Abstract
Fracture initiation in ductile metal plates occurs due to substantial tunneling of the crack in the interior of the specimen followed by final failure of side ligaments by shear lip formation. The tunneled region is characterized by a flat, fibrous fracture surface. This phenomenon is clearly exhibited in a recent experimental investigation [8] performed on pre-notched plates of a ductile heat treatment of 4340 carbon steel. Experimental evidence obtained in [8] suggests that tunneling begins at an average value of J which is significantly lower than the J value at which gross initiation is observed on the free surface. In the present work, fracture initiation in the 4340 steel specimens used in [8] is analyzed by performing a 3-dimensional numerical simulation. A damage accumulation model that accounts for the ductile failure mechanisms of void nucleation, growth, and void coalescence is employed. Results indicate that incipient Cmaterial failure at the center-plane of the 3-dimensional specimen is predicted quite accurately by this computation. Also, good agreement between results obtained at the center-plane of the 3-dimensional specimen and a plane strain analysis, suggests that a local definition of J can be used to characterize fracture initiation in the center-plane of the specimen. Finally, radial and thickness variations of the stress and porosity fields are examined with view of understanding the subsequent propagation of the failure zone.
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References
T.B. Cox and J.R. Low, Metallurgical Transactions 5 (1974) 1457–1470.
F.A. McClintock, Journal of Applied Mechanics 35 (1968) 363–371.
J.R. Rice and D.M. Tracey, Journal of Mechanics and Physics of Solids 17 (1969) 201–217.
H.C. Rogers, Transactions of Metallurgical Society AIME 218 (1960) 498–506.
V. Tvergaard, International Journal of Fracture 17 (1981) 389–407.
S.H. Goods and L.M. Brown, Acta Metallurgica 27 (1979) 1–15.
L.M. Brown and J.D. Embury, in The Microstructure and Design of Alloys, Proceedings of the 3rd International Conference on the Strength of Metals and Alloys, Cambridge, England (1973).
A.T. Zehnder and A.J. Rosakis, Journal of Applied Mechanics, to appear.
R. Narasimhan and A.J. Rosakis, Journal of Applied Mechanics, to appear.
A.T. Zehnder, A.J. Rosakis and S. Krishnaswamy, International Journal of Fracture 43 (1990) 209–230.
A.L. Gurson, Transactions of the American Society of Mechanical Engineers, Series H, Journal of Engineering Materials and Technology 99 (1977) 2–15.
V. Tvergaard and A. Needleman, Acta Metallurgica 32 (1984) 157–169.
S. Aoki, K. Kishimoto, A. Takeya and M. Sakata, International Journal of Fracture 24 (1984) 267–278.
N. Aravas and R.M. McMeeking, International Journal of Fracture 29 (1985) 21–38.
A. Jagota, C.Y. Hui and P.R. Dawson, International Journal of Fracture 33 (1987) 111–124.
R. Becker, A. Needleman, O. Suresh, V. Tvergaard and A.K. Vasudevan, Acta Metallurgica 37 (1989) 99–120.
R. Becker, A. Needleman, O. Richmond and V. Tvergaard, Journal of Mechanics and Physics of Solids 36 (1988) 317–351.
H. Andersson, Journal of Mechanics and Physics of Solids 25 (1977) 217–233.
C.C. Chu and A. Needleman, Transactions of American Society of Mechanical Engineers, Series H, Journal of Engineering Materials and Technology 102 (1980) 249–256.
C.A. Berg, in Inelastic Behavior of Solids, M.F. Kanninen, W.F. Adler, A.R. Rosenfield and R.I. Jaffee (eds.), McGraw-Hill (1970) 171–209.
R. Narasimhan and A.J. Rosakis, Journal of Mechanics and Physics of Solids 36 (1988) 77–117.
H. Mathies and G. Strang, International Journal for Numerical Methods in Engineering 14 (1979) 1613–1626.
V. Tvergaard, Journal of Mechanics and Physics of Solids 30 (1982) 399–425.
B. Budiansky and J.R. Rice, Journal of Applied Mechanics 40 (1973) 201–203.
T. Nakamura, C.F. Shih and L.B. Freund, ASTM STP 995, to appear.
F.Z. Li, C.F. Shih and A. Needleman, Engineering Fracture Mechanics 21 (1985) 405–421.
C.F. Shih, B. Moran and T. Nakamura, International Journal of Fracture 30 (1986) 79–102.
J.W. Hutchnson, Journal of Mechanics and Physics of Solids 16 (1986) 337–347.
J.R. Rice and G.F. Rosengren, Journal of Mechanics and Physics of Solids 16 (1968) 1–12.
C.F. Shih, Journal of Mechanics and Physics of Solids 29 (1981) 305–326.
R. Narasimhan, A.J. Rosakis and J.F. Hall, Journal of Applied Mechanics 54 (1987) 838–845.
J.R. Rice, in Mechanics and Mechanisms of Crack Growth, M.J. May, (ed.), British Steel Corp. Physical Metallurgy Centre Publication, Sheffield, England (1975) 14–39.
B. Moran, R.J. Asaro and C.F. Shih, Metallurgical Transactions A 22A (1991) 161–170.
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Narasimhan, R., Rosakis, A.J. & Moran, B. A three-dimensional numerical investigation of fracture initiation by ductile failure mechanisms in a 4340 steel. Int J Fract 56, 1–24 (1992). https://doi.org/10.1007/BF00042428
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DOI: https://doi.org/10.1007/BF00042428