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Effect of Wall Thinning on the Failure of Pipes Subjected to Bending Load

굽힘하중을 받는 배관의 파손에 미치는 감육의 영향

  • 안석환 (부경대학교 기계공학부) ;
  • 남기우 (부경대학교 신소재공학부)
  • Published : 2005.04.01

Abstract

Effects of circumferentially local wall thinning on the fracture behavior of pipes were investigated by monotonic four-point bending. Local wall thinning was machined on the pipes in order to simulate erosion/corrosion metal loss. The configurations of the eroded area included an eroded ratio of d/t= 0.2, 0.5, 0.6, and 0.8, and an eroded length of ${\ell}\;=10mm,$ 25mm, and 120mm. Fracture type could be classified into ovalization, local buckling, and crack initiation depending on the eroded length and eroded ratio. Three-dimensional elasto-plastic analyses were also carried out using the finite element method, which is able to accurately simulate fracture behaviors excepting failure due to cracking. It was possible to predict the crack initiation point by estimating true fracture ductility under multi-axial stress conditions at the center of the thinned area.

Keywords

Bending Load;Wall Thinning;Finite Element Analysis;Pipe;True Fracture Ductility;Equivalent Strain

References

  1. Ahn, S. H., Nam, K. W. Yoo, Y. S., Ando, K., Ji, S. H., Ishiwata, K. and Hasegawa, K., 2002, 'Fracture Behavior of Straight Pipe and Elbow with Local Wall Thinning,' Nuclear Engineering and Design, Vol. 211, pp. 91-103 https://doi.org/10.1016/S0029-5493(01)00447-2
  2. 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, Vol. 191, pp.195-204 https://doi.org/10.1016/S0029-5493(99)00141-7
  3. Ahn, S. H., Nam, K. W., Kim, S. J., Kim, J. H., Kim, H. S. and Do, J. Y., 2003, 'Failure Mode and Fracture Behavior Evaluation of Pipes with Local Wall Thinning Subjected to Bending Load,' Trans. of the KSME(A), Vol. 27, No. 1, pp. 8-17 https://doi.org/10.3795/KSME-A.2003.27.1.008
  4. Nam, K. W. and Ahn, S. H., 2004, 'Fracture Behaviors and Acoustic Emission Characteristics of Pipes with Local Wall Thinning,' Key Engineering Materials, Vol. 270-273, pp. 461-465 https://doi.org/10.4028/www.scientific.net/KEM.270-273.461
  5. Kim, J. W., Nam, K. W. and Ahn, S. H., 2004, 'Nondestructive Evaluation of Pipes with Local Wall Thinning by Wavelet Analysis of Elastic Wave,' Key Engineering Materials, Vol. 270-273, pp. 954-958 https://doi.org/10.4028/www.scientific.net/KEM.270-273.954
  6. Kim, J. W and Park, C. Y., 'An Evaluation of Failure Behavior of Pipe with Local Wall Thinning by Pipe Experiment,' Trans. of the KSME(A), Vol. 26, No. 4, pp. 731-738 https://doi.org/10.3795/KSME-A.2002.26.4.731
  7. Son, B. G., Kim, Y. J. and Kim, Y. J., 2004, 'Finite Element Based Stress Concentration Factors for Pipes with Local Wall Thinning,' Trans. of the KSME(A), Vol. 28, No. 7, pp. 1014-1020 https://doi.org/10.3795/KSME-A.2004.28.7.1014
  8. Miyazaki, K., Nebu, A., Kanno, S., Ishiwata, M. and Hasegawa, K., 2002, 'Study on Fracture Criterion for cabon steel pipes with Local Wall Thinning,' J. of High pressure Institute of Japan, Vol. 40, No. 2, pp. 62-72
  9. Weiss, V., 1972, Proceeding 1st Int. Conf. on Mechanical Behavior of Materials, pp. 159
  10. Ramberg, W. and Osgood, W. R., 1943, 'Description of Stress-Strain Curves by Three,' NACA Technical Note, No. 902

Cited by

  1. Leak-Before-Break Behavior and Crack Opening Displacement in Piping Under Bending Load vol.34, pp.6, 2010, https://doi.org/10.3795/KSME-A.2010.34.6.725