• Title, Summary, Keyword: Generalized Plane Strain Condition

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Numerical Simulation of Turbulent Flows Under a Plane Rate of Strain Condition in a Rotating $90^{\circ}$ Curved Duct (평면변형율 조건 하의 회전하는 $90^{\circ}$ 곡덕트 내 난류유동의 전산해석)

  • Kwon, Hyung-Joong;An, Jung-Soo;Choi, Young-Don
    • Proceedings of the KSME Conference
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    • pp.485-490
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    • 2000
  • The effect of curvature, rotation, variable cross-section can make very complex flow pattern in turbo-machinery such as Pumps, compressors, turbines, In this study of turbulent flow characteristics rotating $90^{\circ}$ curved duct under a Plane rate of strain condition is computationally analyzed. The objective of this study is to understand the complex turbulent flow phenomena in turbo-machinery passage by analyzing the modeled rotating $90^{\circ}$ curved duct flow. RSM(Reynolds Stress Model) was employed for the turbulence modeling of Reynolds stress in momentum equations proposed by Shin(1995). The three dimensional computational code which adopts RSM for trubulence modeling was newly developed for the generalized curvilinear coordinate.

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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.

Finite Element Analysis of the Non-axisymmetric Extrusion Process (비축대칭 압출 공정의 유한 요소 해석)

  • 신현우
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.27-46
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    • 1992
  • In this study a new simplified three-dimensional numerical method and the associated computer program have been developed to simulate the non-axisymmetric extrusion processes. The two-dimensional rigid-plastic finite element method under the generalized plane-strain condition, is combined with the slab method. To define the die geometry for non-axisymmetric extrusion, area mapping technique was used. Streamlined die surface was used to miniminze the total extrusion pressure. Extrusion of square, hexagonal and "T" section from round billet have been simulated and experimented with a model material. The computed results were in good agreement with the experiments in cross-sectional grid distortion. Computational results will be valuable for designing tool geometries and corresponding processes.

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The Analysis of H-Shape Rolling by the Finite Element Method (유한요소법에 의한 H형강 압연공정의 해석)

  • 신현우;김낙수;박종진
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.5
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    • pp.1095-1105
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    • 1993
  • Shape rolling processes to produce H-section beams are numerically simulated by the simplified three-dimensional finite element method. The 2-dimensional finite element method, used for the generalized plane strain condition, is combined with the slab method. Computer simulation results of the 19-passes in H-section beam rolling in practice include the grid distortions, the cross-sectional area changes, the roll separating forces, and the roll torques. Also, the amount of side spread can be found during the multi-pass rolling simulations. The finite element mesh system is remeshed with I-DEAS whenever the billet distorts severely. This study would contribute to CAD/CAM of shape rolling process through the optimal roll pass schedule.

A Simplified Three-Dimensional Finite Element Analysis of the Non-axisymmetric Extrusion Process (비축대칭 압출 공정의 근사 3차원 유한 요소 해석)

  • Shin, H.W.;Kim, D.W.;Kim, N.
    • Transactions of Materials Processing
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    • v.1 no.1
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    • pp.52-65
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    • 1992
  • In this study a new simplified three-dimensional numerical method and the associated computer program have been developed to simulate the non-axisymmetric extrusion processes. The two-dimensional rigid-plastic finite element method under the generalized plane-strain condition is combined with the slab method. To define the die geometry for a non-axisymmetric extrusion. area mapping technique was used. Streamlined die surface was used to minimize the total extrusion pressure. Extrusion of square, hexagonal and 'T' section from round billet have been simulated and experimented with a model material. The computed results were in good agreement with the experiments in cross-sectional grid distortion. Computational results will be valuable for designing tool geometries and corresponding processes.

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Method of Quasi-Three Dimensional Stability Analysis of the Root Pile System on Slope Reinforcement (사면보강 뿌리말뚝공법의 준3차원적 안정해석기법)

  • Kim, Hong-Taek;Gang, In-Gyu;Park, Sa-Won
    • Geotechnical Engineering
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    • v.13 no.5
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    • pp.101-124
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    • 1997
  • The root pile system is insitu soil reinforcement technique that uses a series of reticulately installed micropiles. In terms of mechanical improvement by means of grouted reinform ming elements, the root pile system is similar to the soil nailing system. The main difference between root piles and soil nailing are due to the fact that the reinforcing bars in root piles are normally grouted under high pressure and that the alignments of the reinforcing members differ. Recently, the root pile system has been broadly used to stabilize slopes and retain excavations. The accurate design of the root pile system is, however, a very difficult tass owing to geometric variety and statical indetermination, and to the difficulty in the soilfiles interaction analysis. As a result, moat of the current design methods have been heavily dependent on the experiences and approximate approach. This paper proposes a quasi-three dimensional method of analysis for the root pile system applied to the stabilization of slopes. The proposed methods of analysis include i) a technique to estimate the change in borehole radium as a function of the grout pressure as well as a function of the time when the grout pressure is applied, ii) a technique to evaluate quasi -three dimensional limit-equilibrium stability for sliding, iii) a technique to predict the stability with respect to plastic deformation of the soil between adjacent root piles, and iv) a quasi -three dimensional finite element technique to compute stresses and dis placements of the root pile structure barred on the generalized plane strain condition and composite unit cell concept talon형 with considerations of the group effect and knot effect. By using the proposed technique to estimate the change in borehole radius as a function of the grout pressure as well as a function of the time, the estimations are made and compar ed with the Kleyner 8l Krizek's experimental test results. Also by using the proposed quasi-three dimensional analytical method, analyses have been performed with the aim of pointing out the effects of various factors on the interaction behaviors of the root pile system.

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