• 제목/요약/키워드: Welding Residual Stresses Finite Element Method

검색결과 73건 처리시간 0.022초

PREFLEX BEAM 제작시의 용접부 역학적 특성에 관한 연구 (A Study on the Analysis for Welding Residual Stress of Preflex Beam)

  • 방한서;주성민;안해영
    • 한국해양공학회지
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    • 제17권6호
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    • pp.65-71
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    • 2003
  • Since the preflex beam is fabricated through welding, the pre-compressive stresses that should occur over the concrete pier are diminished by the welding residual stresses. Therefore welding residual stresses must be relieved during the fabrication. Therefore, the analysis and examination of the accurate welding residual stress distribution characteristics are necessary. In this study, accurate distribution of welding residual stress of the preflex beam is analyzed by the finite element method, using 2 dimensional and 3 dimensional elements. Further, the thermo-mechanical behavior of the preflex beam is also studied. After the finite element analysis, real distribution of welding residual stress is measured using the sectioning method, and then is compared with the simulation results. The distribution of welding residual stress by finite analysis agreed well with the experimental results.

Heat Source Modeling and Study on the Effect of Thickness on Residual Stress Distribution in Electron Beam Welding

  • Rajabi, Leila;Ghoreishi, Majid
    • Journal of Welding and Joining
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    • 제35권1호
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    • pp.49-54
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    • 2017
  • In this study, the volumetric heat source in electron beam welding (EBW) is modeled through finite element method taking advantage of ABAQUS software package. Since this welding method is being applied in plates with different thicknesses and also considering that residual stresses reduce the strength of these weldments, the effect of thickness in the distribution and magnitude of residual stresses after welding is studied. Regarding the vast application of Inconel 706 super-alloy in aerospace industries, this material was selected in the current research. In order to validate the finite element model, the obtained results were compared to those of other researchers in this area, and good agreement was observed. The simulation results revealed that increase in the plate thickness leads to increase in the residual stresses. In addition heat treatment in the base metal (before welding) increases the residual stresses significantly.

유한요소법에 의한 PREFLEX BEAM의 용접열분포 특성에 관한 연구 (A Study on the Numerical Analysis of Welding Heat Distribution of Preflex Beam)

  • 방한서;주성민;김하식
    • 한국해양공학회지
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    • 제18권2호
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    • pp.52-57
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    • 2004
  • Preflex beam is a method of construction designed to hold the pre-compressive stresses over the concrete pier by the preflexion load. During the fabrication of the girder, welding causes residual stresses. The welding residual stresses must be relieved in order to generate the accurate compressive pre-stresses. In this study, to determine the thermal distribution characteristics on the girder by welding, both three-dimensional finite element analysis and two-dimensional finite element analysis, in a quasi-steady state, is carried out. After comparing each result between the three-dimensional analysis and the two-dimensional analysis, finite element analysis is carried out against the actual girder, and the welding thermal distribution characteristic over the preflex beam is analyzed. It is possible to provide the input data for the analysis of the welding residual stresses.

유한요소법을 사용한 원전 노즐 용접잔류응력의 변수해석 (Parametric study for Welding Residual Stresses in Nozzle of Nuclear Power Plants using Finite Element Method)

  • 김완재;이경수;김태룡;송태광
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.104-109
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    • 2008
  • Distribution of welding residual stresses are mainly characterized by degrees and frequencies of thermal loads applied to materials. However, other effects as component size and clamping condition can also affect stress distributions to a certain extent thus careful manipulation of these parameters based on clear understanding of how they affect residual stresses distributions and why can be additional measure to mitigate residual stresses. This paper discusses aforementioned issues for the case of safety and relief nozzle in nuclear power plant through finite element analysis.

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유한요소법을 이용한 박판 맞대기 용접부 잔류응력 및 균열 해석 (Welding Residual Stress Determination and Crack Analysis in Butt-Welded Thin-Walled Plate by Finite-Element Method)

  • 심광보;배홍열;전준영;송태광;김윤재
    • 대한기계학회논문집A
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    • 제34권5호
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    • pp.589-596
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    • 2010
  • 본 논문은 박판 맞대기 용접부 잔류응력을 3 차원 유한 요소법을 이용해서 모사하였다. 경계조건이 잔류응력에 미치는 영향을 연구하기 위해 다양한 경계조건이 고려되었으며, 예측된 용접 잔류응력은 기존 문헌의 내용과 비교 검증하였으며, 본 연구의 결과는 박판 용접부 균열에 발생하는 잔류응력의 영향을 해석하는데 사용될 것이다.

