• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.9-16
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• 2010

In this study, structural analyses were carried out on the composite sandwich panel which was tested under compression loading. In the structural analyses, three types of finite element modelling were considered and linear buckling analysis and nonlinear analysis were performed for each FE-model. Through the analyses, it was found that shell elements for face parts and solid elements for core part were appropriate for the better prediction of the buckling load of the panel. If the material failure of the face is critical than overall buckling of the sandwich panel, the use of one shell element through the thickness direction was suitable in the FE-model for the better predictions of failure location and failure load.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.3A
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• pp.457-464
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• 2006

Fiber-reinforced composite materials due to their high specific strength, high stiffness and light weight are becoming increasingly used in many engineering industry, especially in the aerospace, marin and civil, etc. In this paper, the buckling load and mode shapes of composite laminates with elliptical cross-section including transverse shear deformations are analyzed. For solving this problems, a versatile flat shell element has been developed by combining a membrane element with drilling degree-of-freedom and a plate bending element. Also, an improved shell element has been established by the combined use of the addition of enhanced assumed strain and the substitute shear strain fields. The combined influence of shell geometry and elliptical cross-sectional parameter, fiber angle, and lay-up on the buckling loads of elliptical cylinder is examined. The critical buckling loads and mode shapes analyzed here may serve as a benchmark for future investigations.

• Computational Structural Engineering
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• v.6 no.1
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• pp.117-125
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• 1993

In general, the strength and stiffness of laminated composite cylindrical shells are very sensitive to the variation of slenderness parameters, some coupling-stiffness parameters, lamination angles, stacking sequence and number of layers. In this paper, the effects of these factors on the strength and buckling reliabilities of GFRP laminated cylindrical shells are investigated based on the proposed strength and buckling limit state models. As these factors have various and complicated effects on the strength and buckling reliabilities of GFRP laminated cylindrical shells, the results should be incorporated into the design formula such that optimum design technique and design code which provide uniform consistent reliability for balanced design in practice

• Composites Research
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• v.27 no.4
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• pp.158-167
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• 2014

Final goal of this research is to establish the database for correlation factors which connects the test and analysis results of shear buckling allowables for composite plate. To accomplish the goal, extensive test and analysis works are required. In this paper, as the first step, a frame-type fixture for shear buckling test was designed and validated through the test and analysis. Final configuration of the fixture were determined via parametric study on the effect of specimen size, cross-sectional dimensions, and number of fastening bolts on the shear buckling load. Results of the study showed the designed frame-type fixture successfully induces the shear buckling of composite plate. However, there were deviations between the test results and analysis results for ideal case under pure shear load, which were mainly caused by the difference in plate sizes for both cases. The difference were larger in the plates with larger hole and simply supported boundary condition. It is concluded from the results that while the designed fixture can be used for the clamped plates with acceptable accuracy, it shows larger difference in the simply supported plates.

• Composites Research
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• v.24 no.4
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• pp.17-22
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• 2011

In this paper, as a basic research to apply the composite sandwich to underwater vehicle, the manufacturing, analysis and test methods, and weight saving effect of a composite sandwich cylinder under external pressure were studied. A two-step manufacturing method to prevent the wrinkling of the sandwich cylinder face was proposed and the three cylinders were made and tested. Finite element results based on the shell and solid model using MSC.Nastran were compared with test results. The comparison showed that the linear finite element analysis using the shell and solid elements can predict the buckling pressure of the sandwich cylinder with approximately 3% difference. The parametric study of the filament wound cylinders revealed that the composite sandwich can reduce the weight of the cylinder more than 30% compared with the filament wound cylinder supporting the same pressure.

• The magazine of the Korean Society for Advanced Composite Structures
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• v.5 no.1
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• pp.10-12
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• 2014

• Composites Research
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• v.13 no.5
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• pp.37-43
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• 2000

In this paper an analytical investigation pertaining to the elastic shear buckling behavior of transversely stiffened orthotropic plate under in-plane shear forces is presented. All edges of plate are assumed to be simply supported and the evenly placed stiffener is considered as a beam element neglecting its torsional rigidity. For the solution of the problem Rayleigh-Ritz method is employed. Using the derived equation, the limit of buckling stress of transversely stiffened plate is suggested as a graphical form. Based on the limit of buckling stress of stiffened plate, graphical form of results for finding the required stiffener rigidity is presented when one and two stiffeners are located, respectively.

• 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.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.04a
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• pp.217-220
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• 1999

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.04a
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• pp.221-225
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• 1999