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

In this work, 2-D (plane strain) finite element analyses of a ductile three -point bend fracture specimen subjected to Mode I, dynamic (impact-like) lo ading are conducted. The initiation of a hole by debonding around a large i nclusion and its interaction with the notch tip is simulated. The backgroun d material is represented by the Gurson constitutive model and micro-void n ucleation at uniformly distributed small size particles is also taken into account. The development of ductile failure due to the accumulation of micr o-void damage in the ligament between the notch-tip and the inclusion is st udied. The influence of impact speed, rate dependence and thermal softening (due to adiabatic heating) of the matrix material on dynamic, ductile frac ture initiation are quantitatively assessed. Also, the effects of the bond strength of the matrix-inclusion interface, and, crack tip constraint are e xamined. (C) 1999 Elsevier Science Ltd. Ail rights reserved.