압축잔류응력에 의하여 선단부가 닫힌 균열의 개구거동에 대한 유한요소법에 의한 해석방법의 제안 (A Proposal of an Analytical Method for Estimating the Opening Behaviour of Tip-Closed Crack in Compressive Residual Stress by Finite Element Method)

  • 김응준;박응준;유승현
    • Journal of Welding and Joining
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    • 제21권6호
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    • pp.71-76
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    • 2003
  • For the purpose of clarifying the influence of welding residual stress to the fatigue crack propagations behaviour, an analytical investigation based on finite element method is performed to examine the opening behaviour of tip-closed crack in the compressive residual stress. A finite element model comprised of contact elements for the crack plane and plane stress elements for the base material is used to evaluate crack opening stress of the crack existing in the residual stress field. Also an analytical method based on the superposition principle to estimate the length of opened part of tip closed crack and the stress distribution adjacent to the crack during uploading is applied to the finite element model. The software for the analysis is ABAQUS, which is a general purpose finite element package. The results show that stresses distributed on the crack surfaces are reduced and approached to zero as the applied stresses are increased up to crack tip opening stress and no mechanical discontinuity is found at the boundary of contact elements and plane stress elements. It is verified that the opening behavior of the fatigue crack in the residual stress can be predicted by finite element method with the proposed analytical method.

Distribution of Welding Residual Stresses in Laser Welds with the Nail-head shape

  • Kim, Y.P.;Joo, S.M.;Bang, H.S.
    • International Journal of Korean Welding Society
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    • 제3권1호
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    • pp.17-22
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    • 2003
  • During the laser welding, weldments are suddenly heated and cooled by laser beam of high density energy. This phenomenon gives an occasion to complex welding residual stresses, which have a great influence on structural instability, in laser welds. However, relevant researches on this field are not sufficient until now and residual stress measurements have experimental and practical limitations. From these reasons, a numerical simulation may be attractive in order to solve the residual stress problem. For clarifying the distribution of heat and welding residual stresses in laser welds with the nail-head shape, authors conduct the finite element analysis (two-dimensional unstationary heat conduction & thermal elastic and plastic analysis). From the results, we can confirm the stress concentration occurs at the place of melting line shape changed in laser welds with the nail-head shape.

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기계적 응력이완 방법에 의한 원전기기 용접부의 잔류응력 재분포 (Residual Stress Redistribution on Welds of Nuclear Component by Mechanical Stress Relieving Methods)

  • 이세환;김종성;진태은
    • Journal of Welding and Joining
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    • 제22권2호
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    • pp.51-58
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    • 2004
  • Residual stresses, which can be produced during the welding process, play an important role in an industrial field. Welding residual stresses are exerting negative effect on the fatigue behavior and integrity of structure. In this study, as a result of the thermal elasto-plastic finite element analysis for the welds of a nuclear component, the residual stress distributions are estimated for as-welded condition. Also, finite element techniques are developed to simulate the relaxation of the residual stresses according to the various mechanical stress relieving(MSR) loads such as hydrostatic pressure loading, tensile pipe-end loading, and mechanical stress improvement process(MSIP) loading. Finally, the results of residual stress redistributions for various loading conditions are compared and reviewed qualitatively and quantitatively to find an optimum loading condition.

PREFLEX BEAM 제작시의 용접부 역학적 특성에 관한 연구 (The Study on the Analysis for Welding Residual Stress of Preflex Beam)

  • 방한서;주성민;김규훈;이창우;이형훈
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2002년도 추계학술대회 논문집
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    • pp.323-328
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    • 2002
  • Since the pre flex beam is fabricated by welding, the precompressive stresses that should occur over the concrete pier are diminished by the welding residual stresses. Therefore the welding residual stresses must be relieved during the fabrication. So the analysis and examination of the accurate welding residual stress distribution characteristic are necessary. On this study, accurate distribution of welding residual stress of preflex beam is analyzed by finite element method.

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유한요소법을 이용한 용접 잔류응력과 열처리 해석 (Analysis of Welding Residual Stresses and Heat Treatment used by Finete Element Method)

  • 이봉열;조종래;문영훈
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.334-339
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    • 2003
  • The welding residual stress has on important effect on welding deformation, fatigue fracture, buckling strength, brittle fracture, etc. For the purpose of relaxation of welding residual stress, post welding heat treatment is widely used. In this paper, residual stresses were calculated by two dimensional thermal elasto-plastic analysis using finite element method. Heat transfer analysis are performed by transient analysis. Also structure analysis are carried out by of thermal-mechanical coupled analysis. Numerical analysis are used by ANSYS 5.7.

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