• Title, Summary, Keyword: stress redistribution

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Redistribution of Welding Residual Stress and its Effects on Fatigue Crack Propagation (피로균열이 진전할 때 용접잔류응력의 재분포와 그 영향)

  • 이용복;조남익
    • Journal of Welding and Joining
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    • v.13 no.4
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    • pp.155-162
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    • 1995
  • Redistribution of residual stress and its effects during fatigue crack propagates from tensile residual stress region in weldment are investigated. Tests are performed by using welded CCT specimens of structual rolling steel (SS400) and it makes fatigue crack propagate from tensile residual stress region. For this study tension-tension loading type is selected by external loading condition and magnetizing stress indicator is used correctly to measure redistribution of residual stress according to fatigue crack growth and number of loading cycles. From this result, it is proved that redistribution of residual stress is mainly consist of residual stress released by fatigue crack growth. When fatigue crack propagates from tensile residual stress region residual stress are redistributed and it makes fatigue crack growth rate largely increase. Fatigue crack growth rate is low in case of redistributed residual stress compare with initial distributed residual stress.

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An Analysis of the Redistribution of Residual Stress Due to Crack Propagation Initially Through Residual Tensile Stress Field by Finite Element Method (인장잔류응력장으로부터 피로균열이 전파하는 경우 잔류응력의 재분포거동에 대한 해석적 검토)

  • 김응준;박응준;유승현
    • Journal of Welding and Joining
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    • v.21 no.7
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    • pp.71-77
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    • 2003
  • In this study, an investigation based on the superposition principle to predict residual stress redistribution caused by crack propagation itself initially through residual tensile stress field was performed by finite element method. The tendency in residual stress redistribution caused by crack propagation recognized both from the analytical results and experimental result was the residual stress concentration consecutively occurred in the vicinity of crack tip even the situation that the crack propagated to the region initially residual compressive stress existed. The software for the analysis is ABAQUS, which is a general purpose finite element package. The analytical method that attempt to take the plastic deformation at the crack tip due to tensile residual stress into the consideration of residual stress redistribution caused by crack propagation was proposed. The plastic zone size at the tip of fatigue crack and redistributed residual stresses were calculated by finite element method on the bases of the concept of Dugdale model. Comparing these analytical results with experimental results, it is verified that the residual stress redistribution caused by crack propagation can be predicted by finite element method with the proposed analytical method.

An Evaluation of Residual Stress Redistribution in the Welding Residual Stress Field Caused by Fatigue Crack Propagation by Finite Element Method (용접잔류응력장에서 피로균열의 전파에 따른 잔류응력 재분포에 대한 해석적 평가)

  • Park, Eung-Joon;Kim, Eung-Joon
    • Journal of Welding and Joining
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    • v.26 no.6
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    • pp.92-96
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    • 2008
  • An investigation was performed to predict residual stress redistribution for the crack propagation initially through tensile residual stress field. The analytical method, which is based on Dugdale model by finite element analysis using elastic analysis method considering the superposition principle, was proposed to estimate the redistribution of residual stress caused by crack propagation. The various aspect of distribution of residual stress caused by crack propagation was examined based on the configuration change of specimen. The analysis results show that the aspect of redistribution of residual stress caused by crack propagation depends on the width of the specimen provided that the initial distribution of residual stress is identical.

Effect of the welding residual stress redistribution on impact absorption energy (재분포된 용접잔류응력이 충격흡수에너지에 미치는 영향)

  • Yang, Zhaorui;Lee, Youngseog
    • Journal of Welding and Joining
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    • v.33 no.1
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    • pp.72-79
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    • 2015
  • Evaluation of fracture toughness of welded structures has a significant influence on the structural design. However the residual stresses is redistributed while the welded structures is cut for preparing specimens. This study investigated an effect of the welding residual stress redistribution on the impact absorption energy of Charpy specimen. SA516Gr70 steel plate by at the flux cored arc welding (FCAW) and gas tungsten arc welding(GTAW) was cutting. Specimens for Charpy impact testing were taken from the welded plate. Two material removal mechanisms (wire cutting and water jet) were used to make the specimens. Welding residual stress and redistribution residual stress were measured using the XRD (X-Ray Diffraction) method. The amount of redistribution of residual stress depends on the different material removal mechanism. Redistribution of residual stress of reduced the impact absorption energy by 15%.

Numerical Modeling for the Analysis of Residual Stress Redistribution due to Crack Propagation (균열 진전에 따른 잔류응력 재분포 해석을 위한 수치해석 모델링)

  • 송하철;이창현;장창두
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.245-251
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    • 1999
  • As the crack grows in the residual stress fields, the distribution of the residual stress is changed. In this study, a finite element modeling technique is developed to simulate the redistribution of residual stress due to crack propagation. To certify the accuracy, the crack propagation tests were carried out and tile effective stress intensity factor range was evaluated considering the redistribution of residual stress from the FE analysis.

