caa a22 4500 469123494 CHVBK 20180323133145.0 cr unu---uuuuu 170328e19920701xx s 000 0 eng 10.1007/BF00042428 doi (NATIONALLICENCE)springer-10.1007/BF00042428 A three-dimensional numerical investigation of fracture initiation by ductile failure mechanisms in a 4340 steel [Elektronische Daten] [R. Narasimhan, A. Rosakis, B. Moran] 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. Kluwer Academic Publishers, 1992 Narasimhan R. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut Rosakis A. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut Moran B. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut International Journal of Fracture Kluwer Academic Publishers 56/1(1992-07-01), 1-24 0376-9429 56:1<1 1992 56 10704 https://doi.org/10.1007/BF00042428 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00042428 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Narasimhan R. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut NATIONALLICENCE 700 1- Rosakis A. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut NATIONALLICENCE 700 1- Moran B. Graduate Aeronautical Laboratories, California Institute of Technology, 91125, Pasadena, California, USA aut NATIONALLICENCE 773 0- International Journal of Fracture Kluwer Academic Publishers 56/1(1992-07-01), 1-24 0376-9429 56:1<1 1992 56 10704 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer