• 제목/요약/키워드: rheology

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Rheology in Two Dimensions

  • Fuller, Gerald G.
    • 한국유변학회:학술대회논문집
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    • 한국유변학회 2001년도 춘계 학술발표회 논문집
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    • pp.3-3
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    • 2001
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레오로지 소재의 고상입자 변형거동 해석 (Solid Particle Behavior Analysis in Rheology Material by Fortran 90)

  • 권기영;강충길
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2008년도 추계학술대회 논문집
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    • pp.234-237
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    • 2008
  • It was reported that the semi-solid forming process has many advantages over the conventional forming process, such as a long die life, good mechanical properties and energy savings. It is very important, however, to control liquid segregation to gain mechanical property improvement of materials. During forming process, Rheology material has complex characteristics, thixotropic behavior. Also, difference of velocity between solid and liquid in the semi-solid state material makes a liquid segregation and specific stress variation. Therefore, it is difficult for a numerical simulation of the rheology Process to be Performed. General Plastic or fluid dynamic analysis is not suitable for the behavior of rheology material. The behavior and stress of solid particle in the rheology material during forging process is affected by viscosity, temperature and solid fraction. In this study, compression experiments of aluminum alloy were performed under each other tool shape. In addition, the dynamics behavior compare with Okano equation to Power law model which is viscosity equation.

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Hydrodynamic interaction between two cylinders in planar shear flow of viscoelastic fluid

  • Jung, Hyun-Wook;Daejin Won;Kim, Chongyoup
    • Korea-Australia Rheology Journal
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    • 제14권4호
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    • pp.203-207
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    • 2002
  • Particle-particle interaction is of great importance in the study of suspension rheology. In this research we have investigated the hydrodynamic interaction between two identical cylinders in viscoelastic fluids numerically as a model problem for the study of viscoelastic suspension. We confine two neutrally buoyant cylinders between two parallel plates and impose a shear flow. We determine the migration velocity of two cylinders. The result shows that cylinders move toward or away from each other depending upon the initial distance between them and that there is an equilibrium distance between two cylinders in viscoelastic fluids regardless of the initial distance. In the case of Newtonian fluid, there is no relative movement as expected. The results partly explain the chaining phenomena of spherical particles in shear flows of viscoelastic fluids.

Structure-property relationship of melt intercalated maleated polyethylene nanocomposites

  • Reddy, M.M.;Gupta, Rahul K.;Bhattacharya, S.N.;Parthasarathy, R.
    • Korea-Australia Rheology Journal
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    • 제19권3호
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    • pp.133-139
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    • 2007
  • Low density polyethylene nanocomposites were prepared by melt intercalating maleic anhydride grafted polyethylene and montmorillonite clay. It has been found that maleic anhydride has promoted strong interactions between polyethylene and montmorillonite, leading to the homogeneous dispersion of clay layers. Rheological experiments revealed that prepared nanocomposites exhibited shear thinning behaviour. Polyethylene nanocomposites exhibited an increase in steady shear viscosities compared to virgin polyethylene owing to strong polymer clay interactions. The tensile strength of nanocomposites was improved but elongation at break decreased considerably. Also, barrier properties improved significantly with montmorillonite content.

콘크리트 비빔 후 경과 시간에 따른 레올로지 정수와 슬럼프 플로의 상관 관계 분석 (Correlation Between Rheology Parameters and Slump Flow Based on Elapsed Time After Concrete Mixing)

  • 이유정;김영기;한동엽
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2022년도 봄 학술논문 발표대회
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    • pp.53-54
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    • 2022
  • This study is a basic study to establish the relationship between the conventional fluidity evaluation data of concrete and the rheology parameters. the slump flow and rheology parameters were measured according to the elapsed time after the concrete was mixed. The correlation between the slump flow and the rheology constant was analyzed and the effect of the elapsed time after concrete beating on the correlation between the two data was analyzed.

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중유동 콘크리트의 재료분리 경계 판단을 위한 레올로지 정수 범위 분석 (Analysis of Rheological Parameters for Determining Segregation of Mid-Range Workability Concrete)

  • 이유정;김영기;한동엽
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 봄 학술논문 발표대회
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    • pp.142-143
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    • 2021
  • The purpose of this study is to analyze the extent of the rheology parameters at the segregation boundary of mid-range workability concrete. In addition, it was intended to present the extent of the rheology parameters of the normal strength concrete with segregation resistance using the determination of segregation occurrence of concrete and the use of the rheology parameters. However, it was confirmed that segregation occurs even if the measured rheology parameters is in the range of the suggested rheology parameters. Therefore, it is determined that the conditions under which segregation occurs will provide fundamental data that can be rheological defined. Additional studies are also needed on the relationship between rheological parameters and segregation.

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