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Evaluation of Limit Loads for Circumferentially Cracked Pipes Under Combined Loadings

원주방향 표면 결함이 존재하는 배관에 가해지는 비틀림을 포함한 복합하중에 대한 한계하중식 제시

  • Ryu, Ho-Wan (Dept. of Mechanical Engineering, Korea Univ.) ;
  • Han, Jae-Jun (Dept. of Mechanical Engineering, Korea Univ.) ;
  • Kim, Yun-Jae (Dept. of Mechanical Engineering, Korea Univ.)
  • Received : 2014.02.20
  • Accepted : 2015.03.15
  • Published : 2015.05.01

Abstract

Since the Fukushima nuclear accident, several researchers are extensively studying the effect of torsion on the piping systems In nuclear power plants. Piping installations in power plants with a circumferential crack can be operated under combined loading conditions such as bending and torsion. ASME Code provides flaw evaluations for fully plastic fractures using limit load criteria for the structural integrity of the cracked pipes. According to the recent version of Code, combined loadings are provided only for the membrane and bending. Even though actual operating conditions have torsion loading, the methodology for evaluating torsion load is not established. This paper provides the results of limit load analyses by using finite element models for circumferentially cracked pipes under pure bending, pure torsion, and combined bending and torsion with tension. Theoretical limit load solutions based on net-section fully plastic criteria are suggested and verified with the results of finite element analyses.

Keywords

Limit Loads;Circumferentially Crack;Combined Loadings;Torsion;Finite Element Analysis

Acknowledgement

Supported by : 한국연구재단

References

  1. American Society of Mechanical Engineers, 2011, ASME Boiler and Pressure Vessel Code, Section XI, Non-mandatory Appendix C.
  2. Hill, R., and Siebel, M. P. L., 1951, "On Combined Bending and Twisting of Thin Tubes in the Plastic Range," Phil. Mag., 42, p. 722. https://doi.org/10.1080/14786445108561300
  3. Hodge Jr., P. G. and Panarelli, J., 1963, "Plastic Analysis of Cylindrical Shells Under Pressure, Axial Load and Torque," Proceedings of the Eighth Midwestern Mechanics Conference.
  4. Hoang, P. H., Bezensek, B., Hasegawa, K., and Li, Y., 2010, "Effects of Torsion on Equivalent Bending Moment for Limit Load and EPFM Circumferential Pipe Flaw Evaluations," Proceedings of PVP, Paper No. PVP2010-25283.
  5. Li, Y., Hasegawa, K., Hoang, P. H., and Bezensek, B., 2010, "Prediction Method for Plastic Collapse of Pipes Subjected to Combined Bending and Torsion Moments," ASME PVP2010, Paper No. PVP2010-25101.
  6. Zahoor, A., Wilkowski, G., Abou-Sayed, I., Marschall, C., Broek, D., Sampath, S., Rhee, H., and Ahmad, J., 1982, "Instability Predictions for Circumferentially Cracked Type-304 Stainless Steel Pipes Under Dynamic Loading. Volume 2. Appendixes. Final Report. [BWR]," No. EPRI-NP-2347-Vol.2; Other: ON: DE82903855 United StatesOther: ON: DE82903855Wed Feb 06 20:28:11 EST 2008NTIS, PC A17/MF A01.ERA-07- 043330; INS-82-013208; EDB-82-124473English.
  7. Rahman, S., 1998, "Net-Section-Collapse Analysis of Circumferentially Cracked Cylinders-Part II: Idealized Cracks and Closed-Form Solutions," Engineering Fracture Mechanics, 61(2), pp. 213-230. https://doi.org/10.1016/S0013-7944(98)00061-7
  8. Oh, C. K., Kim, Y. J., Kim, J. S., and Jin, T. E., 2008, "Yield Locus for Circumferential Part-Through Surface Cracked Pipes Under Combined Pressure and Bending," Engineering Fracture Mechanics, 75(8), pp. 2175-2190. https://doi.org/10.1016/j.engfracmech.2007.10.006
  9. Kachanov, L. M., 1971, "Foundations of the Theory of Plasticity," North-Holland Publishing Company.