• Title, Summary, Keyword: 유한요소 접촉해석

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3D Finite Element Simulation of Pellet-Cladding Mechanical Interaction (3차원 유한요소를 이용한 핵연료와 피복관 기계적 거동 해석)

  • Seo, Sang Kyu;Lee, Sung Uk;Lee, Eun Ho;Yang, Dong Yol;Kim, Hyo Chan;Yang, Yong Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.5
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    • pp.437-447
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    • 2016
  • In a nuclear power plant, the fuel assembly, which is composed of fuel rods, burns, and the high temperature can generate power. The fuel rod consists of pellets and a cladding that covers the pellets. It is important to understand the pellet-cladding mechanical interaction with regard to nuclear safety. This paper proposes simulation of the PCMI. The gap between the pellets and the cladding, and the contact pressure are very important for conducting thermal analysis. Since the gap conductance is not known, it has to be determined by a suitable method. This paper suggests a solution. In this study, finite element (FE) contact analysis is conducted considering thermal expansion of the pellets. As the contact causes plastic deformation, this aspect is considered in the analysis. A 3D FE module is developed to analyze the PCMI using FORTRAN 90. The plastic deformation due to the contact between the pellets and the cladding is the major physical phenomenon. The simple analytical solution of a cylinder is proposed and compared with the fuel rod performance code results.

Analysis of a Linear Ultrasonic Motor Considering One Point Contact Mechanism (일점 접촉 문제를 고려한 선형 초음파모터 해석)

  • Yi, Kyung-Pyo;Rho, Jong-Seok;Jung, Hyun-Kyo
    • Proceedings of the KIEE Conference
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    • pp.77-79
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    • 2008
  • 본 논문에서는 고리모양 판의 멀티모드를 이용하여 동작하는 선형 초음파모터에 대한 해석방범을 제시하였다. 고정자의 변위는 3D 유한요소법을 이용하여 해석하였으며, 시간에 따른 접촉 면적과 접촉표면의 운동속도의 변화를 반영한 해석적 방법을 이용하여 고정자와 이동자 사이의 접촉을 해석하였다. 해석방법 검증을 위하여 외경 10.00mm, 두께 1.00mm인 선형 초음파모터 모델에 대한 해석결과를 실험결과와 비교하였다.

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Analysis of Debonding between Mixed Finite Elements for Saturated Porous Media (혼합유한요소를 통한 다공질매체의 요소분리해석)

  • Tak, Moonho;Lee, Janggeun;Ban, Hoki;Kang, Jaemo
    • Journal of the Korean Geoenvironmental Society
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    • v.18 no.2
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    • pp.53-58
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    • 2017
  • In this paper, we propose a new method to debond between mixed finite elements for porous media in ABAQUS (2014). ABAQUS just provides debonding algorithm for the u-p model using cohesive elements in standard version. However, this approach has a drawback that it is hard to simulate complex debonding problems like element separation, rigid body motion, and contact between separated elements in standard version. ABAQUS-explicit can resolve these complex problems, but cohesive elements for the u-p model cannot be applied. We introduce a new algorithm for debonding for porous media instead of using cohesive elements. In this method, subroutines VUMAT to apply constitutive models and VDISP to separate elements in ABAQUS are used to simulate debonding problems. In addition, a simple 2-D example is demonstrated in the ABAQUS-explicit solver.

Haptic Interface with Deformable Finite Element Model (유한요소 모델링을 통한 변형체의 햅틱 인터페이스)

  • Jun, Seong-Ki;Choi, Jin-Bok;Cho, Maeng-Hyo
    • Proceedings of the Korean Information Science Society Conference
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    • pp.619-621
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    • 2005
  • 햅틱 장치를 이용한 변형체의 실시간 시뮬레이션은 가상현실을 구축하기 위한 중요한 기술의 하나로서 최근에 크게 각광받고 있다. 본 연구에서는 햅틱 장비와 변형체의 정확한 인터페이스를 구축하기 위하여 변형체의 물리적 특성을 고려한 연속체적 모델인 유한요소법을 통한 선행해석을 수행한다. 변형체와 햅틱 장치의 상호작용 과정에서 발생하는 변형과 반력을 사용자에게 실시간으로 제공하기 위하여 선행해석 결과를 이용한 변형체의 정적 시뮬레이션을 구현한다. 이와 함께 햅틱 장치와 접촉이 이루어지는 부분의 변형을 보다 자연스럽게 표현하기 위하여 적응적 유한요소법인 s-adaptive 방법을 적용하였으며 햅틱 장치와 접촉이 끝난 후의 변형체가 평형 상태로 돌아가는 과정을 모사하기 위하여 Newmark scheme을 통한 동적 시뮬레이션을 구현한다. 또한 최적화 행렬 연산 함수인 BLAS와 LAPACK을 이용하여 행렬 연산을 빠르게 수행하고 효율적인 메모리 사용 추구한다.

