• 제목/요약/키워드: residual stress distribution

검색결과 469건 처리시간 0.024초

외력을 고려한 양면 필릿용접이음부 루트갭의 영향에 관한 연구 (A Study on the Effect of Root Gap of Double Fillet Welded Joint Considering External Forces)

  • 방한서;김성환
    • 대한용접접합학회:학술대회논문집
    • /
    • 대한용접접합학회 1997년도 특별강연 및 춘계학술발표 개요집
    • /
    • pp.107-111
    • /
    • 1997
  • In this paper distribution of welding residual stress on the double fillet welded joint which exits and not exits root gap, i.e. full penetration and partial penetration is investigated by two dimensional cunduct and thermal elasto-plastic analysis. And stress distribution on notch-tip of the structure where welding residual stress regarded as initial stress and then external load is added is also investigated.

  • PDF

Estimation of residual stress in welding of dissimilar metals at nuclear power plants using cascaded support vector regression

  • Koo, Young Do;Yoo, Kwae Hwan;Na, Man Gyun
    • Nuclear Engineering and Technology
    • /
    • 제49권4호
    • /
    • pp.817-824
    • /
    • 2017
  • Residual stress is a critical element in determining the integrity of parts and the lifetime of welded structures. It is necessary to estimate the residual stress of a welding zone because residual stress is a major reason for the generation of primary water stress corrosion cracking in nuclear power plants. That is, it is necessary to estimate the distribution of the residual stress in welding of dissimilar metals under manifold welding conditions. In this study, a cascaded support vector regression (CSVR) model was presented to estimate the residual stress of a welding zone. The CSVR model was serially and consecutively structured in terms of SVR modules. Using numerical data obtained from finite element analysis by a subtractive clustering method, learning data that explained the characteristic behavior of the residual stress of a welding zone were selected to optimize the proposed model. The results suggest that the CSVR model yielded a better estimation performance when compared with a classic SVR model.

유리 압축 실험에서의 복굴절 분포 예측 (Prediction of birefringence distribution in cylindrical glass compression test)

  • 이주현;나진욱;임성한;오수익
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2004년도 춘계학술대회 논문집
    • /
    • pp.95-100
    • /
    • 2004
  • An analysis using FEM simulation was conducted to predict residual stresses and birefringence in simple compressed cylindrical glass as a preliminary part of the optimum design determination of optical lenses. The FEM simulation with the Maxwell viscoelastic constitutive model was used to predict thermal induced residual stresses and birefringence during the compression test considering stress relaxation. Also the linear photoelastic theory was introduced to calculate birefringence from the residual stress state. The simulation results were in good agreement with deformation and birefringence distribution in the existing experimental result.

  • PDF

X선 회절법을 이용한 $p^+$ 실리콘 내 잔류응력의 깊이 방향 분포 추정 (Determination of the Residual Stress Distribution along the Depth of Silicon by XRD $p^+$ Method)

  • 정옥찬;양의혁;양상식
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
    • /
    • pp.593-595
    • /
    • 1995
  • X-Ray Diffraction method that gives direct information about the deformation of crystal lattice is used for the determination of profiles of the residual stress along the depth of heavily boron doped silicon. The residual stress distribution is obtained by XRD method as measuring the deformation of the front surface of the $p^+$ silicon layer fabricated through different etch time. It is determined that the compressive residual stress exists in the most region except the font surface.

  • PDF

유리 압축 실험에서의 복굴절 분포 예측 (Prediction of Birefringence Distribution in Cylindrical Glass Compression Test)

  • 이주현;나진욱;임성한;오수익
    • 소성∙가공
    • /
    • 제13권6호
    • /
    • pp.509-514
    • /
    • 2004
  • An analysis using FEM simulation was conducted to predict residual stresses and birefringence in simple compressed cylindrical glass as a preliminary part of the optimum design determination of optical lenses. The FEM simulation with the Maxwell viscoelastic constitutive model was used to predict thermal induced residual stresses and birefringence during the compression test considering stress relaxation. Also the linear photoelastic theory was introduced to calculate birefringence from the residual stress state. The error of simulation results between experimental results in the birefringence value at the center of glass specimen is $4.2\%$, and the error in the maximum radius of deformed glass specimen is $1.2\%$. The simulation results were in good agreement with deformation and birefringence distribution in the existing experimental result.

용접잔류응력장에서의 피로균열 성장거동에 관한 연구(I) (A Study on the Fatigue Crack Growth Behavior in Welding Residual Stress Field(I))

  • 최용식;김영진;우흥식
    • 한국안전학회지
    • /
    • 제5권1호
    • /
    • pp.19-29
    • /
    • 1990
  • The objective of this paper is to investigate the effect of residual stresses on the $\Delta$K$\sub$th/ and fatigue crack growth behavior of butt weldments. For this purpose, transverse butt sutmerged arc welding was performed on SM50A steel plate and CT(compact tension) specimens which loading direction is perpendicular to weld bead were selected. Welding residual stresses distribution on the specimen was determined by hole drilling method. The case of crack located parallel to weld bead, the states of as weld and PWHT, $\Delta$K$\sub$th/ of specimens(HAZ, weld zone) was higher than that of the base metal probably because of the compressive residual stresses of crack tip. In low $\Delta$K region, it is estimated that the effects of residual stresses for da/dN are great. In region II, the da/dN of weldments in as weld state was lower than that of the base metal. Though da/dN of Weldments in PWHT state was similar to that of the base metal. The constant of power law, m in two states consisted with the base metal. Therefore , it is estimated that the value of m is not affected by residual stresses. Fatigue crack growth behavior of weldments consisted with the base metal considering the effective stress intensity factor range($\Delta$K$\sub$eff/) included the effect of initial residual stress(Kres). Thus, we can predict the fatigue crack growth behavior of weldment by knowing the distribution of initial residual stress at the crack tip.

