• Journal of the Korea Institute of Military Science and Technology
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• v.2 no.2
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• pp.148-156
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• 1999

The thermal postbuckling and vibration characteristics of cylindrical composite panel subject to thermal loads are analyzed using finite elements. The von-Karman nonlinear displacement-strain relation based on the layerwise theory is applied to consider large deflections due to thermal loads. Cylindrical arc-length method is used to take into account the snapping phenomena. Thermal snapping and vibration characteristics are investigated for various structural parameters such as thickness ratio, shallowness angle and boundary conditions. The present results show that thermal snapping changes the mode shapes as well as static deformations.

• Composites Research
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• v.15 no.3
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• pp.52-61
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• 2002

For the aerothermoelastic analysis of cylindrical piezolaminated shells, geometrically nonlinear finite elements based on the multi-field layerwise theory hale been developed. Applying a Han Krumhaar's supersonic piston theory, supersonic flutter analyses are performed for the cylindrical piezolaminted shells subject to thermal stresses and deformations. The possibility to increase flutter boundary and reduce thermoelastic deformations of piezolaminated panels is examined using piezoelectric actuations. Results show that active piezoelectric actuations can effectively increase the critical aerodynamic pressure by retarding the coalescence of flutter modes and compensating thermal stresses.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.5
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• pp.88-93
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• 2003

Buckling behavior of stiffened laminated composite cylindrical panel was studied using linear and nonlinear deformation theory. Various buckling load factors are obtained for stiffened laminated composite cylindrical panels with rectangular type longitudinal stiffeners and various longitudinal length to radius ratio, which made from Carbon/Epoxy USN150 prepreg and are simply-supported on four edges under uniaxial compression. Buckling behavior design analyses are carried out by the nonlinear search optimizer, ADS.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1361-1369
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• 2005

Based on a full layerwise displacement shell theory, the nitration and damping characteristics of cylindrical sandwiched panels with viscoelastic layers are investigated. The transverse shear deformation and the normal strain of the cylindrical hybrid panels are fully taken into account for the structural damping modelling. The present finite element model Is formulated by using Hamilton's virtual work principle and the cylindrical curvature of hybrid panels is exactly modeled. Modal loss factors and frequency response functions are analyzed for various structural parameters of cylindrical sandwich panels. Present results show that the full layerwise finite element method can accurately predict the vibration and damping characteristics of the cylindrical hybrid panels with surface damping treatments and constrained layer damping.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.272-281
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• 1999

Cylindrical panels are widely used as aircraft fuselages and rocket etc, and the cutouts for weight reduction or wiring at such structures tend to cause the stress concentration and the local radial displacement so that seriously effect the stability of structures. In this paper, for the cylindrical composite panel with coutout at the center, the buckling and postbuckling behaviour regarding the shape and size of cutout is analyzed by finite element method. Also the lamination mechanism , changing bending stiffness and fiber orientation angle variation are researched to be regarded in studying the laminated composite materials.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.772-778
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• 2005

Based on a full layerwise displacement shell theory, the vibration and damping characteristics of cylindrical sandwiched panels with viscoelastic layers are investigated. The transverse shear deformation and the normal strain of the cylindrical hybrid panels are fully taken into account for the structural damping modelling. The present finite element model is formulated by using Hamilton's virtual work principle and the cylindrical curvature of hybrid panels is exactly modeled. Modal loss factors and frequency response functions are analyzed for various structural parameters of cylindrical sandwich panels. Present results show that the full layerwise finite element method can accurately predict the vibration and damping characteristics of the cylindrical hybrid panels with surface damping treatments and constrained layer damping.

• Proceedings of the KAIS Fall Conference
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• 2001.05a
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• pp.103-107
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• 2001

This study is simulation about buckling behavior under axial compression which is cylindrical panel laminated USN125 and USN150 made by various winding angle. And also this study compare with linear and nonlinear FDEM theory, and FEM theory. To solve the objective function and the design variables, this study use the linear and nonlinear buckling theories or FDEM and nonlinear search optimum design method of ADS for minimum weight design on which stiffened laminated composite cylindrical panel with stiffener that R-type section.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.549-554
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• 2000

In this study, using linear and nonlinear deformation theories and by closed-form analysis and finite difference energy methods, respectively, various buckling load factors are obtained for stiffened laminated composite cylindrical panels with rectangular type longitudinal stiffeners and various longitudinal length to radius ratios, which are made from Carbon/Epoxy USN150 prepreg and are simply-supported on four edges under uniaxial compression, and then for them, buckling behavior design analyses are carried out by the nonlinear search optimizer, ADS

• Composites Research
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• v.14 no.4
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• pp.27-34
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• 2001

The finite element method based on the total Lagrangian description of the motion and the Hellinger-Reissner principle with independent strain is applied to investigate the nonlinear behavior and vibration characteristics for patched reinforced laminated spherical panels. The patched elements are formulated using variable thickness at arbitrary point on the reference plane. The cylindrical arc-length method is adopted to obtain a nonlinear solution. The post-buckled vibration is assumed to be small amplitude. The effect of patch in the spherical shell Panel is investigated on the nonlinear response and the fundamental vibration characteristics. The present results show that the load-carrying capability can be improved by reinforcing patch. The fundamental frequency of patched panel is lower than that of equivalent shell panel. However, the fundamental frequency of patched panel does not decrease greatly due to the increase of nonlinear geometrical stiffness under loading.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.131-134
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• 2002

Supersonic flutter analysis of cylindrical composite panels with structural damping treatments has been performed using the finite element method based on the layerwise shell theory. The natural frequencies and loss factors of cylindrical viscoelastic composites are computed considering the effects of transversely shear deformation. The panel flutter of cylindrical composite panels is analyzed considering structural damping effect. Various damping characteristics for unconstrained layer damping, constrained layer damping, and symmetrically co-cured sandwich laminates are compared with those of an original base panel in view of aeroelastic stabilities.