복합응력이 작용하는 균열 배관에 대한 천이 크리프 조건에서의 C(t)-적분 예측 (I) = 탄성-크리프

다국어 초록 (Multilingual Abstract)

The C(t)-integral describes amplitude of stress and strain rate field near a tip of stationary crack under transient creep condition. Thus the C(t)-integral is a key parameter for the high-temperature crack assessment. Estimation formulae for C(t)-integral of the cracked component operating under mechanical load alone have been provided for decades. However, high temperature structures usually work under combined mechanical and thermal load. And no investigation has provided quantitative estimates for the C(t)-integral under combined mechanical and thermal load. In this study, 3-dimensional finite element analyses were conducted to calculate the C(t)-integral of elastic-creep material under combined mechanical and thermal load. As a result, redistribution time for the crack under combined mechanical and thermal load is re-defined through FE analyses to quantify the C(t)-integral. Estimates of C(t)-integral using this proposed redistribution time agree well with FE analyses results.

목차 (Table of Contents)

• Abstract
• 1. 서론
• 2. 기계하중에 대한 C(t)-적분 예측
• 3. 복합하중에 대한 유한요소 해석
• 4. 복합하중에 대한 탄성 C(t)-적분 예측
• 5. 결론
• 후기
• 참고문헌

참고문헌 (Reference)

1 김윤재, "축방향 관통균열이 존재하는 곡관의 한계 하중 및 공학적 J-적분 예측" 대한기계학회 31 (31): 562-569, 2007

2 김윤재, "직관과 곡관의 경계 용접부에 존재하는 원주방향 표면균열에 대한 탄소성 파괴역학 해석" 대한기계학회 31 (31): 710-717, 2007

3 송태광, "열하중 및 기계하중이 작용하는 원주 방향 균열 배관에 대한 V-계수 평가" 대한기계학회 32 (32): 1123-1131, 2008

4 허남수, "광범위 크리프 조건에 대한 관통균열 배관의 크리프 파괴역학 해석" 대한기계학회 27 (27): 890-897, 2003

5 Harper, M. P., "The Use of the C* Parameter in Predicting Creep Crack Propagation Rates" 12 : 167-199, 1977

6 Joch, J., "The Development of Creep Singular Fields for Defects in Thermally Loaded Structures" 15 (15): 685-693, 1992

7 Riedel, H., "Tensile Cracks in Creeping Solids, Fracture Mechanics : Twelfth Conference" 700 : 112-130, 1980

8 Nikbin, K. M., "Relevance of Nonlinear Fracture Mechanics to Creep Cracking, Cracks and Fractured" 601 : 47-62, 1976

9 British Energy Generation Ltd., "R6:Assessment of the Integrity of Structures Containing Defects,Rivision 4"

10 "R5: An Assessment Procedure for the High Temperature Response of Structures. Revision 2, British Energy"

11 Webster, G. A., "High Temperature Component Life Assessment" Chapman & Hall 1994

12 Lei, Y., "Finite Element RCC-MR Creep Analysis of Circumferentially Cracked Cylinders Under Combined Residual Stress and Mechanical load, in British Energy Report" British Energy Generation Limited. 2008

13 Kim, Y. J., "Finite Element Analysis to Assess the Effect of Initial Plasticity on Transient Creep for Defects Under Mechanical Loading" 78 : 1021-1029, 2001

14 Kim, J. S., "Estimation of C*-Integral for Defective Components with General Creep Deformation Behaviors" 26 (26): 795-802, 2002

15 Song, T. K., "Estimation of C(t)- Integral in Transient Creep Condition for Pipe with Crack Under Combined Mechanical and Thermal Stress (Part II : Elastic-plastic-creep), Submitted to Transactions of the KSME(A)" 2009

16 Ainsworth, R. A., "Crack tip Fields Under Non-Steady Creep Conditions - II. Estimates of Associated Crack Growth" 13 (13): 277-285, 1990

17 Ainsworth, R. A., "Crack Tip Fields Under Non-Steady Creep Conditions-I. Estimates of the Amplitude of the Fields" 13 (13): 263-276, 1990

18 Kim, Y. J., "Contour Integral Calculations for Generalized Creep Laws Within ABAQUS" 78 : 661-666, 2001

19 Miller, A. G., "Consistency of Numerical Results for Power-Law Hardening Materials and the Accuracy of the Reference Stress Approximation for J" 32 (32): 233-247, 1989

20 Kumar, V., "An Engineering Approach for Elastic Plastic Fracture Analysis, in EPRI report" 1931

21 Ehlers, R., "A Finite Element Analysis of Creep Deformation in a Specimen Containing a Macroscopic Crack, In Proc. Fifth Int. Conf. on Fracture (Edited by D. Francois)" Pergamon Press 691-698, 1981