• Title, Summary, Keyword: 일반 평면변형률조건

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Behaviour of Foundation Ground with Marine Clay in Anisotropy (이방성을 갖는 해성점토 기초지반의 거동해석)

  • Kim, Myeon-Su;Lee, Kang-Il;Kim, Chan-Ki;Yun, Jung-Mann;Baek, Won-Jin
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.1
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    • pp.11-21
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    • 2015
  • This study aims at investigating of the behavioral characteristics of foundation ground subjected to a strip load in anisotropy. Using marine clays sampled at Shihwa area, a series of laboratory tests including triaxial compressive test, plane strain compressive and expansion tests that allows horizontal deformation only and zero strain (${\varepsilon}_2$) in the direction of intermediate stress (${\sigma}_2$) are conducted. In addition, a numerical analysis using parameters obtained from the tests is carried out. In the numerical analysis, Cam-clay model that simulates the behavior of natural deposited clay properly is adopted. The analysis results show that the vertical displacements of the plane strain compressive tests are relatively larger than those of triaxial compressive tests by 18-25%. Likewise, the horizontal displacements is 13-19% larger.

Viscoplastic Solution of Thick Walled Cylinder Considering Axial Constraint (축방향 경계 조건을 고려한 두꺼운 실린더의 점소성 응력해)

  • Yoon, Sam-Son;Lee, Soon-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.9
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    • pp.1555-1561
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    • 2003
  • Finite element analysis using modern constitutive equation is one of the most general tools to simulate the deformation behavior and to predict the life of the structure. Constitutive equation becomes complicated so as to predict the material behavior more accurately than the classical models. Because of the complexity of constitutive model, numerical treatment becomes so difficult that the calculation should be verified carefully. One-element tests, simple tension or simple shear, are usually used to verify the accuracy of finite element analysis using complicated constitutive model. Since this test is mainly focused on the time integration scheme, it is also necessary to verify the equilibrium iteration using material stiffness matrix and to compare FE results with solution of structures. In this investigation, viscoplastic solution of thick walled cylinder was derived considering axial constraints and was compared with the finite element analysis. All the numerical solutions showed a good coincidence with FE results. This numerical solution can be used as a verification tool for newly developed FE code with complicated constitutive model.

Stress-Strain Characteristics of Weathered Granite Soil in Plane Strain Test (평면변형시험을 이용한 화강풍화토의 응력-변형률 특성)

  • Kim, You-Seong;Lee, Jin-Kwang;Kim, Jae-Hong
    • Journal of the Korean Geotechnical Society
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    • v.30 no.5
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    • pp.37-46
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    • 2014
  • Geotechnical structures have been analyzed and constructed in various geometry conditions to maintain their stability in accordance with the characteristics of construction design. Shear strengths are generally obtained from triaxial test to apply to design analysis. Geotechnical structures under strip loading, such as earth dam, embankment, and retaining wall, have the strain in a direction, and plane strain condition. Thus, an approximate shear strengths should be applied for stability analysis suitable to ground condition. When applying shear strengths obtained from triaxial tests for slope stability analysis, the evaluation of it may underestimate the factor of safety because the implementation is not suitable for geometry condition. The paper compares shear strengths obtained from triaxial test and plane strain test based on various relative densities using weathered granite soils. Additionally, yield stress is determined by maximum axial strain 15% in triaxial test because of continuous kinematic hardening, but plane strain test can determine a failure point in critical state to evaluate the shear strengths of soils at the second plastic hardening step. This study proposes to perform an appropriate test for many geotechnical problems with plane strain condition.

The Free Edge Stress Singularity At An Interface of Bilinear Material Structure (탄성 선형 경화 재료로 구성된 복합 구조물의 자유 경계면에서 나타나는 응력특이도)

  • 정철섭
    • Computational Structural Engineering
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    • v.10 no.3
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    • pp.185-193
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    • 1997
  • The order of the stress singularity that occurs at the termination of an interface between materials exhibiting bilinear stress-strain response under plane strain conditions has been calculated, The governing equation of elasticity together with traction-free boundary condition and interface continuity condition defines a two-point boundary value problem. The stress components near the free edge are assumed to be proportional to r/sup s-1/, with solutions existing only for certain values of s. Finding these values entails the solution of an eigenvalue problem. Because it has been impossible to integrate the differential equations analytically, the integration has been performed numerically with a shooting method coupled with a Newton improvement scheme.

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Train-Structure Dynamic Interaction Analysis of The Bridge Transition Considering Track Irregularity (궤도틀림을 고려한 교대접속부의 열차상호동적거동해석)

  • Choi, Chan-Yong;Kim, Hun-Ki;Chung, Keun-Young;Yang, Sang-Beom
    • Journal of the Korean Geotechnical Society
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    • v.31 no.9
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    • pp.29-38
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    • 2015
  • In this study, track dynamic interaction characteristics caused by the vehicle running through transitional section such as bridge abutments were studied using the finite element analysis program. The geometric condition of track was generated by trigonometric function and allowable maximum track irregularity is determined by KORAIL track maintenance criteria. The sub-infrastructure under rail fastener system was modelled by 3D solid elements. To reduce computational cost only half track line is numerically considered and the roller boundary condition was applied to each side of model. In this study, the vehicle-track dynamic interaction analysis was carried out for standard Korean transition section of concrete track and the dynamic behaviors were investigated. The dynamic characteristics considered are wheel load variation, vertical acceleration at body, and maximum Mises stress at each part of transitional section.