• Title/Summary/Keyword: Continuum model

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연속법에 의한 판구조 고유진동수의 민감도 해석 (Eigenvalue design sensivity analysis of structure using continuum method)

  • 이재환;장강석;신민용
    • 한국해양공학회지
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    • 제11권1호
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    • pp.3-9
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    • 1997
  • In this paper, design sensivity of plate natural frequency is computed for thickness design variables. Once the variational equation is derived from Lagrange quation using the virtual displacement, governing energy bilinear form is obtained and sensivity equation is formulated through the first variation. Natural frequency is obtained using the commercial FEM code and the accuracy of sensivity is verified by finite difference. The accuracy of natural frequency and sensivity improves for the fine mesh model.

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분사압력변화가 분무특성에 미치는 영향에 관한 수치적 고찰 (Numerical Analysis of the Effect of Injection Pressure Variation on Spray Characteristics)

  • 박권하
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1997년도 추계 학술대회논문집
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    • pp.113-119
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    • 1997
  • This paper addresses to the injection pressure effect on the diesel spray. The injection pressure is varied from 10MPa, in general system, upto 200MPa, in high pressured system in order to understand the effect. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. The droplet distributions, vapor fractions and gas flows are analyzed in various injection pressure cases.

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A framework for geometrically non-linear gradient extended crystal plasticity coupled to heat conduction and damage

  • Ekh, Magnus;Bargmann, Swantje
    • Multiscale and Multiphysics Mechanics
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    • 제1권2호
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    • pp.171-188
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    • 2016
  • Gradient enhanced theories of crystal plasticity enjoy great research interest. The focus of this work is on thermodynamically consistent modeling of grain size dependent hardening effects. In this contribution, we develop a model framework for damage coupled to gradient enhanced crystal thermoplasticity. The damage initiation is directly linked to the accumulated plastic slip. The theoretical setting is that of finite strains. Numerical results on single-crystalline metal showing the development of damage conclude the paper.

기포-자유표면 상호작용에 대한 수치적 고찰 (Numerical Simulation of Bubble-Free Surface Interaction)

  • 양찬규;김현주
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 1999년도 춘계 학술대회논문집
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    • pp.48-57
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    • 1999
  • This paper deals with the numerical simulation of the behavior of single bubble rising near the free surface. Volume fraction of fluid (VOF) method with continuum surface force (CSF) model, the well known method for two phase flow simulation is adopted. A bubble of spherical shape positioned beneath the free surface is assumed at the initial stage. The difference according to the fluid properties of surrounding medium is examined. Simulation results are depicted and explained with the time history of bubble shape, velocity field and vorticity distribution.

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연속체 역학을 이용한 사면의 한계상태 해석 (Limit State Analysis of Earthern Slope Using a Continuum Mechanics Approach)

  • 서영교
    • 한국지반공학회논문집
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    • 제16권5호
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    • pp.141-148
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    • 2000
  • 사면 안정 해석은 주로 파괴 활동면의 전단 강도와 발휘되는 전단 강도의 최대비로서 표현되는 파괴활동의 추정을 위해 기존의 고전적인 방법을 사용하거나 이와 유사한 방법등이 사용되어 왔다. 이러한 방법들은 토질에 있어서의 상호 작용력과 그에 따른 전당력 및 사면 활동면의 반복되는 추정등의 가정으로 불확실성을 내포하고 있다. 본 연구에서는 토질전체를 연속체로 규정하고 비선형 유한요소법을 이용한 토질의 실제 응력과 강도를 정확하게 계산하였다. 사면 안정은 점차적 인증력의 증가로서 사면의 붕괴 활동면이 나타나FEo 까지로 해석되었다. 제시된 방법의 세부적인 사항은 예제를 통하여 설명되어 있다.

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Optical phonon and scattering in uniaxial crystals

  • Lee, B.C
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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    • pp.118-118
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    • 2000
  • We investigate Frohlich-like electron--optical-phonon interactionsin uniaxial crytals based on the macroscopic dielectric continuum model. In general, the optical-phonon branches support mixed longitudinal and transverse modes due to the anisotropy. For heterostructures with double interfaces and superlattices, it is known that confined, interface, and half-space optical phonon modes exist in zincblende cystals. In uniaxial structures, additional propagating modes may exist in wurtzite heterosystems due to anisotropic phonon dispersion. This is especially the case when the dielectric properties of the adjacent heterostructure materials do not differ substantially. The dispersion relations and the interaction Hamiltonians for each of these modes are derived.

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Dynamics of Pore Growth in Membranes and Membrane Stability

  • W. Sung;Park, P. J.
    • 한국생물물리학회:학술대회논문집
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    • 한국생물물리학회 1998년도 학술발표회
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    • pp.15-15
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    • 1998
  • Pores can form and grow in biomembranes because of factors such as thermal fluctuation, transmembrane electrical potential, and cellular environment. We propose a new statistical physics model of the pore growth treated as a non-Markovian stochastic process, with a free energy barrier and memory friction from the membrane matrix treated as a quasi-two-dimensional viscoelastic and dielectric fluid continuum.(omitted)

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Morphology of radio relics in galaxy clusters

  • Fernandez, Paola Dominguez
    • 천문학회보
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    • 제46권1호
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    • pp.36.1-36.1
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    • 2021
  • Galaxy clusters host Mpc-scale diffuse radio emission giving us evidence of large-scale magnetic fields in the Universe. It is relevant to understand magnetic field amplification processes occurring at the center and outskirts of galaxy clusters. Each of these processes are believed to give rise to observed radio haloes and radio relics, respectively. In this work, we focus on studying the continuum and polarised emission in radio relics. We use threedimensional magnetohydrodynamical simulations of merger shock waves propagating through a magnetized, turbulent intracluster medium. Our model includes the diffusive shock acceleration (DSA) of cosmic ray electrons, their spatial advection and energy losses at run-time. We discuss the relation between the mock observation features and the underlying morphology of the magnetic field.

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