• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2001.11a
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• pp.349.2-363
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• 2001

안전성의 측면에서 기계설비 및 구조물의 파손을 유발할 수 있는 재료손상에 대한 평가는 매우 중요하기 때문에, 사용 목적에 부합되는 우수한 첨단재료의 개발과 그 특성을 파악할 필요성이 있다 그 중에서 섬유강화 복합재료는 금속재료보다 높은 비강도와 비강성을 가지며 적층각도, 적층순서 및 경화방법에 따라서 원하는 강도와 강성을 가질 수 있다 특히, 탄소섬유강화복합재료(CFRP)는 스포츠용품에서 최신 항공기의 구조재료에 이르기까지 경량화 관점에서 기존의 재료를 대체해 나가고 있다.(중략)

• Composites Research
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• v.13 no.2
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• pp.8-21
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• 2000

In th is paper. the low degree of homogeneity issue in the effective modulus was studied for plain weave textile composites. Unit cell analyses were performed using multi-field macroelements. The effective moduli were calculated for finite and infinite configurations and the statistics assessment of the results was presented. Results indicated that the effective modulus of plain weave textile composites depended strongly on the fiber tow phase shift angles and the number of layers. As the number of layers increased, however, the distribution of the modulus showed concentration and higher degrees of homogeneity was attained.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.6 no.1
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• pp.10-15
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• 2015

• The magazine of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.31-37
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• 2011

• The magazine of the Korean Society for Advanced Composite Structures
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• v.5 no.4
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• pp.16-20
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• 2014

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1998.10a
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• pp.19-19
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• 1998

라이너를 포함한 필라멘트 와인딩 복합재 압력용기의 성능향상을 위한 효율적인 구조최적 설계방안을 제시하였다. 이를 위해 온도효과가 고려된 비선형 유한요소법을 이용하여 각 층에서의 응력해석과 파손해석을 수행하였다. 또한 설계변수로 라이너의 두께와 헬리컬 적층두께, 실린더를 따라 변하는 직각 적층두께를 설정하였다. 모든 설계변수들에 대한 강도비 민감도를 유도하였으며 헬리컬 적층두께에 대한 강도비 민감도를 유지하기 위해 측지 등장력 돔설계 방법을 고려하였다. 구조 최적설계결과, 실린더를 따라 직각 적층두께를 최적으로 분포시켜 강성을 효과적으로 배열하였으므로 적층두께를 일정하게 고려한 경우보다 더 경량화 시킬 수 있었다.

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.1
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• pp.29-34
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• 2012

Even though the longitudinally stiffened laminated composite plates with closed section ribs should be an effective system for axially compressed members, the existing researches on the applications of closed-section ribs, especially for the laminated composite plates, are not sufficient. This study is aimed to examine the influence of the sectional stiffness of U-shaped ribs on the buckling modes and strengths of laminated composite plates. Applying the orthotropic plates with eight layers of the layup $[(0^{\circ})_4]_s$ and $[(0^{\circ}/90^{\circ})_2]_s$, 3-dimensional finite element models for the U-rib stiffened plates were setup by using ABAQUS and then a series of eigenvalue analyses were conducted. From the parametric studies, the minimum required ply thicknesses as well as the buckling strengths were presented for the analysis models. The buckling strengths were compared with the theoretical critical stress equation for simply supported plates based on the Classical laminated plate theory. This study will contribute to the future study for evaluating the minimum required stiffness and optimum design of U-rib stiffened plates.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.497-502
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• 2015

In this paper, a stress function-based approach was proposed to analyze the reduction of free-edge peeling stress in smart composite laminates using piezoelectric actuator under bending load. Electro-mechanically coupled governing equation was obtained by complimentary virtual work principle. The stress state was solved by the generalized eigenvalue procedure. The free-edge peeling stress of smart composite laminates was reduced by the piezoelectric actuation. The reduction rate of peeling stress in cross-ply composite laminate is larger than that in angle ply composite laminate.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.3
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• pp.299-308
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• 2001

This paper presents the three-dimensional (3-D) study of the natural vibration of cantilevered laminated composite plates. The Ritz method is used to obtain stationary values of the associated Lagrangian functional with displacements approximated by mathematically complete polynomials satisfying the boundary conditions at the clamped edge exactly. The accuracy of the 3-D model is established through a convergence study of non-dimensional frequencies followed by a comparison of the converged 3-D solutions with analytical and experimental findings in the existing literature. A wide scope of 3-D frequency results explain the influence of a number of geometrical and material parameters for cantilevered laminated plates, namely aspect ratio (a/b), width-to-thickness ratio (a/h), orthotropy of material, number of plies (NP), fiber orientation angle(θ), and stacking sequence.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.1
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• pp.37-44
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• 1999

비등방성으로 적층된 복합판 및 쉘구조물에서 온도와 습도의 급격한 변화는 구조물의 강도와 성능을 저하시키는 중요한 원인이 된다. 더욱이 하중에 의한 역학적 변위와 조합될 때에는 좌굴, 대변형 혹은 고응력 상태를 유발하게 된다. 본 연구에서는 이중 퓨리에급수를 이용하여 3차의 전단변형함수로 가정된 평형방정석을 전개하고 폭-두께비, 형상비의 변화 그리고 재료의 성질에 따른 결과에 대하여 고찰하였다.