  • PDF

세라믹/금속 접합재의 잔류응력 해석 (Analysis of Residual Stress of Ceramic/Metal Joint)

  • 박영철;허선철;김광영
    • 비파괴검사학회지
    • /
    • 제14권1호
    • /
    • pp.7-15
    • /
    • 1994
  • 동을 중간재로 하는 $Si_3N_4/SUS304$ 접합재의 접합계면 근방의 잔류응력 분포를 유한요소법과 X선 응력측정법을 이용하여 해석을 하였다. 그 결과, 접합재의 세라믹부 계면 근방의 잔류응력 분포를 정량적으로 밝혀낼 수 있었다. 세라믹부에 발생되는 접합 잔류응력은 접합계면 근방에서 대단히 크게 나타났으며, 특히 최대인장 잔류응력 ${\sigma}_x$는 단부에서 발생하였다. 한편, ${\sigma}_x$는 접합계면 근방에서 3차원분포를 하고 있기 때문에 2차원 유한요소 해석결과와는 대단히 다른 값을 나타내고 있으며, 특히 시험편 중앙부의 계면 근방에서는 X선 실측결과가 인장 잔류응력임에 반하여 2차원 유한요소 해석결과는 압축 잔류응력으로 계산되어짐을 알았다. 따라서, 이와같은 3차원 분포를 하고 있는 접합계면 근방의 잔류응력 ${\sigma}_x$보다 간편하고 정확하게 예측할 수 있는 유한요소 해석모델에 대하여 서로 검토하였다.

  • PDF

잔류응력이 응력세기계수와 피로균열성장율에 미치는 영향 (The Effect of Residual Stress on Stress Intensity Factor and Fatigue Crack Growth Rate)

  • 이강용;김홍기
    • 대한조선학회지
    • /
    • 제21권1호
    • /
    • pp.43-47
    • /
    • 1984
  • The purpose of this paper is to investigate theoretically the effect of residual stress due to welding in stress intensity factor of a plate containing the Model I Crack in different crack size and location, and on fatigue crack growth rate. The initiation of crack is found to be possible only in the region of tensile residual stress. The most dangerous crack has the values of d/b and a/b equal to about 0.6 and 1.0, respectively, where d/b is the ratio of distance from the crack to welding bead and the width of tensile residual stress region and a/b is the ratio of crack length and tensile residual stress region. The crack perpendicular to and on the line of welding bead and with a/b equal to about 0.6 has maximum stress intensity factor. The theoretical fatigue crack growth rate under residual stress and applied stress, which is obtained from Forman's Law by stress superposition, is relatively in good agreement with Glinka's[8] experimental value. The fatigue crack growth is shown to be retarded due to residual stress distribution.

  • PDF

고 탄소 미세 강선의 기계적 특성에 미치는 잔류 응력과 표면 결함의 영향 (Effects of Residual Stress and Surface Defect on the Mechanical Properties of the High Carbon Steel Filaments)

  • 양요셉;배종구;박찬경
    • 한국소성가공학회:학술대회논문집
    • /
    • 한국소성가공학회 2008년도 추계학술대회 논문집
    • /
    • pp.134-137
    • /
    • 2008
  • The effects of residual stress and surface defects on the mechanical properties of the high carbon steel filament used for the automotive tire have been experimentally investigated. The samples were fabricated with annealing temperature. The residual stress was measured by focused ion beam and strain mapping software which has advantages, such as data with high accuracy and fast data acquisition time. Mechanical properties, such as tensile strength and fatigue resistance, were gradually increased up to $200^{\circ}C$ and then slightly decreased. From the measurement of residual stress and level of surface defect, it was revealed that the critical factor was varied with different temperature region. That is, the fatigue resistance increased due to decreasing the residual stress and decreased due to increasing the size and distribution of surface defect.

  • PDF

외부하중에 의한 용접 체결부의 잔류응력 이완 특성 해석에 관한 연구 (Analysis of Residual Stress Relaxation in Welded Joints due to External Loads)

  • 장창두;송하철;조영천
    • 한국해양공학회:학술대회논문집
    • /
    • 한국해양공학회 2003년도 추계학술대회 논문집
    • /
    • pp.167-170
    • /
    • 2003
  • Thermal elastic-plastic analysis was performed to assess the initial residual stress distribution of welded joints considering temperature dependent material properties. The test model was the idealized boxing fillet specimen, frequently appeared in the joints of longitudinal and transverse members of ship structure. Residual stress relaxations due to external loads were analyzed by subsequent elastic-plastic analysis considering loading and unloading steps, and the characteristics of residual stress relaxations were discussed with the levels of external loads. Additionally, to define the fatigue life of crack initiation and propagation, the S-N data for each crack length were appraised.

  • PDF