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Elastic-Plastic J Estimations for Pipes with Off-Centred Circumferential Through-Wall Cracks

비대칭 원주방향 관통균열 배관의 탄소성 J-적분 계산식

  • 심도준 (성균관대학교 기계공학부) ;
  • 허남수 (성균관대학교 기계공학부) ;
  • 김윤재 (성균관대학교 기계공학부) ;
  • 김영진 (성균관대학교 기계공학부)
  • Published : 2003.07.01

Abstract

This paper provides approximate J estimates for off-centred, circumferential through-wall cracks in cylinders under bending and under combined tension and bending. The proposed method is based on the reference stress approach, where the dependence of elastic and plastic influence functions of J on the cylinder/crack geometry, the off-centred angle and strain hardening is minimised through the use of a proper normalising load. Based on published limited FE results for off-centred, circumferential through-wall cracks under bending, such normalising load is found, based on which the reference stress based J estimates are proposed for more general cases, such as for a different cylinder geometry and for combined loading. Comparison of the estimated J with extensive FE J results shows overall good agreements for different crack/cylinder geometries and for combined tension and bending, which provides sufficient confidence in the use of the proposed method to fracture mechanics analyses of off-centred circumferential cracks. Furthermore, the proposed method is simple to use, giving significant merits in practice.

Keywords

Elastic-Plastic Fracture Mechanics;J-integral;Off-Centred Circumferential Crack;Reference Stress Method

References

  1. Kim, Y.J., Huh, N.S. and Kim, Y.J., 2002, 'Quantification of Pressure-Induced Hoop Stress Effect on Fracture Analysis of Circumferential Through-Wall Cracked Pipes,' Engineering Fracture Mechanics, Vol. 69, No. 11, pp. 1249-1267 https://doi.org/10.1016/S0013-7944(01)00132-1
  2. 2001, 'ABAQUS User's manual,' Hibbitt, Karlson & Sorensen, Inc.
  3. Kumar, V. and German, M.D., 1988, 'Elastic-Plastic Fracture Analysis of Through- Wall and Surface Flaws in Cylinders,' EPRI Report, NP-5596
  4. Miller, A.G, 1988, 'Review of Limit Loads of Structures Containing Defects,' International Journal of Pressure Vessels and Piping, Vol. 32, pp. 191-327 https://doi.org/10.1016/0308-0161(88)90073-7
  5. 2001, 'R6: Assessment of the Integrity of Structures Containing Defects,' Revision 4, British Energy Generation Ltd.
  6. Ainsworth, R.A., 1984, 'The Assessment of Defects in Structures of Strain Hardening Materials,' Engineering Fracture Mechanics, Vol. 19, pp. 633-642 https://doi.org/10.1016/0013-7944(84)90096-1
  7. Kim, Y.J. and Budden, P.J., 2002, 'Reference Stress Approximations for J and COD of Circumferential Through-Wall Cracked Pipes,' International Journal of Fracture, Vol. 116, pp. 195-218 https://doi.org/10.1023/A:1020158730727
  8. Hub, N.S., Kim, Y.J. and Kim, Y.J., 2001, 'New Engineering Approach for Estimating Crack Opening Displacement for Complex Cracked Pipes,' Transaction of the KSME (A), Vol. 25, No.8, pp. 1235-1241
  9. Kim, .YJ., Hub, N.S. and Kim, Y.J., 2002, 'Reference Stress Based Elastic-Plastic Fracture Analysis for Circumferential Through-Wall Cracked Pipes under Combined Tension and Bending,' Engineering Fracture Mechanics, Vol. 69, No. 3, pp. 367-388 https://doi.org/10.1016/S0013-7944(01)00074-1
  10. Firmature, F. and Rahman, S., 2000, 'Elastic-Plastic Analysis of Off-Center Cracks in Cylindrical Structures,' Engineering Fracture Mechanics, Vol. 66, pp. 15-39 https://doi.org/10.1016/S0013-7944(99)00135-6
  11. Kim, Y.J., Huh, N.S. and Kim, Y.J., 2001, 'New Engineering Estimation Method of J-Integral and COD for Circumferential Through-Wall Cracked Pipes,' Transaction of the KSME (A), Vol. 25, No.3, pp. 548-553
  12. Rahman, S., Brust, F., Ghadiali, N. and Wilkowski, G, 1998, 'Crack-Opening-Area Analyses for Circumferential Through-Wall Cracks in Pipes-Part II: Model Validation,' International Journal of Pressure Vessels and Piping, Vol. 75, pp. 375-396 https://doi.org/10.1016/S0308-0161(97)00082-3
  13. Rahman, S., Brust, F., Ghadiali, N. and Wilkowski, G., 1998, 'Crack-Opening-Area Analyses for Circumferential Through-Wall Cracks in Pipes-Part III: Off-Center Crack, Restraint of Bending, Thickness Transition and Weld Residual Stresses,' International Journal of Pressure Vessels and Piping, Vol. 75, pp. 397-415 https://doi.org/10.1016/S0308-0161(97)00083-5
  14. Rahman, S., Ghadiali, N., Wilkowski, G and Bonora, N., 1997, 'Effects of Off-Centred Crack and Restraint of Induced Bending Due to Pressure on the Crack Opening Area Analysis of Pipes,' Nuclear Engineering Design, Vol. 167, pp. 55-67 https://doi.org/10.1016/S0029-5493(96)01289-7
  15. NUREG 1061, 1984, 'Evaluation of Potential for Pipe Break,' Vol. 3, USNRC
  16. Rahman, S., Brust, F., Ghadiali, N. and Wilkowski, G, 1998, 'Crack-Opening-Area Analyses for Circumferential Through-Wall Cracks in Pipes-Part I: Analytical Models,' International Journal of Pressure Vessels and Piping, Vol. 75, pp. 357-373 https://doi.org/10.1016/S0308-0161(97)00081-1