• Journal of KSNVE
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• v.9 no.3
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• pp.485-492
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• 1999

The effects of boundary conditions on vibration characteristics for the ring stiffered composite cylindrical shells are investigated by theoretical and experimental method. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect are adopted to derive the frequency equation. In experiment, the impact exciting method is used to obtain the vibraton results. Five different boundary conditions: clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.359-364
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• 1998

The effects of boundary conditions on natural frequencies for the ring stiffened composite cylindrical shells are investigated by theoretical method. The Love's thin shell theory and the discrete stiffener theory with beam functions in the Ritz procedure are used to derive the frequency equation. Five different boundary conditions such as clamped-clamped, simply supported-simply supported, free-free, clamped-free, clamped-simply supported are considered in this study. Also, the experimental investigation is presented to validate the theoretical results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.11
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• pp.1802-1812
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• 2001

The theoretical method is developed to investigate the effects of ring stiffeners on free vibration characteristics and transient response for the ring stiffened composite cylindrical shells subjected to the impulse pressure Loading. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect is adopted to formulate the theoretical model. The concentric or eccentric ring stiffeners are laminated with composite and have the uniform rectangular cross section. The modal analysis technique is used to develop the analytical solutions of the transient problem. The analysis is based on an expansion of the loads, displacements in the double Fourier series that satisfy the boundary conditions. The effect of stiffener's eccentricity, number, size, and position on transient response of the shells is examined. The results are verified by comparison with FEM results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.349-354
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• 1996

The analytical solutions for the free vibration and buckling of cross-ply laminated composite cylindrical shell with axial stiffeners(stringers) and circumferential stiffeners(rings), that is, orthogonally stiffened shells, are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.883-888
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• 2001

The theoretical method is developed to investigate the effects of ring stiffeners on free vibration characteristics and transient response for the ring stiffened composite cylindrical shells subjected to the impulse pressure loading. In the theoretical procedure, the Love's thin shell theory combined with the discrete stiffener theory to consider the ring stiffening effect is adopted to formulate the theoretical model. The concentric or eccentric ring stiffeners are laminated with composite and have the uniform rectangular cross section. The modal analysis technique is used to develop the analytical solutions of the transient problem. The analysis is based on an expansion of the loads, displacements in the double Fourier series that satisfy the boundary conditions. The effect of stiffener's eccentricity, number, size, and position on transient response of the shells is examined. The theoretical results are verified by comparison with FEM results.

• Journal of KSNVE
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• v.6 no.4
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• pp.457-467
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• 1996

The analytical solutions for the free vibration and buckling of cross -ply laminated composite cylindrical shell with the orthogonal stiffeners, i. e., axial stiffeners(stringers) and circumferential stiffeners(rings), are presented using the energy method. The stiffeners are assumed to be an integral part of the shell and have been directly included in analysis(it's called discrete stiffener theory). The effect of the parameters such as the stacking sequences, the shell thickness, the shell length-to-radius ratio are studied. By comparison with the previously published analytical results for the stiffened cylindrical shells, it is shown that natural frequencies can be determined with adequate accuracy.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.61-71
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• 2017

The flexural behavior of composite ring stiffened by GFRP and steel pipe is presented in this paper. The effective width is required to construct FEM beam element model to verify the composite flexural behavior of stiffened ring of cylindrical shell structure. The experimental results are compared with the theoretical and FEM results by commercial program ABAQUS to verify the effective width coefficient. The yield, crack and ultimate loads is calculated using theoretical strains that varies depending on yield state and compared with experiment result and FEM results by ABAQUS solid model.

• Steel and Composite Structures
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• v.19 no.1
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• pp.75-92
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• 2015

In this paper, optimization of cylindrical shells under external pressure to minimize its weight has been studied. Buckling equations are based on standard of ABS underwater vehicles. Dimension and type of circumferential stiffeners, and its distance from each other are assumed as variables of optimization problem. Considering the extent of these variables, genetic algorithms have been used for optimization. To study the effect of hydrostatic pressure on the shell and its fabrication according to the existing standards, geometrical and construction as well as stress and buckling constraints have been used in optimization algorithm and also penalty functions are applied to eliminate weak model. Finally, the best model which has the minimum weight considering the applied pressure has been presented.