• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.41-49
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• 2007

In general, the curved structures have the engineering efficiency as well as a fine view compared with straight member. Also, composite materials are composed of two or more different materials to produce desirable properties for structural strength as compared to single ones. Shell structures with composite materials have many advantages in strength and weight reduction. Therefore, composite laminated conical shells are analyzed in this study. To solve differential equations of conical shells, this paper used finite difference method. Various parametric study according to the change of radius ratio, vertex angle and subtended angle are examined. The change of radius ratio, vertex angle and subtended angle mean the change from conical shells to cylindrical shells, conical shells to circular plates and open shells closed shells, respectively.

• Structural Engineering and Mechanics
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• v.43 no.1
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• pp.89-103
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• 2012

In this study, the stability of laminated homogeneous and non-homogeneous orthotropic truncated conical shells with freely supported edges under a uniform hydrostatic pressure is investigated. It is assumed that the composite material is orthotropic and the material properties depend only on the thickness coordinate. The basic relations, the modified Donnell type stability and compatibility equations have been obtained for laminated non-homogeneous orthotropic truncated conical shells. Applying Galerkin method to the foregoing equations, the expression for the critical hydrostatic pressure is obtained. The appropriate formulas for the single-layer and laminated, cylindrical and complete conical shells made of homogeneous and non-homogeneous, orthotropic and isotropic materials are found as a special case. Finally, effects of non-homogeneity, number and ordering of layers and variations of shell characteristics on the critical hydrostatic pressure are investigated.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.4
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• pp.595-603
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• 1989

Free vibration of orthotropic laminated composite conical shells with constant thickness are considered. Governing frequency equations are derived based on the Flugge theory and Galerkin method is applied for the numerical analysis. Comparisons are made between present results and others for the isotropic conical shells and numerical results are obtained based on these results for the specially orthotropic laminated composite conical shells with simply supported edges. Variations of frequency parameter on the change of material properties, stacking sequences, stacking number, geometrical parameters and orthotropic parameters are considered in the analysis.

• Steel and Composite Structures
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• v.14 no.4
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• pp.397-408
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• 2013

This paper deals with multiobjective optimization of symmetrically laminated composite truncated circular conical shells subjected to external uniform pressure load and thermal load. The design objective is the maximization of the weighted sum of the critical buckling load and fundamental frequency. The design variable is the fibre orientations in the layers. The performance index is formulated as the weighted sum of individual objectives in order to obtain optimal solutions of the design problem. The first-order shear deformation theory (FSDT) is used in the mathematical formulation of laminated truncated conical shells. Finally, the effect of different weighting factors, length-to-radius ratio, semi-cone angle and boundary conditions on the optimal design is investigated and the results are compared.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.128-133
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• 2001

In this paper, stability analysis is carried out far the out of plane behaviors under compressive loads to the conical direction. It is not easy to obtain the analytic solutions about the stability analysis of anisotropic conical shells consisted of composite materials. For solving this problems, this paper used the finite difference method which is one of the numerical methods. The characteristics of the buckling behaviors of anisotropic laminated composite conical shells may be different according to a variety of causes, that is, the change of fiber angle, material arrangement, radius ratio, shape ratio and so on. The objective of this study is to analyze buckling behaviors of circular conical shells with shear deformation effects and to prove the advantage of composite materials.

• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.94-101
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• 2004

In this study, composite laminated conical shells with ring stiffeners are analyzed. A versatile 4-node shell element which is useful for the analysis of conical shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. The proposed element has six degrees of freedom per node and permits an easy connection to other types(beam element) of Optimum location and optimum section properties of ring stiffeners are obtained. It is shown that the thickness of conical shell is reduced about 20% by optimum ring stiffeners.

• Journal of Korean Society of Steel Construction
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• v.14 no.4
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• pp.519-527
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• 2002

Shell structures have become critical in the design of pressure vessels, submarine hulls, ship hulls, airplane structures, concrete roofs, containers for liquids, and many other structures. This study presented the feature of the free vibration of anisotropic laminated conical shells according to transverse shear deformation effects. Composite materials are composed of two or more different materials in order to produce desirable properties for structural strength. Since their behavior is very complex, it is almost impossible to solve the analytical solutions. This effects of subtended and vertex angles and other geometric parameters on vibration were investigated in a comprehensive parametric study. Selected vibration mode shapes were illustrated, to enable the physical understanding of vibration of laminated composite conical shells.

• Steel and Composite Structures
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• v.6 no.4
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• pp.353-366
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• 2006

The discrete singular convolution (DSC) algorithm for determining the frequencies of the free vibration of single isotropic and orthotropic laminated conical shells is developed by using a numerical solution of the governing differential equations of motion based on Love's first approximation thin shell theory. By applying the discrete singular convolution method, the free vibration equations of motion of the composite laminated conical shell are transformed to a set of algebraic equations. Convergence and comparison studies are carried out to check the validity and accuracy of the DSC method. The obtained results are in excellent agreement with those in the literature.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.2
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• pp.82-88
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• 2007

Thermal Buckling and free vibration analyses of multi-layered composite conical shells based on a layerwise displacement theory are performed. The Donnell's displacement-strain relationships of conical shell structure are applied. The natural frequencies are compared with the ones existing in the previous literature for laminated conical shells with several cone semi-vertex angles. Moreover, the thermal buckling behaviors of the laminated conical shell are investigated to consider the effect of the semi-vertex angle, subtended angle, and radius to thickness ratio on the structural stability.

• Computational Structural Engineering
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• v.8 no.3
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• pp.135-141
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• 1995

Any arbitrarily shaped laminated composite shells of revolution can be sum of the conical shell elements. Therefore, finite element model of conical shell element will be developed in this study. To verify consistency and validity of this model, natural vibrations of this model is compared with the analytical solution of cylindrical shell. Herein, an extensive parametric study is presented to assess the modeling capability of this model in class of laminated composite cylinders. It is seen that the proposed model provides highly accurate results with analytical solution. Once development of this conical shell element is done, any arbitrarily shaped composite shells of revolution can be easily analyzed.