• Journal of the Computational Structural Engineering Institute of Korea
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• 제22권2호
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• pp.189-196
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• 2009

This paper presents the subparametric finite element model formulated by partial-linear layerwise theory for the analysis of laminate composites. The proposed model is based on refined approximations of two dimensional plane for orthotropic thick laminate plate as well as thin case. Three dimensional problem can be reduced to two dimensional case by assuming piecewise linear variation of in-plane displacement and a constant value of out-of-plane displacement across the thickness. The integrals of Legendre polynomials are chosen to define displacement fields and Gauss-Lobatto numerical integration is implemented in order to directly obtain maximum values occurred at the nodal points of each layer without other extrapolation techniques. The validity and characteristics of the proposed model have been tested by using orthotropic multilayered plate problem as compared to the values available in the published references. In this study, the convergence test has been carried out to determine the optimal layer model in terms of central deflection and stresses. Also, the distribution of displacements and stresses across the thickness has been investigated as the number of layer is increased.

• Transactions of the Korean Society of Mechanical Engineers
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• 제15권3호
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• pp.735-750
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• 1991

본 연구에서는 적층 복합판의 충격 해석을 위하여 Reddy의 고차 전단 변형 이 론에 기초를 두고, 정적 압입 실험에 의한 접촉 법칙을 고려한 동적 유한 요소 해석 (dynamic finite element analysis)을 행하여 충격 실험에 의한 결과와 1차 전단변형 이론에 의한 해와 비교 검토하므로서, 그 유용성과 우수성을 입증하고, 적층 복합재의 충격 응력 및 응력파 전파 특성에 대하여 연구하고자 한다.

• The magazine of the Korean Society for Advanced Composite Structures
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• 제5권3호
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• pp.15-25
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• 2014

• KSCE Journal of Civil and Environmental Engineering Research
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• 제31권6A호
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• pp.409-415
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• 2011

Optimization Analysis of angle-ply laminated shells, having one pair of opposite edges supported, are investigated on the basis of the first-order shear deformation theory. The equations of motion of the shell are solved by the use of ritz method. A range of results are presented for composite shells to show the effects of lamination angle and number of layers on natural frequency. In addition, an analysis of the strain energy distributions is used as an aid for the better understanding of the vibration characteristics of the shells.

• Journal of Aerospace System Engineering
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• 제16권5호
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• pp.35-42
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• 2022

This paper deals with predicting comparable mechanical properties of laminated composite plates. The stiffness of an equivalent anisotropic composite plate is derived based on classical lamination theory. A novel failure criterion is defined to describe the failure behaviour of laminated composite plates based on micro-mechanics failure criteria. Finally, the theory's validation of finite element analysis results was verified. We concluded that this theory is very suitable for failure analysis of laminated composite plates for aerospace applications due to their relative simplicity and computational efficiency.

• Transactions of the Korean Society of Mechanical Engineers
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• 제12권4호
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• pp.652-661
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• 1988

A theoretical attempt is made to analyze the dynamic contact force and response of laminated composite beams subjected to the transverse impact of steel balls. A beam finite element model based on the modified theory for laminated composites in conjunction with static contact laws is formulated for the theoretical investigation. Finally, it is shown that the present results are in good agreement with some existing solutions or wave propagation theory.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제30권3호
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• pp.115-122
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• 2002

구조감쇠가 복합적층판의 초음속 패널 플러터에 미치는 영향을 연구하기 위해 에너지법을 활용하여 지배방정식을 유도하였다. 구조 모델링은 일반적인 고전 적층판 이론을 적용하고 이의 해석은 진동 모우드를 가정하는 Rayleigh-Ritz법을 이용하였다. 비정상 공기력은 피스톤 이론(piston theory)을 적용하였다. 구조감쇠가 패널의 플러터에 미치는 일반적인 영향을 고찰하기 위해 등방성 평판의 구조감쇠의 크기에 따른 임계동압을 계산하였으며 이로부터 구조감쇠가 플러터 안정성을 감소시킬 수 있음을 확인하였다. 또한 복합적층판의 적층각에 따른 임계동압을 계산하여 패널 플러터와 구조감쇠와의 관계를 파악하였다. 구조감쇠는 낮은 공력감쇠에서는 플러터 안정성에 중요한 역할을 하지만 높은 공력감쇠에서는 거의 영향을 미치지 않았다.

• Proceeding of KASS Symposium
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• 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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• pp.95-100
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• 2008

A 4-node assumed strain finite element based on higher order shear deformation theory is developed to investigate the behaviours of symmetric and unsymmetric laminated composite plates. The present element is based on Reddy's higher order shear deformation theory so that it can consider the parabolic distribution of shear deformation through plate thickness direction. In particular, assumed strain method is adopted to alleviate the shear locking phenomena inherited plate elements based on higher order shear deformation theory. The present finite element has seven degrees of freedom per node and denoted as HSA4. Numerical examples are carried out for symmetric and unsymmetric laminated composite plate with various thickness values. Numerical results are compared with reference solutions produced by other higher order shear deformation theories.

• Journal of Korean Society of Steel Construction
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• 제9권4호통권33호
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• pp.601-609
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• 1997

Bending and vibration results for a laminated plate base on a simplified higher-order plate theory with four variables are presented. Assuming a constant in-plane rotation tensor through the thickness in Reddy's higher-order shear deformation theory it is shown that a simpler higher-order theory can be obtained with the reduction of one variable without significant loss in the accuracy. This simple higher-order shear deformation theory is then used for predicting the natural frequencies and deflection of simply-supported laminated composite plates. The results obtained for antisymmetrical laminated composite plates compare favorably with third-order and first-order shear deformation theory. The information presented should be useful to composite-structure designers, to researchers seeking to obtain better correlation between theory and experiment and to numerical analysts in checking out their programs.

• Composites Research
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• 제25권5호
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• pp.141-146
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• 2012

The strength design for the lightweight bicycle wheel made of the Carbon/Epoxy composite laminates has been discussed in this paper. For bicycle wheel design, lightness of the wheel is important. Also, it has to satisfy the required strength under specific loading cases. Two testing methods for the bicycle wheel, i.e. vertical and complex loadings, are adopted in this study. Because the strengths of composite wheel is different in relation to the stacking sequence and the number of plies, it is important to decide an appropriate stacking sequence and number of layers for the composite wheel. From the finite element analysis results, the most stable sequence orientation and number of layers are determined. The stacking sequence $[0]_{8n}$, $[90]_{8n}$, $[0/90]_{2ns}$, $[{\pm}45]_{2ns}$, $[0/{\pm}45/90]_{ns}$ (n=1,2,3,4)are performed for finite element analysis. From results, $[0/{\pm}45/90]_{3s}$ lay-up is a good selection for the composite bicycle wheel. Also, the weakest point and layer are found in this study.