• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.43-47
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• 2003

This paper presents the optimum design of cylindrical shell under external pressure loading. Two kinds of material, AI7075-T6, Ti-6AI-4V, are considered. For each material, the design variable is a thickness of the unstiffened parallel middle body shell, and the state variable, constraint, is hoop stress and the object function is total weight of the cylindrical shell. Optimization is performed by conventional FE Program, ANSYS. In addition, buckling analysis is performed for the middle body of the cylindrical shell. Finally, we calculates the payload of the cylindrical shell to keep neutral buoyancy with optimized thickness in deep-sea applications.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.41-47
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• 2004

Plate has cutout inner bottom and girder and Door etc. in hull construction absence is used much, and this is strength in case must be situated, but establish in region that high stress interacts sometimes fatally in region that there is no big problem usually by purpose of weight reduction, a person and freight movement, piping etc.. Because cutout‘s existence is positioning in this place, and, elastic bucking strength by load causes large effect in ultimate strength. Therefore, perforated plate elastic bucking strength and ultimate strength is one of important design criteria to decide structural elements size at early structure design step of a ship. Therefore, we need reasonable & reliable design formula for elastic bucking strength of the perforated plate. The author computed numerically ultimate strength change about several aspect ratios, cutout dimension, and plate thickness by using ANSYS Finite element analysis code based on finite element method in this paper.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.121-125
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• 2004

Recently, High Tensile Steel is adapt to thin plate on the steel structure and marine structure is used widely, It is possible for buckling happens great. Specially, Initial deflection of ship structure happens in place absence necessarily by heat processing of welding or cutting etc. This Initial Deflection is exerted negative impact when thin plate absence complicated nonlinear behaviour accompanied secondary budding. As a result, must idealize initial deflection that occurrence is possible to endow stability and accuracy in the hull structure or marine structure and reflect in early structure design considering secondary buckling. Longi direction of compressive load interacts and analyzed finite element series analysis that apply various kinds initial deflection shape measured actually on occasion that is arranged simply supported condition in this research. Applied ANSYS (elasto-plasticity large deformation finite element method) to be mediocrity finite element program for analysis method and analysis control used in Newton-Raphson method & Arc-length method.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.129-135
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• 2004

Plate has cutout inner bottom and girder and floor etc in hull construction absence is used much, and this is strength in case must be situated, but establish in region that high stress interacts sometimes fatally in region that there is no big problem usually by purpose of weight reduction, a person and change of freight, piping etc. Because cutout's existence gnaws in this place, and, elastic budding strength by load rouses large effect in ultimate strength. Therefore, perforated plate elastic budding strength and ultimate strength is one of important design criteria which must examine when decide structural elements size at early structure design step if ship. Therefore, and, reasonable elastic budding strength about perforated plate need design ultimate strength. Calculated ultimate strength change several aspect ratioes and cutout's dimension, and thickness in this investigation. Used program applied ANSYS F.E.M code based on finite element method

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.458-462
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• 2005

This paper deal with the optimal lamination condition of cylindrical shell applied new composite URN300 for a study of composite empirical formula. Finite element analyses for isotropic materials considered element numbers and boundary conditions are compared with existing empirical formulas to apply FE analysis for composite. And composite tensile test is done to know the composite material applied FE analysis for composite. The results of FE analyses for isotropic materials have indicated that Optimal element number and boundary condition were 1600 and both simple support. These conditions were applied in composite FE analyses. Ply orientations and lamination patterns in FE analyses for composite were considered. Ply orientations are $0^{\circ},\;15^{\circ},\;30^{\circ},\;45^{\circ},\;60^{\circ},\;75^{\circ},\;and\;90^{\circ}$. Lamination patterns are $[\pm\theta/0/90]_{14s]$ and $[\pm\theta_{14}/0_{14}/90_{14}]_s$ in FE analysis. Lamination pattern $[\pm\theta_{14}/0_{14}/90_{14}]_s$ is the equivalent model of $[\pm\theta/0/90]_{14s}$. At the result of this study, the FE analyses for composite have indicated that the optimized ply orientation $75^{\circ}$ is and real model must use in FE analysis for accurate results.