• Title, Summary, Keyword: 적층배열

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A Study on the Improvement Buckling Strength of Laminated Composite Plate by Taguchi Method (다구찌법을 이용한 복합적층판의 좌굴강도 개선에 관한 연구)

  • 구경민;홍도관;김동영;박일수;안찬우;한근조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1362-1365
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    • 2003
  • On this study. we improved the efficiency applying algorithm that is repeatedly using orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized buckling strength of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result optimization achievement repeatedly using statistical orthogonal array of experimental design.

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Vibration Control of Cantilevered Structures Laminated of fiber-reinforced Composite Materials (섬유강화 복합재료 적층 구조물 (외팔보형태)의 면진 및 제진)

  • 오동훈
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.67-72
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    • 1995
  • 본 연구에서는 섬유강화 복합재료로 구성된 항공기 날개를 외팔보 형태 구조물로 모델링하고 동특성 해석을 위해 횡전단변형 이론과 고전 적층판 이론을 적용, Rayleigh-Ritz 방법에 의한 진동해석을 수행한뒤 진동 발생시 효과적으로 제어할 수 있는 방법을 제시하고 시뮬레이션을 통하여 동특성 향상을 정량적으로 제시하였다. 진동을 제어하기 위한 방법으로서 수동적, 능동적 방법을 모두 사용하고 있는데, (보다 자세한 사항은 참고문헌[12] 참조) 본 연구에서는 TMD(Tuned Mass Damper)를 사용하지 않고 복합소재 구조물의 성질을 이용한 탄성배열설계(Structural Tailoring)로 수동적 의미의 면진효과를 거둘 수 있게 하였다. 능동 제어의 경우 되먹임(feedback) 제어기를 이용, 이산(discret) 작동기(actuator)를 통하여 외팔보의 휨 및 비틀림 모우드를 함께 제어하여 효과적인 제어기를 설계하였다.

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Failure strength of machined composite edges under shear load (전단하중하의 복합재료 모서리의 파괴강도)

  • 이재광;황병선;박승범;윤한기;박인서
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.96-99
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    • 2001
  • Strength and manufacturing characteristics were evaluated in this paper. It depends on lay-up type and fiber direction when the fiber/resin composites have specific notch shapes. Unique jig and fixture were designed and used to test laminated specimens with notches. From the result of uni-direction specimen test we try to predict strength of multi-direction specimen by FEA.

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A study on fatigue life of Al 7075/CFRP multilayered hybrid composite materials (Al 7075/CFRP 다적층 하이브리드 복합재료의 피로수명에 대한 연구)

  • 윤한기;김연겸;박준수;이경봉
    • Journal of Ocean Engineering and Technology
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    • v.10 no.4
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    • pp.92-102
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    • 1996
  • In this research, to develope the A1 7075/CFRP multilayered hybrid composites, CRALL(Carbon Reinforced aluminum lamiate) specimens were processed by autoclavecuring system that curing temperature, time, surface pretreatment condition of aluminum were constant. Andthe fatigye life and failure mechanism on CFRP volume fraction and fiber orientation of CRALLspecimens were investigated. A fatigue life was greatly influenced by effect of CFRP fiber volume fraction but it was less effected than those of fiber orientation. The fatigue failure arised from interface delamination of CFRP and aluminum sheet after shear fracture of aluminum layer. The failure mechanism is assumed that the aluminum laminates which divide the CFRP into many thim layers tend to arrest the failure propagation.

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Three Dimensional Interlaminar Stress Analysis of a Composite Patch Using Stress Functions (응력함수를 이용한 복합재 적층 패치의 3차원 층간 응력 해석)

  • Lee, Jae-Hun;Cho, Maeng-Hyo;Kim, Heung-Soo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.488-491
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    • 2009
  • 본 논문에서는 응력함수와 Kantorovich method를 이용하여 기저판(substrate)에 인장과 굽힘이 작용할 때 복합재 패치의 3차원 응력을 해석하였다. 면내 방향과 면외 방향의 두 응력함수에 가상 공액일의 법칙(Complementary virtual work principle)을 적용하였으며 복합재 패치의 자유 경계조건과 바닥의 기저판으로부터 전달되는 전단 수직 응력 조건을 부여하였다. 이를 통해서 패치 구조물의 지배방정식을 연립 미분 방정식 형태의 고유치 문제로 변환하여 응력함수를 구하였다. 위 방법의 타당성과 효용성을 검증하기 위한 수치 예제로 cross-ply, angle-ply, quasi-isotropic의 패치 적층 배열을 고려하였으며, 층간 응력함수 값이 자유 경계에서 최고치를 나타내고 패치 중심부로 갈수록 급격히 감소하는 모습을 확인하였다. 제안된 기법은 기저판에 인장하중이 작용하는 경우뿐만 아니라 굽힘 하중이 작용하는 경우에도 정확한 예측이 가능하여, 패치 구조물의 층간 응력을 포함한 3차원 응력을 해석하는데 있어서 효율적인 해석 도구로서 사용할 수 있을 것이라 사료된다.

