Abstract
An integral regularization method was applied to the
Gurson-Tvergaard-Needleman (GTN) damage model to address the plastic
deformation localization at the crack tip. The parameters for the
constitutive model were calibrated with an evolutionary algorithm. The
model was applied to predict ductile fracture of a tensile specimen,
allowing mesh convergence and geometry independence. Fatigue crack
growth was predicted through a node release strategy, obtaining a very
good approximation to the experimental results in the upper part of the
Paris Regime. Mesh independence was verified for medium/high Δ K
levels, but near the threshold regime no mesh independence was obtained
and da/dN was overestimated. The characteristic length for the
non-local model was defined as the reverse plastic zone size, which
indicates that this should be the fatigue process zone. Finally, at the
accelerated regime, final fracture loci predictions agree with the
experimental results, but mesh independence was barely achieved.