked Microstrip Patch Array Antenna Having Tx/Rx Feeds For Satellite Communication (위성통신을 위한 송수신 겸용 삼중 적층 마이크로스트립 패치 배열 안테나 설계)

  • Park, Ung-Hee;Noh, Haeng-Sook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.5
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    • pp.853-859
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    • 2007
  • This paper presents a microstrip patch array antenna having transmission feed and reception feed for satellite communication in the Ku band. In this paper, the element of the patch array antenna is a three-stacked structure consisting of one radiation patch and two parasitic patches for high gain and wide bandwidth characteristics. To obtain higher gain, the unit elements are expanded into a $1{\times}8$ may using a mixture of series and parallel feeds. The proposed antenna has horizontal polarization for the Rx band and vertical polarization for the Tx band. To verify the practicality of this antenna, we fabricated a three-stacked patch array antenna and measured its performance. The gain of the array antenna in the Rx and Tx bands exceeds 17 and 18 dBi, respectively. The impedance bandwidth is over 10 % in both bands. The cross-polarization level is below -25 dB, and the sidelobe level is below -9.4 dB.

Finite Difference Nonlinear Analysis of Composite Plate Structures with Various Layer Sequences (다양한 적층 배열을 갖는 복합 신소재 판 구조물의 유한차분 비선형 해석)

  • Lee, Sang Bum;Lee, Sang Youl;Lee, Rae Chul
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.4
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    • pp.159-168
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    • 2005
  • This study carries out a finite difference nonlinear analysis of anisotropic advanced composite plate structures with various layer sequences. In the numerical analysis of various mechanical problems involving complex partial differential equations, the finite difference method (FDM) developed in this study has an advantage over the finite element method in its ability to avoid mesh generation and numerical integration. Many studies in FDM have been made on clamped or simple boundary conditions using merely an energy approach. These approaches cannot be satisfied, however, with pivotal points along the free boundary. Therefore, this study addresses the nonlinear problem of anisotropic plates by adopting a finite difference modeling elimination of pivotal difference points in the case of a free boundary condition. Complex nonlinear behaviors of composite plate structures for various parameters, especially for layer sequences, are analyzed using the proposed approach.

A Design of X-Band Microstrip Array Antenna (X대역 마이크로스트립 배열 안테나)

  • Kim, Min-Joon;Cheon, I-Hwan;Kim, Ju-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.5
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    • pp.860-867
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    • 2009
  • In this paper, we designed the array antenna for FMCW radar in X - band frequency, and we chose stacked structure for improvement of narrow bandwidth. The array antenna is implemented on the circuit board which is relative permittivity 2.33 and the stacked patchs are designed on the circuit board which is relative permittivity 4.6. A Foam which has a similar permittivity of air is added to keep the particular gap between array antenna and the stacked patch. The result of array antenna has characteristics that a half-power beam width is $10.6^{\circ}$ and antenna gain is 18.70 dBi and bandwidth is 1.25GHz at the design frequency of 9GHz. The result of the array antenna with the stacked structure has that the half power beam width is $15.17^{\circ}$ and the antenna gain is 15.85dBi and bandwidth is 2GHz. It is needed to improve the antenna gain as keeping bandwidth in same level.

Nonlinear Dynamic Behaviors of Laminated Composite Structures Containing Central Cutouts (중앙개구부를 갖는 복합신소재 적층 구조의 비선형 동적 거동)

  • Ji, Hyo-Seon;Lee, Sang-Youl
    • Journal of Korean Society of Steel Construction
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    • v.23 no.5
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    • pp.607-614
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    • 2011
  • This study deals with thegeometrical nonlinear dynamic behavior of laminated plates made of advanced composite materials (ACMs), which contain central cutouts. Based on the first-order shear deformation plate theory (FSDT), the Newmark method and Newton-Raphson iteration wereused for the nonlinear dynamic solution. The effects of the cutout sizes and lay-up sequences on the nonlinear dynamic response for various parameters werestudied using a nonlinear dynamic finite element program that was developed for this study. The several numerical results agreed well with those reported by other investigators for square composite plates with or without central cutouts, and the new results reported in this paper showed significant interactions between the cutout and the layup sequence in the laminate. Key observation points are discussed and a brief design guide for laminates with central cutouts is given.

Natural Frequency and Mode Characteristics of Composite Pole Structures for Different Layup Sequences (복합소재 기둥 구조의 적층배열 변화에 따른 고유진동 및 모드 특성)

  • Kim, Gyu-Dong;Rus, Guillermo;Lee, Sang-Youl
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.4 no.1
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    • pp.9-14
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    • 2013
  • The dynamic analysis of poles made of advanced composite materials is carried out for different length-thickness ratios and layup sequences. The numerical results using ABAQUS obtained for plates and shells are in good agreement with those reported by other investigators. The new results for laminated composite pole structures in this study mainly show the effect of the interactions between the radius-length ratio and other various parameters. The effect of fiber angles of long composite poles also investigated. Key observation points are discussed and a brief design guideline is given.

Determination of Degraded Fiber Properties of Laminated CFRP Flat Plates Using the Bivariate Gaussian Distribution Function (이변량 Gaussian 분포함수를 적용한 CFRP 적층 평판의 보강섬유 물성저하 규명)

  • Kim, Gyu-Dong;Lee, Sang-Youl
    • Composites Research
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    • v.29 no.5
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    • pp.299-305
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    • 2016
  • This paper presents a method to detect the fiber property variation of laminated CFRP plates using the bivariate Gaussian distribution function. Five unknown parameters are considered to determine the fiber damage distribution, which is a modified form of the bivariate Gaussian distribution function. To solve the inverse problem using the combined computational method, this study uses several natural frequencies and mode shapes in a structure as the measured data. The numerical examples show that the proposed technique is a feasible and practical method which can prove the location of a damaged region as well as inspect the distribution of deteriorated stiffness of CFRP plates for different fiber angles and layup sequences.