• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.367-374
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• 2012

A dynamic simulation and test of frame with thin walled closed section beams considering warping conditions have been performed. When a beam is subjected under torsional moment, the cross section will deform an warping as well as twist. For some thin-walled sections warping will be large, and accompanying warping restraint will induce axial and shear stresses and reduce the twist of beam which stiffens the beam in torsion. This paper presents that an warping restraint factor in finite element model effects the behavior of beam deformation and dynamic mode shape. The computer modelling of frame is discussed in linear beam element model and linear thin shell element model, also presents a correlation between computer predicted and actual experimental results for static deflection, natural frequencies and mode shapes of frame.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.136-152
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• 1993

This study is intended to develop an accurate and efficient, analytical thin-walled beam model, and to analyze overall behavior of SWATH ship under repeated overloads. SWATH ship is idealized to a simple thin-walled beam of channel type. An analytical beam model is formulated by the stress component with geometrically(fully) nonlinear thin-walled beam and treated numerically by the Finite Element Method. An efficient cyclic plasticity model is also included, suitable for material nonlinear behavior under complex loading conditions. The local stress distribution can be very exactly represented and the material yielding propagation, easily traced. In addition, the local treatment of the effect of shear deformation improves the representation of deformation and shear stress distribution along the section contour. It is desirable to use the analytical thin-walled beam at initial design stage, and is needed to improve the practical thin-walled beam model advancing the current approach.

• Composites Research
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• v.17 no.5
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• pp.7-14
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• 2004

This paper deals with adaptive fuzzy logic controller design to achieve proper dynamic response of a composite thin-walled beam with a tip mass. In order to check the effectiveness of this controller, three different types of control logic are selected and applied. The adaptive control capabilities provided by a system of piezoactuators bonded or embedded into the structure are also implemented in the system. Results show that the fuzzy logic controller is more effective than the proportional or velocity feedback controller for the vibration control of composite thin-walled beam with a tip mass.

• Journal of the Earthquake Engineering Society of Korea
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• v.16 no.2
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• pp.25-33
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• 2012

To examine the performance of a thin plate damper attached to coupling beam of bearing wall system, 5 specimens were designed with the variable parameters of the thickness and length of a thin steel plate, which was constructed and tested with a lateral load with up to a 5% drift ratio. The result was that the total amount of the energy dissipation of the specimen with the thin plate damper was greater than that of the standard RC specimen, and the plate buckling and plastic deformation could be seen in steel plate. The shorter the length of the damper, the higher was the lateral resistant force, but there was no apparent increase in the energy dissipation. By comparison of the experiments with the elastic buckling analysis, it was shown that the buckling force from the analysis could properly estimate the maximum value of the linear elastic range.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.4
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• pp.99-107
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• 1997

A mixed type finite element method is applied to the nonuniform shear warping beam theory which is very useful for the structural analysis of thin-walled sectional beams considering the shear deformation. As known generally, it is shown that the mixed type finite element method, compared with the displacement type one, can give more balanced accuracy of results in calculating the stresses and displacements of the structure. In this paper, one typical example, the flexural-torsional problem of a discontinuously variable sectional beam under coupled end torsional moments, is selected and analyzed to validate the usefulness of the developed beam element.

• Computational Structural Engineering
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• v.16 no.2
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• pp.71-78
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• 2003

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.111-117
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• 2017

In this paper, a local deformation effect in thin-walled box beams is investigated via a finite element modal analysis. The analysis is carried out for single-cell and multi-cell box beam configurations. The single-cell box beam with and without a neck, which mimics a simple wind-turbine blade, is analyzed first. The results obtained by shell elements are compared to those of one-dimensional(1D) beam elements. It is observed that the wall thickness plays a crucial role in the natural frequencies of the beam. The 1D beam analysis deviates from the shell analysis when the wall thickness is either thin or thick. The shell modes(local deformations) are dominant as it becomes thin, whereas the shear deformation effects are significant as it does thick. The analysis is extended to the single-cell box beam with a neck, in which the shell modes are confined to near the neck. Finally the multi-cell box beam with a taper, which is quite similar to real wind-turbine blade configuration, is considered to investigate the local deformation effect. The results reveal that the 1D beam analysis cannot match with the shell analysis due to the local deformation, especially for the lagwise frequencies. There are approximately 5~7% errors even if the number of segments is increased.

• Composites Research
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• v.19 no.5
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• pp.1-6
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• 2006

In this study, a closed-form analysis has been developed for the transverse shear behavior of thin-walled composite beams with closed cross-sections. The shear flow distributions and cross-section stiffness coefficients are derived analytically by using a mixed beam approach. The theory has been applied to single-celled composite box-beams with elastic couplings. The location of the shear center and the effect of transverse shear deformation on the static behavior of composite beams are investigated in the framework of the analysis. The present results are validated against those of a two-dimensional finite element analysis and a good correlation has been obtained for box-beam cases considered in this study.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2637-2645
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• 2000

We propose a new one-dimensional theory for thin-walled curved box beams having rectangular cross sections, in which torsional, out-of-plane bending, warping and distortional deformations are coupled. The major difference between the present theory and existing theories lies in that the present theory takes into account additional distortion as well as warping. To verify the present theory, a standard finite element based on the present theory is developed and used for numerical analysis. A couple of numerical examples indeed confirm that the consideration of warping and distortional deformations is very important.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1119-1128
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• 1990

A numerical method for analyzing non-isothermal, rigid-viscoplastic deformation problems has been presented. As an application, a stretch forming of sheet metals, including temperature effect, has been analyzed by a three-dimensional finite element method. Bishop`s step-wise decoupled method is adopted to solve thermomechanical coupling between deformation and heat transfer. Using the method, the effect of temperature on strain distribution during stretch forming is investigated. By comparison of the non-isothermal results with isothermal analysis, the importance of including temperature effects in the analysis of metal forming problems is emphasized. The predicted results were in good agreement with the existing experimental measurements at the different punch temperatures and dome heights investigated. It is also found that any increase of the punch temperature appeared to postpone the strain localization process by lowering the peak strain in the critical punch-sheet contact region and by normalizing strain distribution within the specimen.