• Title, Summary, Keyword: J-integral

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J-integral for subsurface crack in circular plate with inner hole under rolling and sliding contact (구름 및 미끄럼 접촉하의 중공원판의 표면하층균열에 대한 J-적분)

  • Lee, Kang-Yong;Kim, June-Yeop
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.7
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    • pp.1149-1155
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    • 1997
  • J-integral for a subsurface horizontal crack in a circular plate with an inner hole under rolling line contact is evaluated according to loading positions with various load conditions, crack length and crack location. Two-dimensional crack is modeled, and the relation between Tresca stress for uncracked model and J-integral is discussed. The loading location which gives the maximum J-integral depends on load condition and crack location, and the presence of friction force increases Tresca stress and J-integral near the surface. Regardless of friction force, crack location that gives maximum J-integral is the same as that of maximum Tresca stress in an uncracked model, and the value of J-integral is propotional to crack length. It is also showed that the variation of an inner radius of a disk does not effect J-integral value.

Development of 3-D J-Integral Calculation Method for Structural Integrity Evaluation (기기 건전성 평가를 위한 3차원 J-적분 계산 전산코드 응용평가 연구)

  • Kim, Young-Jin
    • Proceedings of the KIEE Conference
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    • pp.450-454
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    • 1999
  • In order to evaluate the integrity of nuclear power plants, J-integral calculation is crucial. For this purpose, finite element method is popularly used to obtain J-integral. However, high cost time consuming preprocess should be performed to design the finite element model of a cracked structure. Also, the J-integral should be verified by alternative method since it may differ depending on the calculation method. The objective of this paper is to develop a three-dimensional elastic-plastic J-integral analysis system which is named as EPAS. The EPAS program consists of an automatic mesh generator for a through-wall crack and a surface crack, a solver based on ABAQUS program, and a J-integral calculation program which provides DI(Domain Integral) and EDI(Equivalent Domain Integral) based J-integral calculation. Using the EPAS program, an optimized finite element model for a cracked structure can be generated and corresponding J-integral can be obtained subsequently.

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J-Integral under Transient Temperature State (천이온도 상태에서의 J적분)

  • 이강용;박정수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.1781-1791
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    • 1991
  • For the cracked plate under transient temperature distribution, J-integral is expressed in the form of line integral by using convolution integral. The J$_{1}$ integral is calculated for a through line center cracked steel plate under thermal and mechanical loading conditions and the calculated values are in good agreement with previous results. The effect of inertia term on the J$_{1}$ integral is not negligible for a glass but for a steel. For the glass plate, the rates of J$_{1}$ integral value to time increase if the values of material properties such as specific heat, thermal conductivity, thermal diffusivity and Young`s modulus as well as crack length and temperature difference in cracked edge increase.

Development of a Three Dimensional Elastic Plastic Analysis System for the Integrity Evaluation of Nuclear Power Plant Components (원자력발전소 주요기기의 건전성 평가를 위한 3차원 탄소성 해석 시스템의 개발)

  • Huh, Nam-Su;Im, Chang-Ju;Kim, Young-Jin;Pyo, Chang-Ryul;Park, Chi-Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.8
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    • pp.2015-2021
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    • 2000
  • In order to evaluate the integrity of nuclear power plant components, the analysis based on fracture mechanics is crucial. For this purpose, finite element method is popularly used to obtain J-integral. However, it is time consuming to design the finite element model of a cracked structure. Also, the J-integral should be verified by alternative methods since it may differ depending on the calculation method. The objective of this paper is to develop a three-dimensional elastic-plastic J-integral analysis system which is named as EPAS program. The EPAS program consists of an automatic mesh generator for a through-wall crack and a surface crack, a solver based on ABAQUS program, and a J-integral calculation program which provides DI (Domain Integral) and EDI (Equivalent Domain Integral) based J-integral calculation. Using the EPAS program, an optimized finite element model for a cracked structure can be generated and corresponding J-integral can be obtained subsequently.

Analysis of the J-integral for Two-dimensional and Three-dimensional Crack Configurations in Welds of Steel Structure (강구조물 응접접합부의 2차원 및 3차원 균열에 대한 J-적분 해석)

  • 이진형;장경호
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.270-277
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    • 2004
  • In this paper, path-independent values of the J-integral in the fininte element context for arbitrary two-dimensional and three-dimensional crack configurations in welds are presented. For the fracture mechanics analysis of cracks in welds, residual stress analysis and fracture analysis must be performed simultaneously. In the analysis of cracked bodies containing residual stress, the usual domain integral formulation results in path-dependent values of the J-integral. This paper discusses modifications of the conventional J-integral that yield path independence in the presence of residual stress generated by welding. The residual stress problem is treated as an initial strain problem and the J-integral modified for this class of problem is used. And a finite element program which can evaluate the J-integral for cracks in two-dimensional and three-dimensional residual stress bearing bodies is developed using the modified J-integral definition. The situation when residual stress only is present is examed as is the case when mechanical stresses are applied in conjunction with a residual stress field.

