DOI QR코드

DOI QR Code

Failure Mode and Fracture Behavior Evaluation of Pipes with Local Wall Thinning Subjected to Bending Load

감육배관의 굽힘하중에 의한 손상모드와 파괴거동 평가

  • Published : 2003.01.01

Abstract

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear Power Plant. In Pipes of energy Plants, sometimes, the local wall thinning may result from severe erosion-corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization. crack initiation/growth after ovalization, local buckling and crack initiation/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated.

Keywords

Local Wall Thinning;Failure Mode;Pipe;Bending Load;Fracture Behavior;Allowable Limit

References

  1. Kim, J. W., Park, C. Y. and Kim, B. N., 2001, ' Evaluation of Local Allowable Wall Thickness of Thinned Pipe Subjected to Internal Pressure and Bending Moment,' Transactions of the KSME A, Vol. 25, No.1, pp. 81-88
  2. Kanninen, M. F., Zahoor, A., Wilkowski, G., Abousayed, J., Marschall, C., Broek, D., Sampath, S., Rhee, H. and Ahmad, J., 1982, ' Instsbility Predictions for Circumferentially Cracked Type-304 Stainless Pipes under Dynamic Loading,' EPRI NP-2347, Vols. 1 and 2, EPRI, Palo Alto
  3. Okamura, K., 1970,' Expansion on Statically Indeterminate Problem of Fracture Mechanics,' JHPI, Vol. 8, No. 2, p. 19-24
  4. Liu, S. P. and Ando, K., 1996,' Ultimate Strength and Plastic Collapse Behavior of Statically Indeterminate Pipes with Crack and Compliances,' JSME, Vol. 62, Vo. 597, pp. 48-55
  5. Horen, M. R., 1979,' Plastic Theory of Structures, 2nd Edition,' Pergamon Press, Oxford
  6. Liu, S. P. and Ando, K., 2000,' Leakbefore-break and plastic collapse behavior of statically with circumferential crack,' Nuclear Engineering and Design 195, pp. 261-270 https://doi.org/10.1016/S0029-5493(99)00211-3
  7. ASME Boiler and Pressure Vessel Code Sec. III, 1986
  8. Ahn, S. H., Ando, K., Isiwata, M. and Hasegawa, K., 1998, ' Plastic Collapse Behavior of Pipes with Local Wall Thinning Subjected to Bending Load Allowable Limit,' JHPI, Vol. 36, No.4, pp. 225-234
  9. Virginia Electric and Power Co., 1987,' Surry Unit 2 Reactor Trip and Feedwater Pipe Failure Report.'
  10. Shim, S. H., Song, J. S., Yoon, K. B., Hwang, K. M., Jin, T. E., Lee, S. H. and Kim, W. S., 2000, ' Application of CHECWORKS Code for Metal Loss in the Secondary Piping Systems Wolsung Unit 1,' Proceeding of the Pressure Equipment Tech. Conference 2000, pp. 59-64
  11. Deardorff, A. F. and Bush, S. H., 1990, 'Development of ASME Section Criteria for Erosion-Corrosion Thinning of Carbon Steel Piping,' ASME PVP, PVP-Vol-186, NDE-VoI.7, pp.71-75
  12. Mathonet, J. F., Cherasse, J. M., Leblois, C. L. and Guyette, M. A., 1995,' Belgian Methodology for Evaluation of Erosion Corrosion phenomena in Unit 1; 2; 3 & 4 of the DOEL Nuclear Power Plant(NPP),' ASME PVP, PVP-Vol-303, pp. 393-399
  13. ASME Boiler and Pressure Vessel Code Sec. X I, 1998
  14. Miyazaki, K., Kanno, S., Ishiwata, M., Hasegawa, K., Ahn, S. H. and Ando, K., 1999, 'Fracture Behavior of Carbon Steel pipe with Local Wall Thinning Subjected to Bending Load,' Nuclear Engineering and Design 191, pp. 195-204 https://doi.org/10.1016/S0029-5493(99)00141-7
  15. Kim, J. W., Park, C. Y. and Kim, B. N., 1999, ' Effects of Axial Extent of Thinned Area on the Allowable Wall Thickness in Thinned Pipe,' Proceedings of the KSME 1999 Fall Annual Meeting A, pp. 597-602