A finite element study of the effects of material characteristics and crack tipconstraint on dynamic ductile fracture initiation

Abstract

In this work, 2-D (plane strain) finiteelement analyses of a ductile three-point bend fracture specimen subjected to Mode I, dynamic (impact-like) loading are conducted. The initiation of a hole by debonding around a large inclusion and its interaction with the notch tip is simulated. The background material isrepresented by the Gurson constitutive model and micro-void nucleation at uniformly distributedsmall size particles is also taken into account. The development of ductile failure due to theaccumulation of micro-void damage in the ligament between the notch-tip and the inclusion isstudied. The influence of impact speed, rate dependence and thermal softening (due to adiabaticheating) of the matrix material on dynamic, ductile fracture initiation are quantitatively assessed. Also, the effects of the bond strength of the matrix-inclusion interface, and, crack tip constraint are examined.