• 제목/요약/키워드: 십자형 시편

검색결과 6건 처리시간 0.021초

이축하중을 받는 십자형 시편의 파괴인성 및 구속효과 평가 (Evaluation of Fracture Toughness and Constraint Effect of Cruciform Specimen under Biaxial Loading)

  • 김종민;김민철;이봉상
    • 한국압력기기공학회 논문집
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    • 제12권1호
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    • pp.62-69
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    • 2016
  • Current guidance considers that uniaxially loaded specimen with a deep crack is used for the determination of the ductile-to-brittle transition temperature. However, reactor pressure vessel is under biaxial loading in real and the existence of deep crack is not probable through periodic in-service-inspection. The elastic stress intensity factor and the elastic-plastic J-integral which were used for crack-tip stress field and fracture mechanics assessment parameters. The difference of the loading condition and crack geometry can significantly influence on these parameters. Thus, a constraint effect caused by differences between standard specimens and a real structure can over/underestimate the fracture toughness, and it affects the results of the structural integrity assessment, consequentially. The present paper investigates the constraint effects by evaluating the master curve $T_0$ reference temperature of PCVN (Pre-cracked Charpy V-Notch) and small scale cruciform specimens which was designed to simulate biaxial loading condition with shallow crack through the fracture toughness tests and 3-dimensional elastic-plastic finite element analyses. Based on the finite element analysis results, the fracture toughness values of a small scale cruciform specimen were estimated, and the geometry-dependent factors of the cruciform specimen considered in the present study were determined. Finally, the transferability of the test results of these specimens was discussed.

2축 십자형 시편을 이용한 알루미늄 합금 판재의 항복곡면에 대한 연구 (Study on the Yield Locus of Aluminum Alloy Sheet Using Biaxial Cruciform Specimens)

  • 신효동;박진기;박춘달;김영석
    • 소성∙가공
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    • 제18권5호
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    • pp.416-421
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    • 2009
  • The applications of the aluminum alloy sheets to the auto-body panels are dramatically increasing for weight reduction of the automobiles. However, low formability of the aluminum alloy sheet compared to the steel sheet can be obstacles in tool manufacturing processes. Therefore, many of yield criteria for the anisotropic materials such as the aluminum alloy sheet have been observed. In this study, the biaxial tensile test and FLD test for the aluminum alloy sheet are performed. The results are compared with Hill's 1948 and Hill's 1990 models by means of theoretical predictions. Finite element analysis was also performed using the proposed method for the real panel.

2축 십자형 시편을 이용한 알루미늄 합금 판재의 항복곡면에 대한 연구 (Study on the Yield Locus of Aluminum alloy sheet Using Biaxial Cruciform Specimens)

  • 신효동;박진기;박춘달;노현철;윤국태;임희택;김영석
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2009년도 춘계학술대회 논문집
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    • pp.164-167
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    • 2009
  • The applications of the aluminum alloy sheets to the auto-body panels are dramatically increasing for weight reduction of the automobiles. However, low formability of the aluminum alloy sheet compare to the steel sheet can be obstacles in tool manufacturing process. Therefore, much of yield criteria for the anisotropic material such as the aluminum alloy sheet have been observed. In this study, the biaxial tensile test and FLD test for the aluminum alloy sheet are performed. The results are compared with Hill's 1948 and Hill's 1990 model by means of theoretical predictions. Finite element analysis also performed using the proposed method for the real panel.

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철강 재료의 2축 비등방향 잔류응력 평가를 위한 연속압입시험의 최적조건 선정 (Optimum Selection of the Advanced Indentation Technique for the Evaluation of Non-equip-biaxial Residual Stress in Steel Materials)

  • 유승종;김주현;박주승;권동일
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.1774-1779
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    • 2005
  • Most of materials receive force in using, therefore, the characteristics of materials must be considered in system design not to occur deformation or destruction. Mechanical properties about materials can be expressed as responsible level of material itself under the exterior operation. Main mechanical properties is strength, hardness, ductility and stiffness etc. Currently, among major measure facilities to measure such mechanical properties, advanced indentation technique has focused in industrial areas as reason of nondestructive and easy applications for mechanical tensile properties and evaluation of residual stress of materials. This study is to find the optimum experimental condition about residual stress advanced indentation technique for accurate analysis of the welded joint of steel materials through indentation load-depth curve obtained from cruciform specimen experiment. Optimum selection was applied to the welded joint of real steel materials to give non-equi-biaxial stress state and compared with general residual stress analyzing method for verification.

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연속압입시험의 최적조건 선정을 통한 철강재료의 용접부 잔류응력 평가 (The Evaluation of Residual Stresses in the Welded Joint of Steel Materials by the Optimum Selection of the Advanced Indentation Technique)

  • 유승종;김주현
    • 한국정밀공학회지
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    • 제24권2호
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    • pp.118-126
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    • 2007
  • Most of materials receive forces in use so that the characteristics of materials must be considered in system design to prevent deformation or destruction. Mechanical properties of materials can be expressed as responsible level of material itself under the exterior operation. Main mechanical properties are strength, hardness, ductility and stiffness. Currently, among major measure facilities to measure the mechanical properties, advanced indentation technique has important use in industrial areas due to nondestructive and easy applications for mechanical tensile properties and evaluation of residual stress of materials. This study is to find the optimum experimental condition about residual stress advanced indentation technique for accurate analysis of the welded joint of steel materials through indentation load-depth curve obtained from cruciform specimen experiment. Optimum selection was applied to the welded joint of real steel materials to find out non-equi-biaxial stress state and the results were compared with general residual stress analyzing method fur verification.

십자형 용접 시편의 3차원 용접 잔류응력 분포 예측에 관한 연구 (A Study of Predicting 3-dimensional Welding Residual Stresses Distribution for T-joint Fillet Specimen)

  • 유미지;이장현;황세윤;김경수;김성찬
    • Journal of Welding and Joining
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    • 제28권2호
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    • pp.84-90
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    • 2010
  • Fillet welding accounts for about 80% of all constructing process of ship and ocean structure. T-joint is one of the typical shapes which are frequently reported to experience the fatigue damage when the marine structure meets the storm loads. The fatigue damage is affected by the magnitude of residual stresses on the weld. Recently, many shipping registers and design guidances have required that the fatigue strength assessment method should be compensated by the effect of the residual stress in case that the random loading or storm loading is applied to the marine vessels. This study suggests the computational procedure to analyze the residual stresses of T-joint specimen that is frequently reported to get damaged by the storm loading. Experiment by XRD as well as the 3-D computational welding model is presented in order to get the profile of residual stress. Throughout the comparison of experimental result with the computational result, the computational model was validated. Thereafter, characteristics of he residual stresses in the joint are discussed.