Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Analysis of Cleavage Fracture Toughness of PCVN Specimens Based on a Scaling Model

PCVN 시편 파괴인성의 균열 깊이 영향에 대한 Scaling 모델 해석

  • Published : 2009.04.01
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Abstract

Standard procedures for a fracture toughness testing require very severe restrictions for the specimen geometry to eliminate a size effect on the measured properties. Therefore, the used standard fracture toughness data results in the integrity assessment being irrationally conservative. However, a realistic fracture in general structures, such as in nuclear power plants, may develop under the low constraint condition of a large scale yielding with a shallow surface crack. In this paper, cleavage fracture toughness tests have been made on side-grooved PCVN (precracked charpy V-notch) type specimens (10 by 10 by 55 mm) with various crack depths. The constraint effects on the crack depth ratios were evaluated quantitatively by the developed scaling method using the 3-D finite element method. After the fracture toughness correction from scaling model, the statistical size effects were also corrected according to the standard ASTM E 1921 procedure. The results were evaluated through a comparison with the $T_0$ of the standard CT specimen. The corrected $T_0$ for all of the PCVN specimens showed a good agreement to within $5.4^{\circ}C$ regardless of the crack depth, while the averaged PCVN $T_0$ was $13.4^{\circ}C$ higher than the real CT test results.

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References

  1. Wallin, K., 2001, 'Quantifying Tstress Controlled Constraint by the Master curve Transition Temperature T0,' Eng. Fra. Mechanics, Vol. 68, pp. 303-328 https://doi.org/10.1016/S0013-7944(00)00067-9
  2. O'Dowd, N. P., Shih, C. F., and Dodds, Jr., R. H., 1995, 'The Role of Geometry and Crack Growth on Constraint and Implications for Ductile/Brittle Fracture,' ASTM, Philadelphia
  3. Nevalainen, M., and Dodds, Jr., R. H., 1995, 'Numerical Investigation of 3-D Constraint Effect on Brittle Fracture in SE(B) and C(T) Specimens,' Int. J. of Fra., Vol. 74, pp. 131-161 https://doi.org/10.1007/BF00036262
  4. E1921-05, 2005, 'Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range,' ASTM, Philadelphia
  5. Sumpter, J.D.G., 1987, 'Jc Determination for Shallow Notch Welded Bend Specimens,' Fat. & Fra. Of Eng. Mat & Struc., Vol. 10, pp. 479-493 https://doi.org/10.1111/j.1460-2695.1987.tb00498.x
  6. Lee, B. S., Yang, W. J., Huh, M. Y., Kim, J. H. and Hong, J. H., 2000, 'Evaluation of the Fracture Toughness Transition Characteristics of RPV Steels Based on the ASTM Master Curve Method Using Small Specimens,' Trans. of the KSME(A), Vol. 24, No.2, pp. 303-310
  7. Ritchie, R. O., Knott, J. F. and Rice, J. R., 1973, 'On the Relationship Between Critical Tensile Stress and Fracture Toughness in Mild Steel,' J. of the Mech. and Phys. of Sol., Vol. 21, pp 935-410 https://doi.org/10.1016/0022-5096(73)90008-2
  8. S. Howard, 2003, Thesis, 'Size effects on cleavage Fracture Toughness, Master Curve Test(constraint-effect model),' UCSB
  9. Odette, G. R. and He, M. Y., 2000, 'A Cleavage Toughness Master Curve Model,' J. of Nuclear Materials, Vol. 283-287, pp. 120-127 https://doi.org/10.1016/S0022-3115(00)00334-2