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Geometrical nonlinear dynamic analysis of laminated skew plates made of advanced composite materials (적층된 ACM 경사판의 기하학적 비선형 동적 해석)

  • Lee, Sang-Youl;Chang, Suk-Yoon
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.1 no.4
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    • pp.28-34
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    • 2010
  • W e performed a geometrical nonlinear dynamic analysis 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 skew angles and layup 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 and skew plates, and the new results reported in this paper show the significant interactions between the skew angle and layup sequence in the skew laminate. Key observation points are discussed and a brief design guideline is given.

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Shape Optimization of Laminated Composite Shell for Various Layup Configurations (적층배열에 따른 복합재료 쉘의 형상최적화)

  • 김현철;노희열;조맹효
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.317-324
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    • 2004
  • Shape design optimization of shell structure is implemented on a basis of integrated framework of geometric modeling and finite element analysis which is constructed on the geometrically exact shell theory. This shell theory enables more accurate and robust analysis for complicated shell structures, and it fits for the nature of B-spline function which Is popular modeling scheme in CAD field. Shape of laminated composite shells is optimized through genetic algorithm and sequential linear programming, because there ire numerous optima for various configurations, constraints, and searching paths. Sequential adaptation of global and local optimization makes the process more efficient. Two different optimized results of laminated composite shell structures to minimize strain energy are shown for different layup sequence.

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Design of an HTS Magnet for a 2.5 MJ SMES (2.5 MJ SMES용 고온초전도 마그넷 설계)

  • Lee, Se-Yeon;Kwak, Sang-Yeop;Kim, Young-Il;Kim, Woo-Seok;Lee, Ji-Kwang;Park, Chan;Choi, Kyeong-Dal
    • Proceedings of the KIEE Conference
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    • pp.631-632
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    • 2008
  • 본 논문은 2.5MJ의 저장용량을 가지는 SMES 용 고온초전도 마그넷의 설계에 관한 연구 결과이다. 선재는 2세대 고온초전도 선재인 YBCO CC를 2단으로 적층하여 사용하였다. 운전전류는 전도냉각 방식을 사용하는 것을 가정해 22K의 운전온도에서 선재의 임계전류를 고려하여 600A 이상으로 결정하였다. 마그넷의 형상은 싱글 솔레노이드와 토로이드 형태로 각각 설계하였고 싱글 솔레노이드는 더블 팬케이크 모듈코일을 적층하여 구성 토로이드는 싱글팬케이크 모듈코일을 배열하여 모듈러 토로이드로 구성하였다. 각 형상별 설계결과를 통해 저장에너지와 선재사용량 그리고 누설자장의 크기를 각각 비교하였다.

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Buckling and Vibration Analysis of Antisymmetric Angle-ply laminated Composite Plates using a Three-dimensional Higher-order Theory (3차원 고차이론을 이용한 역대칭 앵글-플라이를 갖는 복합재료 적층판의 좌굴 및 진동해석)

  • Lee, Won Hong;Han, Sung Cheon;Chun, Kyoung Sik;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.15 no.2
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    • pp.97-107
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    • 2003
  • To obtain a more accurate response from larninated composite structures, the effect of transverse shear deformation, transverse normal strain/stress, and nonlinear variation of in-plane displacements vis-$\\grave{a}$-vis the thickness coordinate should be considered in the analysis. The improved higher-order theory was used to determine the critical buckling load and natural frequencies of laminated composite structures. Solutions of simply supported laminated composite plates and sandwiches were obtained in closed form using Navier's technique, with the results compared with calculated results using the first order and other higher-order theories. Numerical results were presented for fiber-reinforced laminates, which show the effects of ply orientation, number of layers, side-toithickness ratio, and aspects ratio.

A Practical Method of Acoustic Emission Source Location in Anisotropic Composite Laminates (이방성 적층복합재 구조에서 AE 발생원 위치표정을 위한 실용적인 방법)

  • Kim, Jeong-Kon;Kang, Yong-Kyu;Kwon, Oh-Yang
    • Journal of the Korean Society for Nondestructive Testing
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    • v.23 no.3
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    • pp.237-245
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    • 2003
  • Since the velocity is dependent on the fiber orientation in anisotropic composites, the application of traditional acoustic emission (AE) source location techniques based on the constant velocity to composite structures has been practically impossible. The anisotropy makes the source location procedure complicated and deteriorates the accuracy of the location. In this study, we have divided the region of interest(ROI) into a set of finite elements, taken each element as a virtual source, and calculated the arrival time differences between sensors by using the velocities at every degree from 0 to 90. The calculated and the experimentally measured values of the arrival time difference aye then compared to minimize the location error. The results from two different materials, namely AA6061-T6 and CFRP(uni-directional; UD, $[0]_{32}4$) laminate confirmed the practical usefulness of the proposed method.