• Steel and Composite Structures
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• v.38 no.2
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• pp.189-211
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• 2021

An analytical solution is presented to analyze the thermoelastoplastic response of a rotating thick-walled cylindrical pressure vessel made of functionally graded material (FGM). The analysis is based on Tresca's yield condition, its associated flow rule and linear strain hardening material behaviour. The uncoupled theory of thermoelasticity is used, and the plane strain condition is assumed. The material properties except for Poisson's ratio, are assumed to vary nonlinearly in the radial direction. Elastic, partially plastic, fully plastic, and residual stress states are investigated. The heat conduction equation for the one-dimensional problem in cylindrical coordinates is used to obtain temperature distribution in the vessel. It is assumed that the inner surface is exposed to an airstream and that the outer surface is exposed to a uniform heat flux. Tresca's yield criterion and its associated flow rule are used to formulate six different plastic regions for a linearly hardening condition. All these stages are studied in detail. It is shown that the thermoelastoplastic stress response of a rotating FGM pressure vessel is affected significantly by the nonhomogeneity of the material and temperature gradient. The results are validated with those of other researchers for appropriate values of the system parameters and excellent agreement is observed.

• Journal of Ocean Engineering and Technology
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• v.19 no.1 s.62
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• pp.95-99
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• 2005

This paper presents the optimum design of cylindrical shell under external pressure loading. Two kinds of material, Al7075-T6, Ti-6Al-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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.156-159
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• 2003

The analytic solution of displacements of thin cylindrical pressure vessel made by carbon fiber T700/Epoxy was obtained using equilibrium equations of orthogonal curvilinear coordinate system. Equilibrium equations with the assumed displacement field were derived from a reasonable description of the behavior of thin elastic shells using principle of virtual work. Some analyses of the theoretical solution are presented and compared with the results of hydraulic tests of the pressure vessel.

• 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 for Nondestructive Testing
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• v.4 no.1
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• pp.5-10
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• 1984

One of the cylindrical reactor vessels in petrochemical plants was examined by acoustic emission method. The vessel was quiet in view of A.E. activity throughout the pressure range $12-44kg.f/cm^{2}.G$. Above the pressure of $44kg.f/cm^2$, some events were appeared lower than 30 counts. In order to verify the events, other Nondestructive testing methods were performed and a surface crack, 10mm in length and 0.8mm in depth, was found on the outside surface of circumferential weld.

• Steel and Composite Structures
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• v.27 no.4
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• pp.525-536
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• 2018

This paper focuses on the application of the first-order shear deformation theory (FSDT) to thermo-elastic static problems of functionally graded carbon nanotubes reinforced composite (FG-CNTRC) cylindrical pressure vessels. A symmetric displacement field is considered as unknown function along the longitudinal direction, whereas a linear distribution is assumed along the thickness direction. The cylindrical pressure vessels are subjected to an inner and outer pressure under a temperature increase. Different patterns of reinforcement are applied as distribution of CNTs. The effective material properties of FG-CNTRC cylindrical pressure vessels are measured based on the rule of mixture, whereas the governing equations of the problem are here derived through the principle of virtual works. A large parametric investigation studies the effect of some significant parameters, such as the pattern and volume fraction of CNTs, on the longitudinal distribution of deformation, strain and stress components, as useful tool for practical engineering applications.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.3
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• pp.228-234
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• 2004

It was discussed about explosion danger of hydrogen gas experimentally that could be happen during the handling and using. Hydrogen concentration was varied from 10 to 60 vol% for get the explosion characteristics of hydrogen and 5 kinds of cylindrical vessel were used to find the explosion characteristics of hydrogen according to the vessel volume. Initial pressure of hydrogen-air mixture was varied from 0.6 to 2 kg/cm2. Based on the experiment, explosion pressure was most high near the 30vol% of hydrogen and explosion pressure was increased slightly according to the increase of vessel volume but explosion pressure rise rate was decreased. Explosion pressure was increased linearly proportional to the initial pressure of gas mixture.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.545-550
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• 2004

KSTAR cryostat is a 8.8 m diameter vacuum vessel that provides the necessary thermal barrier between the ambient temperature test cell and the supercritical helium cooled superconducting magnet providing the base pressure of 1 ${\times}$ $10^{-3}Pa$. The cryostat is a single walled vessel consisting of central cylindrical section and two end closures, a flat base structure with external reinforcements and a dome-shaped lid structure. The base structure has 8 equally spaced support legs anchored on the concrete base. The cryostat vessel design was executed to satisfy the performance and operation requirements. The major loads considered in the structural analysis were vacuum pressure, dead weight, electromagnetic load driven by plasma disruption, and seismic load. Based on the fabrication and inspection procedures for the vessel, cryostat vessel was fabricated and inspected. It was confirmed that the inspection results were acceptable.

• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.319-328
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• 2006

A simple approximation method for the stress intensity factor at the tip of the axial semielliptical cracks on the cylindrical vessel is developed. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. For these, 3-D finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The approximation solutions are within $\pm2.5%$ of the those of finite element analysis using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the approximation method provides sufficiently accurate stress intensity factor values for the axial semi-elliptical flaws on the surface of the reactor pressure vessel.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.2
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• pp.36-43
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• 2003

The analytic solution of radial displacements of thin cylindrical pressure vessel with carbon fiber T700/Epoxy orthotropic composites was obtained using equilibrium equations of the orthogonal curvilinear coordinate system. The governing equations with the simplified strain versus displacement relation of 3-dimensional curvilinear coordinate system were derived from the variational principle and the virtual work principle. Some theoretical analyses were presented and compared with the results of hydraulic tests for the pressure vessels with some various thicknesses. The results of the theoretical analysis and the hydraulic test were reasonably matched.