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A Study on Fatigue Behavior considering Effects of Redistributing Compressive Residual Stress and Crack Closure in SS330 Weldment (SS330 용접재에서 재분포 압축잔류응력 및 균열닫힘의 영향을 고려한 피로거동에 관한 연구)

  • 이용복
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.6 no.2
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    • pp.26-33
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    • 1997
  • In this study effect of residual stress and its redistribution in weldment on the fatigue crack propagation was investigated. Fatigue tests were conducted by the center notched specimens machined with welded plate. The residual stress and its redistribution after the crack growth were measured by the magnetizing stress indicator and hole-drilling method. Fatigue crack propagation was estimated by the specimens having residual stress redistributed after the cracks growth and having the effects of crack closure. Crack growth rates were predicted and compared with experimental results. It had been found that the predicted crack propagation rates have a good agreement with experimental results when the redistribution of residual stress was considered.

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Assessment of Fatigue Crack Propagation Considering the Redistribution of Residual Stress due to Overload

  • Jang, Chang-Doo;Leem, Hyo-Kwan;Choi, Yeoung-Dal;Bang, Jun-Kee;So, Ha-Young
    • Journal of Ship and Ocean Technology
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    • v.11 no.2
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    • pp.26-33
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    • 2007
  • For the assessment of the retardation of fatigue crack propagation behavior due to overload, new FE analysis algorithms considering compressive residual stress redistribution near crack tip was proposed in this paper. The size of plastic zone near crack tip was obtained by elasto-plastic analysis and it was compared with Irwin's equation. The amount of residual stress redistribution was assessed by subsequent elasto-plastic analysis, and the difference of residual stress distributions between constant amplitude load and overload was obtained. In the analysis of fatigue crack propagation, the applied SIF range was evaluated by ASTM E647, and the effect of residual stresses on crack propagation was considered using the effective SIF concept. The test results of crack propagations were compared with the predicted data obtained by the analysis.

A Study on Fatigue Behavior Considering Effects of Redistributing Tensile Residual Stress and Crack Closure in SS330 Weldment (SS330 용접재에서 재분포 잔류응력 및 균열닫힘영향을 고려한 파로거동에 관한 연구)

  • Lee, Yong-Bok;Jeong, Jin-Seong;Jo, Nam-Ik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.7
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    • pp.2234-2245
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    • 1996
  • In this study residual stress in weldment was considered about the effect on the fatigue propagation and about the effect of redistribution of residual stress. Then, fatigue tests were conducted by the center notched specimens machined with welded plate. The residual stress and its redistribution after the crack growth were measured by the magnetizing stress indicator and hole-drilling method. Fatigue crack propagation was estimated by the specimens having residual stress redistributed after the cracks growth and having the effects of crack closure. Crack growth rates were predicted and compared with experimental results. It had been found that the predicted crack propagation rates have a good agreement with experimental results when the redistribution of residual stress was considerd.

A Study on Evaluation of Residual Stress Redistribution for FCA Butt Weldment of Ultra-Thick YP47 Steel Plate under Tensile Cyclic Load (반복 인장 하중을 받는 YP47 극후판 Butt 용접부의 잔류응력 재분포에 관한 연구)

  • Kang, Bong Gook;Lee, Dong Ju;Shin, Sang Beom
    • Journal of Welding and Joining
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    • v.34 no.4
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    • pp.28-33
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    • 2016
  • The purpose of this study is to evaluate the redistribution of transverse residual stress in the multi-pass FCA butt weld of YP47 in the hatch coaming top plate of ultra large size containership under the tensile cyclic load. In order to do it, the configuration of modified H type specimen including restraint length was first designed to simulate the restraint condition of the butt weld in hatch coaming top plate. FE analysis procedure for evaluating the transverse residual stress was verified by comparing the calculated mean and surface residual stresses with the measured results in the test specimen. After that, the effect of the cyclic load on the redistribution of transverse residual stress was evaluated by comprehensive FEA. From the results, it was found that although the maximum transverse residual stress decreased with an increase in the applied maximum load, the effect of the cyclic load on the mean residual stress is small enough to be negligible. It is because the maximum stress of the ship corresponding to the probability of 10E-8 is less than 70% of yield stress of the weld.

Numerical Analysis of Residual Stress Redistribution due to Fatigue Crack Propagation of Weld Zone (용접부의 균열진전에 따른 잔류응력 재분포 해석)

  • 이동형;구병춘
    • Proceedings of the KSR Conference
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    • pp.225-231
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    • 2002
  • The problem of welding stresses and fatigue behavior is the main concerns of welding research fields. The residual stresses and distortion of structures by welding is exert negative effect on the safety of mechanical structures. That is, expansion of material by high temperature and distortion by cooling during welding process is caused of tensile and compressive residual stresses on welding material, and this residual stresses reduce fracture and fatigue strength of welding structures. The accurate prediction of residual stress and redistribution due to fatigue crack propagation of weld zone is very important to improve the quality of weldment. In this study, a finite element modeling technique is developed to simulate the redistribution of residual stresses due to fatigue crack propagation of weld zone.

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