• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.1
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• pp.29-37
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• 2007

This study deals with displacement analysis of anisotropic folded structures with triangular elements and quadrilateral elements. When folded plates are analyzed, triangular elements as well as quadrilateral elements are needed for conveniences of modelling. However, using triangular elements is not a simple problem. A simple formulation is presented which allows a quadrilateral element to degenerate into a triangular element. Therefore it can easily be used for computational simplicity and avoided complexities on mixed use of triangular element and quadrilateral element. In this paper, a high-order shear deformation theory using only Lagrangian interpolation functions and drilling degrees of freedom for folded plates are utilized for more accurate analysis. Especially, various results of anisotropic laminated and folded composite structures with triangular element and quadrilateral element show the structural behavior characteristics of them.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.1
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• pp.21-30
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• 2004

This study deals with free vibrations of laminated composite structures with a channel section using finite element method. In this paper, the mixed finite element method using Lagrangian and Hermite interpolation functions is adopted and a high-order plate theory is used to analyze laminated composite non-prismatic folded plates with a channel section more accurately for free vibration. The theory accounts for parabolic distribution of the transverse shear stress and requires no shear correction factors supposed in the first-order plate theory. An 32×32 matrix is assembled to transform the system element matrices from the local to global coordinates using a coordinate transformation matrix, in which an eighth drilling degree of freedom (DOF) per node is appended to the existing 7-DOF system. The results in this study are compared with those of available literatures for the conventional and first-order plate theory. Sample studies are carried out for various layup configurations and length-thickness ratio, and geometric shapes of plates. The significance of the high-order plate theory in analyzing complex composite structures with a channel section is enunciated in this paper.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.3 s.73
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• pp.223-231
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• 2006

This study deals with behavior characteristics of laminated composite folded structures according to ratio of folded length based on a higher-order shear deformation theory. Well-known mixed finite element method using Lagrangian and Hermite shape interpolation functions is a little complex and have some difficulties applying to a triangular element. However, a higher-order shear deformation theory using only Lagrangian shape interpolation functions avoids those problems. In this paper, a drilling degree of freedom is appended for more accurate analysis and computational simplicity of folded plates. There are ten degrees of freedom per node, and four nodes per element. Journal on folded plates for effects of length variations is not expressed. Many results in this study are carried out according to ratio of folded length. The rational design is possible through analyses of complex and unpredictable laminated composite folded structures.