• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.296-303
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• 2000

The purpose of this study is to find inelastic behavior and ductility capacity of reinforced concrete bridge columns under earthquake. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, due to the abrupt change in their stiffness local discontinuous deformation can be taken into account by introducing interface element. Also an analytical model is developed to express the confining effects of lateral tie which depend on the existence or nonexistence and the amounts of transverse confinement, etc. The proposed numerical method for inelastic behavior and ductility capacity of reinforced concrete bridge columns will be verified by comparison with reliable experimental results.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.805-812
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• 2003

The purpose of this study is to evaluate the behavior of a reinforced earth wall by modeling the properties of the interface between soil and reinforced elements as well as the non-linear stress-strain characteristics of soil. The effect of lateral earth pressures induced during construction is also included in the analyses. The interface element used to evaluate the relative movement of the interface between soil/reinforcement and soil/wall- facing has a zero thickness and essentially consists of normal and shear springs. The behavior of soil element is calculated based on the hyperbolic model. The computer program SSCOMPPC which includes the interface element, hyperbolic model and bi-linear model is applied in this study. From the analyses, it is showed that the locus of maximum tension were closed to the hi-linear failure line of theoretical analyses. The lateral displacement of SSCOMPPC is larger than that of the FLAC which adopts the elastic model. This means the analysis which is adopted the hyperbolic model and interface element induced more larger displacement.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.87-88
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• 2002

To analyze complicated phenomena on the fluid hydrodynamic and the elastic deformation between sliding body surfaces, an analysis to the elastohydrodynamic lubrication of sliding contacts has been developed taking into account the thermal and non-Newtonian effects. The computational technique handled the simultaneous solution of the non-Newtonian hydrodynamic effects, elasticity, the load, the viscosity variation, and temperatures rise. The results included the lubricant pressure profile, film thickness, velocity, shear stress, and temperature distribution, and the sliding frictional force on the surface at various slip conditions. These factors showed a great influence on the behavior resulted in the film shape and pressure distribution. Especially, Non-Newtonian effects and temperature rise by the sliding friction force acted as important roles in the lubrication performance.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.815-820
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• 2011

The railway bridge of the domestic still has been used steel base such as sperical bearing and pot bearing widely. However, the bearing of steel series is occured corrosion frequently, reduced durability and raised maintenance cost excessively due to the nature of the material. If the elastomeric bearing which is widely used in highway bridge is applied to the railway bridge, it will be able to compensate this defect a lot. In order to apply to the railway bridge used for highway bridge, is needed the control of the bridge ends deflection, lateral displacement and negative reaction. Therefore, the elastomeric bearing can be applied to the railway bridge enough, if installed negative reaction key for control of the bridge ends deflection, improved shear wedge performance for control of the lateral force, adjust the thickness of the elastomeric pad for the minimize deflection, in addition, can be economic design of sub-structures due to damping effect.

• Structural Engineering and Mechanics
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• v.58 no.3
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• pp.423-442
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• 2016

This study considers a functionally graded (FG) elastic layer resting on homogeneous elastic substrate under axisymmetric static loading. The shear modulus of the FG layer is assumed to vary in an exponential form through the thickness. In solution, the FG layer is approximated into a multilayered medium consisting of thin homogeneous sublayers. Stiffness matrices for a typical homogeneous isotropic elastic layer and a half-space are first obtained by solving the axisymmetric elasticity equations with the aid of Hankel's transform. Global stiffness matrix is, then, assembled by considering the continuity conditions at the interfaces. Numerical results for the displacements and the stresses are obtained and compared with those of the classical elasticity and the finite element solutions. According to the results of the study, the approach employed here is accurate and efficient for elasto-static problems of FGMs.

• Advances in materials Research
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• v.5 no.1
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• pp.35-53
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• 2016

Flexural bending analysis of perfect and imperfect functionally graded materials plates under hygro-thermo-mechanical loading are investigated in this present paper. Due to technical problems during FGM fabrication, porosities and micro-voids can be created inside FGM samples which may lead to the reduction in density and strength of materials. In this investigation, the FGM plates are assumed to have even and uneven distributions of porosities over the plate cross-section. The modified rule of mixture is used to approximate material properties of the FGM plates including the porosity volume fraction. In order the elastic coefficients, thermal coefficient and moisture expansion coefficient of the plate are assumed to be graded in the thickness direction. The elastic foundation is modeled as two-parameter Pasternak foundation. The equilibrium equations are given and a number of examples are solved to illustrate bending response of Metal-Ceramic plates subjected to hygro-thermo-mechanical effects and resting on elastic foundations. The influences played by many parameters are investigated.

• Coupled systems mechanics
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• v.1 no.2
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• pp.115-131
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• 2012

Paper presents an improved solution algorithm based on Finite Element Method to analyse piled raft foundation. Piles are modelled as beam elements with soil springs. Finite element analysis of raft is based on the classical theory of thick plates resting on Winkler foundation that accounts for the transverse shear deformation of the plate. Four node, isoparametric rectangular elements with three degrees of freedom per node are considered in the development of finite element formulation. Independent bilinear shape functions are assumed for displacement and rotational degrees of freedom. Effect of raft thickness, soil modulus and load pattern on the response is considered. Significant improvement in the settlements and moments in the raft is observed.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.99-104
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• 2002

This paper presents an analytical prediction of the fatigue damage of reinforced concrete bridge columns subjected to cyclic load. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuity in deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel and concrete. The proposed numerical method for fatigue damage of reinforced concrete bridge columns subjected to cyclic load is verified by comparison with reliable experimental results.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.3
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• pp.901-909
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• 1996

A model is constructed to evaluate the stress intensity factors(SIFs) for composites with an interlaminar crack subjected to as arbitrary crack surface loading. A mixed boundary value problem is formulated by Fourier integral transform method and a Fredholm integral equation of the second kind is derived. The integral equation is solved numerically and the mode I and II SIFs are evaluated for various shear modulus ratios between each layer, crack length to layer thickness, each term of crack surface polynomial loading and the number of layers. The mode I and II SIFs for the E- glass/epoxy composites as well as the hybrid composites are also evaluated.

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.3
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• pp.403-412
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• 2018

Medium-scale tests were conducted to measure and observe the strength and failure behavior of freshwater ice rubble. A custom box measuring $3.05m{\times}0.94m{\times}0.94m$, with Plexiglas walls was built so that failure mechanisms could be observed. Ice rubble beams of nominal thickness 50 cm were produced by placing randomly sized ice pieces into the box filled with water at its freezing temperature. After the specified consolidation time, ranging between 0.2 and 70.5 h, the ice rubble beam was deformed by pushing a platen vertically downwards though the center of the beam until failure. For consolidation times less than 4 h, the ice beam failed progressively and tended to fail by shearing on macroscopic scale. At times greater than 4 h the beam failed by bending. The change in failure behaviour has been attributed to the degree of bonding between ice blocks.