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Pressure Analysis of Plantar Musculoskeletal Fascia while Walking using Finite Element Analyses (상세유한요소 모델링을 통한 보행중인 인체족부의 족저압 해석)

  • Jeon, Seong-Mo;Kim, Cheol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.8
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    • pp.913-920
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    • 2012
  • An efficient 3D finite element walking model that considers the detailed shapes of muscles, ligaments, bones, skin, and soles was developed based on a real computed tomography (CT) scan image of a foot, and nonlinear contact analyses were performed to investigate pressure changes. The highest pressure occurs at the rear bottom of the foot when standing and walking. The pressure on the outsole with a curved foot bottom surface is lessened and distributed over a wider area than in the case of a flat outsole. The result shows that a shoe sole shape optimized for diabetes patients can relieve the foot pressure concentration and prevent further worsening of symptoms.

A Solution of Variational Inequalities and A Priori Error Estimations in Contact Problems with Finite Element Method (접촉문제에서의 변분부등식의 유한요소해석과 A Priori 오차계산법)

  • Lee, Choon-Yeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.9
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    • pp.2887-2893
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    • 1996
  • Governing equations infrictional contact problems are introduced using variational inequality formulations which are regularized to overcome the diffculties of non-differentiability of the friction functional. Also finite element approximations and a priori error estimations are derived based on those formulations. Numerical simulations are performed illustrating the theoretical results.

Two Dimensional Elastic Finite Element Analysis for Fretting Contacts (프레팅 접촉에 대한 2차원 유한요소 탄성해석)

  • Jang Song-Koon;Rho Hong-Rae;Cho Sang-Bong
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1648-1651
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    • 2005
  • Fretting contact and fretting fatigue are known to occur in mechanical devices which have fasteners subjected to oscillatory tangential load. Theoretical studies on fretting contact have been focussed on simple geometries, such as cylindrical contact problem. Recently, the contact problem of a flat rounded punch has been solved theoretically. The purpose of this paper is to show that the results of finite element analysis for the fretting contact problem are nearly consistent with the theoretical solutions.

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Application of New Edge-to-Edge Contact Algorithm to Discontinuous Deformation Analysis (불연속 변형해석에서의 새로운 선-선 접촉 해석 적용)

  • Lee Chung-In;Moon Young-Sam;Choi Yong-Keun;Ahn Tae-Young
    • Tunnel and Underground Space
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    • v.15 no.4
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    • pp.305-315
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    • 2005
  • DDA (Discontinuous Deformation Anlaysis) is one of the latest numerical analysis which has merits of both FEM and DEM. In this research a new edge-to-edge contact algorithm was applied on DDA. With adoption of new edge-to-edge contact state definition, sub-algorithm was improved about open-close iteration, contact state judge, contact detecting, and friction forces acting on joints. Newly applied DDA was verified based on two different cases. The DDA results show good agreement with numerically predicted one.

A parametric study of bolt-nut joints by the method of finite element contact analysis (유한 요소 접촉 해석법에 의한 나사 체결부 설계 개선에 관한 연구)

  • 이병채;김영곤
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.3
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    • pp.353-361
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    • 1989
  • A parametric study of load distribution in bolt-nut joints is performed by the method of finite element contact analysis. The contacting surface is assumed unbonded and frictionless. Multi-body contact analysis is performed in elastic region under the assumption of axi-symmetric stress state. Load acting on the first thread from the fastened plate is much greater than that on the other threads in the standard setting. But the load distribution is shown to be improved by making the center of contact force acting on the nut surface move outwards. Such a modification is possible by enlarging the gap between bolt shank and fastened plate or by inserting suitable washers. Shape modification of the standard nut by the making a groove and a step on the nut surface is also suggested, which results in almost uniform load distribution and considerable decrease in the maximum stress of the joint.

Thermoelastic Contact Analysis of Drums Brakes by Finite Element Method (유한요소법에 의한 드럼 브레이크의 열탄성 접촉해석)

  • 구병춘;서정원
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.3
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    • pp.173-180
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    • 2001
  • In the case of axisymmetric thermal analysis of drum brakes, the distribution of frictional heat produced on the interface and temperature difference between mating frictional faces are very interesting problems to computational researchers. In the first part, the influence of the s-cam load angles and elastic modulus of the pad on the contact pressure distribution between pad and drum was checked by a three dimensional model. In the second part heat conduction from the interface to the pad and the drum was modeled by using a thin interface element, so artificial division of the generated frictional heat between pad and drum is not necessary. Temperature difference between mating frictional faces is successfully modeled by using the interface element. The influence of some parameters on the thermal distribution is checked. The analysis was performed by ABAQUS/Standard code.

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