• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.353-358
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• 1998

The strain localization is a discontinuous phenomenon that addresses the formation of jumps of the field variables across a singularity surface. It has become widely accepted that the localization may occur as the result of discontinuous bifurcation which corresponds to the loss of ellipticity of the governing differential equations for elasto-plastic continua. In this paper, condition for strain localization in concrete based on bifurcation theory is studied and localization tensor analysis algorithm is employed to determine the directions of localization of deformations in concrete. By applying a plasticity model of concrete into the algorithm, localization analysis is performed concrete under uniaxial tension, pure shear and uniaxial compression.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.867-872
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• 2000

A 1:12 scale 10-story RC building structure was constructed and the experiment was performed. The test results are presented and compared with the results of the analysis conducted with DRAIN-2DX. It is concluded that some local deformations cannot be described reasonably with the wall model using only Plastic Hinge Beam-Column Element(TYPE02) in DRAIN-2DX whereas the strength and stiffness of the whole structure can be predicted with high reliability.

• Journal of Ship and Ocean Technology
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• 제11권3호
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• pp.14-23
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• 2007

Welding processes cause undesirable problems, such as residual stresses and deformations due to the thermal loads imposed by local heating, melting, and cooling processes. This paper presents a computational modeling technique to simulate the Gas Metal Arc Welding (GMAW) process, emphasizing the effect of the melting bead on the residual stress distribution. Both a three-bar analogy and a three-dimensional thermo-mechanical finite element analysis are carried out in order to explain the effect. Element (de)activation, enthalpy, and adjustment of the reference temperature of thermal strain are considered with respect to the effect of the weld filler metal added to the base metal during a thermo-elastic-plastic analysis. Stress distributions obtained by the present study are compared with measured values and available data from other studies. The effect of the melting bead on the residual stress distribution is discussed and demonstrated.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.143-150
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• 2005

In this study, to evaluate the collision behaviors of the navigating vessel and the dolphin protective system protecting the substructures of bridges, the numerical simulation was performed. The analysis model of vessel bow that the plastic deformations are concentrated was composed by shell elements, and the main body of vessel was modeled by beam elements to represent the mass distribution and the change of potential energy. The material model reflecting the confining condition was used for the modeling of the filling soil of dolphin system. The surrounding soil of the dolphin system was modeled as nonlinear springs. As results, it is verified that the dolphin system can adequately dissipate the kinematic energy of the collision vessel. The surrounding soil of the dolphin system is able to resist the collision force of the vessel. And the major energy dissipation mechanism of collision energy is the plastic deformation of the vessel bow and the dolphin system.

• 대한기계학회논문집A
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• 제22권2호
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• pp.444-450
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• 1998

In the present investigation, it is attempted to derive a yield function and associated flow rules of loose metal powders to predict plastic deformation and density change during compaction. The loose metal powders yield by shear stress as well as hydrostatic stress and the yield strength is much smaller in tension than compression. Therefore, a yield function for the powders is expressed as a shifted ellipse toward the negative direction in the hydrostatic stress axis in the space defined by the two stresses. Each of parameters A, B and .delta. used in the yield function is expressed as a function of relative density and it is determined by uniaxial strain and hydrostatic compressions using Cu powder. Flow rules obtained by imposing the normality rule to the yield function are applied to the analyses of unidirectional, bidirectional and hydrostatic compressions, resulting in an excellent agreement with experiments. The yield function is further examined by checking volume changes in plane stain, uniaxial strain and shear deformations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.465-467
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• 2004

Finite element analysis of welding processes, which entail phase evolution, heat transfer and deformation, is considered in this paper. Attention focuses on numerical implementation of the thermo-elastic-plastic constitutive equation proposed by Leblond et al in consideration of the transformation plasticity. Based upon the multiplicative decomposition of deformation gradient, hyperelastic formulation is employed for efficient numerical integration, and the algorithmic consistent moduli for elastic-plastic deformations including transformation plasticity are obtained in the closed form. The convergence behavior of the present implementation is demonstrated via a couple of numerical examples. Several locking phenomena removed by Solid-shell element.

• 한국공간구조학회논문집
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• 제6권2호
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• pp.85-92
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• 2006

본 연구에서는 철근콘크리트 프리캐스트 대형판의 접합부 설계방법 및 해석방법에 대해서 연구를 수행하였다. 접합부의 설계방법은 수평접합부와 수직접합부의 구조적 거동에 대한 안정성 및 일체성을 확보하기 위한 설계법을 제시하였고, 접합부의 해석은 강체스프링 모델에 의한 탄소성해석을 수행 하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.309-312
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• 2003

Quasi-instanteneously performed creep loading is probably one way to seperate the viscous and the plastic creep from the elastic deformation. For mature concrete no differences seem to exist depending on whether the loading is rapidly applied or not. At early age the plastic deformations probably dominate the deformation. A series of test have been done to measure the quasi-instanteneous deformation in concrete specimens according to loading durations and concrete ages. The present study indicates that even very short-term loading contains creep deformation. As concrete is younger and load duration is longer, the proportion of creep deformation in quasi-instanteneous deformation is increased.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.181-188
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• 2000

This paper describes the energy absorption of a square tube under axi compression by using the finite element method. The overall deformations and lo buckling modes of tube was discussed by "plastic hinge concep Force-displacement function was plotted to show various state that depended or time. Also, mean crush load was expressed as a type of section geometry a material property using dimensional analysis. To verify the energy absorption and the effects of dimensions, The standards Wt used as related density and specific energy, mean crushing load and the resL were discussed by the relation between crush load and deformation, the relati between related density and specific energy, the relation between crush load a mean crush load, the relation between mean crush load and specific energy.ergy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1995년도 춘계학술대회논문집
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• pp.90-106
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• 1995

The "O"S' BONDING make metallic and non-metalic crystal structures and form localized superconducting orbitals , which induce electrical conduction , semi-conduction, and superconduction. The orbitals are proced by Ampere's law, Faraday's law , Meissner effect, highcritical temperature of thecopper oxide layers. abnomal trans-membrane signal in cancer cell and plastic deformations bytwins and dislocations, In the case of alloying metals, the most deterimentla cases of electrical conduction are those of solid solution and intermetalic compound . The highest case for the hardness are also those of solid solution and intermetallic compound. It explains the contributions of the "O"S' BONDING for conduction bands and plastic deformation by twins and dislocations.ns and dislocations.