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Breakdown Analysis of Piezoelectric Ceramics Using J Integral (J 적분을 이용한 압전세라믹의 절연파괴 해석)

  • Lin, Song;Kim, Yu-Hwan;Beom, Hyeon-Gyu
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.1
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    • pp.105-111
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    • 2009
  • Dielectric breakdown in piezoelectric ceramics is analyzed by using the three dimensional J integral. The J integral is shown to be a path-independent surface integral for a conductive tubular channel in a piezoelectric material. J integrals are also numerically calculated for conductive defects and tubular channels in piezoelectric ceramics through finite element analysis.

Fracture mechanics analysis of a crack in a weld of dissimilar steels using the J-ingegral (J-적분을 이용한 이종강재 용접접합부 균열의 파괴역학적 해석)

  • 이진형;장경호
    • Proceedings of the KWS Conference
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    • pp.264-266
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    • 2004
  • for the kぉ mechanics analysis of a crack in a weld of dissimilar steels, residual stress analysis and fracture analysis must be performed simultaneously. The standard definition of the J-integral leads to a path dependent value in the presence of a residual stress field. And unlike cracks in homogeneous materials, a bimaterial interface crack always induces both opening and shearing modes of stress in the vicinity of the crack tip. Therefore, it is necessary to develope a path independent J-integral definition for a crack in a residual stress field generated by welding of dissimilar steels. This paper addresses the modification of the Rice-J-integral to produce a path independent J-integral when residual stresses due to welding of dissimilar steels and external forces are present. The residual stress problem is heated as an initial stain problem and the J-integral proposed for this class of problems is used And a program which can evaluate the 1-integral for a crack in a weld of dissimialr steels is developed using proposed J-integral definition.

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Fracture Analysis of Welded Plates using the J-integral (J-적분을 이용한 용접구조물의 파괴해석)

  • 심용래
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.173-179
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    • 1996
  • Study of weldment fracture behavior includes thermal analysis, residual stress analysis, and fracture analysis. The J-integral loses its path-independency in a residual stress field. Therefore, it is necessary to develop a program to calculate the J-integral in a welded plate. In this study, theoretical formulation and program were developed for the evaluation of the J-integral at the crack tip of weldments. To verify equations and program, welded thin plate and thick plate were used to calculate residual stress and the J-integral.

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Fracture Mechanics Analysis of a Interface Crack in the Weld of Dissimilar Steels using the J-integral (J-적분을 이용한 이종강재 용접접합부 계면균열의 파괴역학적 해석)

  • Lee Chin-Hyung;Chang Kyong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.4
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    • pp.423-431
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    • 2004
  • For the fracture mechanics analysis of cracks in welds of dissimilar steels, residual stress analysis and fracture analysis must be performed simultaneously. The standard definition of the J -integral leads to a path dependent value in the presence of a residual stress field. And unlike cracks in homogeneous materials, a bimaterial interface crack always induces both opening and shearing modes of stress in the vicinity of the crack tip. Therefore, it is necessary to develope a path independent J-integral definition for a crack in a residual stress field generated by welding of dissimilar steels. This paper addresses the modification of the Rice-J-integral to produce a path independent J -integral when residual stresses due to welding of dissimilar steels and external forces are present. The residual stress problem is treated as an initial strain problem and the J-integral proposed for this class of problems is used. And a program which can evaluate the J -integral for a crack in a weld of dissimialr steels is developed using proposed J integral definition.

Fracture Mechanics Analysis of a Crack in the Weld using the J-integral (J-적분을 이용한 용접접합부 균열의 파괴 역학적 해석)

  • Chang, Kyong Ho;Lee, Chin Hyung
    • Journal of Korean Society of Steel Construction
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    • v.17 no.2
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    • pp.243-251
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    • 2005
  • The fracture mechanics analysis of a crack in a weld must consider residual stress generated during welding. The standard definition of the J-integral requires a path dependent value in the presence of a residual stress field. Therefore, it is necessary to develop a path independent J-integral definition for a crack in a residual stress field. This paper addresses the modification of the Rice-J-integral to produce a path- independent J-integral when residual stresses and external forces are present. The residual stress problem is treated as an initial strain problem and the J-integral proposed for this type of problems is used. A program which can evaluate the J-integral for a crack in a weld is developed using the proposed J-integral definition. The situation when only residual stress is present is examined as is the case when mechanical stresses are applied in conjunction with a residual stress.