DOI QR코드

DOI QR Code

Consideration of Constraint Effect of Surface Cracks Under PTS Conditions Using J-Q Approach

PTS 사고하에서 J-Q해석법을 이용한 표면균열의 구속효과 고찰

  • Published : 2002.01.01

Abstract

In recent years, the integrity of reactor Pressure Vessel(RPV) under pressurized thermal shock (PTS) accident has been treated as one of the most critical issues. Under PTS condition, the combination of thermal and mechanical stress by steep temperature gradient and internal pressure causes considerably high tensile stress at the inside of RPV wall. As a result, cracks on inner surface of RPV may experience elastic-plastic behavior which can be characterized by J-integral. In such a case, however, J-integral may possibly lose its vapidity due to the constraint effect. The degree of constraint effect is influenced by the loading mode, crack geometry and material properties. In this paper, in order to investigate the effect of clad thickness and crack geometry on constraint effect, three dimensional finite element analyses were performed for various surface cracks. Total of 27 crack geometries were analyzed and results were presented by a two-parameter characterization based on the J-integral and the f-stress.

Keywords

Pressurized Thermal Shock;J-Integral;Constraint Effect;Surface Crack;J-Q Approach;Q-Stress

References

  1. Shih, C.F., 1983, Tables of Hutchinson-Rice-Rosengren Singular Field Quantities, Brown University
  2. Hibbit, Karlsson & Sorensen Inc., 1998, ABAQUS/Standard ver. 5.8-1.
  3. 정명조, 2000, '원자로 용기의 가압열충격 Round Robin 해석,' 한국원자력안전기술원, KINS/RR-029
  4. 김진수,구본걸, 최재붕, 김영진, 박윤원, 2001, '가압열충격 사고시 클래드 하부균열 안전성 평가 방법에 관한 연구,' 대한기계학회논문집, 제25권, 제7호, pp. 1139-1146
  5. 심도준, 최재봉, 장영균, 김영진, 김철만, 2000, '구속효과를 고려한 가스배관 결함의 2차원적 파괴거동 해석에 관한 연구,'대한기계학회논문집, 제25권, 제1호, pp. 61-69
  6. 김진수, 최재붕, 김영진, 2000, '구속효과를 고려한 원자로 압력용기 균열선단에서의 응력분포 예측,' 대한기계학회논문집, 제25권, 제4호, pp. 756-763
  7. Hutchinson, J. W., 1968, 'Singular Behavior at the End of Tensile Crack Tip in a Hardening Material,' Journal of the Mechanics and Physics of Solids, Vol. 16, pp. 13-31 https://doi.org/10.1016/0022-5096(68)90014-8
  8. Rice, J. R. and Rosengren, G. F., 1968, 'Plane Strain Deformation near a Crack Tip in a Power-Law Hardening Material,' Journal of the Mechanics and Physics of Solids, Vol. 16, pp. 1-12 https://doi.org/10.1016/0022-5096(68)90013-6
  9. Miyazaki, N., Ikeda, T., and Ochi, K., 1996, 'Constraint Effects of Clad on Underclad Crack,' Journal of Pressure Vessel Technology, pp. 480-483
  10. Shum, D.K,Theiss, T.J. and Rolfe, S.T., 1994, 'Application of J-Q Fracture Methodology to the Analysis of Pressurized Thermal Shock in Reactor Pressure Vessels,' Fracture Mechanics: Twenty-Fourth Volume, ASTM STP 1207, pp. 152-168
  11. O'Dowd, N. P. and Shih, C. F., 1991, 'Family of Crack-Tip Fields Characterized by a Triviality Parameter- Structure of fields,' Journal of Mechanics and Physics of Solids, pp. 989-1015 https://doi.org/10.1016/0022-5096(91)90049-T
  12. Moinereau, D. Faidy, C.;Bhandari, S. Guichard, D. Valeta, M.P. and Courtois, M., 1998, 'NESC Spinning Cylinder Thermal Shock Experiment. French Contribution to the Pre Test Fracture Analysis Evaluation,' 98 ASME PVP-Vol. 362, pp. 261-279
  13. Betegon, C. and Hancock, J.W., 1991, 'Two-Parameter Characterization of Elastic-Plastic Crack-Tip Fields,' Journal of Applied Mechanics, vol. 58, pp. 104-110 https://doi.org/10.1115/1.2897135