• Title/Summary/Keyword: Non-dilatant flow

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Non-Newtonian Flow Mechanism for Thixotropic and Dilatant Flow Units of Sodium bis-(2-ethylhexyl)sulfosuccinate-water Micelles (Sodium bis-(2-ethylhexyl)sulfosuccinate-water 미셀의 틱소트로 피와 다일레턴시 유동단위에 대한 비뉴톤 유동메카니즘)

  • Kim, Nam Jeong
    • Journal of the Korean Applied Science and Technology
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    • v.33 no.3
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    • pp.540-548
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    • 2016
  • The non-Newtonian flow curves of sodium bis-(2-ethylhexyl)sulfosuccinate-water lamellar liquid crystals were obtained in various concentrations and temperatures by using a cone-plate rheometer. By applying non-Newtonian flow equation to the flow curves for AOT-water lamellar liquid crystal samples, the rheological parameters were obtained. Particular attention is given to the hysteresis loop detected when the liquid crystal samples are shear under increasing-decreasing shear stress modes which result in thixotropic and dilatant behavior. Sodium bis-(2-ethylhexyl)sulfosuccinate-water lamellar liquid crystals behave as weak gels when they are subjected to shear flow, but when the applied stress surpasses the yield stress, they exhibit non-linear viscoelasticity. Upon decreasing shear rate, the dispersion still preserves much of its structure and consequently its shear stress remains higher than the values measured in the increasing shear rate mode.

3-D Concrete Model Using Non-associated Flow Rule in Dilatant-Softening Region of Multi-axial Stress State (3차원 솔리드요소 및 비상관 소성흐름 법칙을 이용한 콘크리트의 응력해석)

  • Seong, Dae Jeong;Choi, Jung Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.2
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    • pp.193-200
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    • 2008
  • Cohesive and frictional materials such as concrete and soil are pressure dependent. In general, failure criterion for such materials inclined with respect to positive hydrostatic axis in Haigh-Westergaard stress space. Consequently, inelastic volumetric strain always positive with associated flow rule. In this study, to overcome this shortcoming, non-associated flow rule which controls volumetric component of plastic flow is adopted. Numerical analysis based on a constitutive model using nonuniform hardening plasticity with five parameter failure criterion and non-associated flow rule has conducted to predict concrete behavior under multi-axial stress state and verified with experimental result.

Comparative study between Finite Element Method and Limit Equilibrium Method on Slope Stability Analysis (사면안정해석에 있어서의 유한요소법과 한계평형법의 비교)

  • 이동엽;유충식
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.483-490
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    • 2002
  • This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement suggesting that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analysis were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of factor of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow rule are selected.

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Comparative Study Between Finite Element Method and Limit Equilibrium Method on Slope Stability Analysis (사면안정해석에 있어서의 유한요소법과 한계평형법의 비교연구)

  • 이동엽;유충식
    • Journal of the Korean Geotechnical Society
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    • v.19 no.4
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    • pp.65-74
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    • 2003
  • This paper presents the results of a comparative study between FEM and LEM on slope stability analysis. For validation, factors of safety were compared between FEM and LEM. The results from the two methods were in good agreement. This suggests that the FEM with the shear strength reduction method can be effectively used on slope stability analyses. A series of analyses were then performed using the FEM for various constitutive laws, slope angles, flow rules, and the finite element discretizations. Among the findings, the finite element method in conjunction with the shear strength reduction method can provide reasonable results in terms of safety. Also revealed is that the results of FEM can be significantly affected by the way in which the type of constitutive law and flow nile we selected.