R. Narasimhan et S. Basu, Numerical simulations of fracture initiation in ductile solids under mode I, dynamic loading, B MATER SCI, 22(5), 1999, pp. 891-900
In this paper, an overview of some recent computational studies by the auth
ors on ductile crack initiation under mode I, dynamic loading is presented.
In these studies, a large deformation finite element procedure is employed
along with the viscoplastic version of the Gurson constitutive model that
accounts for the micro-mechanical processes of void nucleation, growth and
coalescence. A three-point bend fracture specimen subjected to impact, and
a single edge notched specimen loaded by a tensile stress pulse are analyse
d. Several loading rates are simulated by varying the impact speed or the r
ise time and magnitude of the stress pulse. A simple model involving a semi
-circular notch with a pre-nucleated circular hole situated ahead of it is
considered. The growth of the hole and its interaction with the notch tip,
which leads to plastic strain and porosity localization in the ligament con
necting them, is simulated. The role of strain-rate dependence on ductile c
rack initiation at high loading rates, and the specimen geometry effect on
the variation of dynamic fracture toughness with loading rate are Investiga
ted.