FINITE-ELEMENT SIMULATIONS OF DUCTILE RUPTURE IN A CONSTRAINED METAL FOIL

A numerical study of the ductile rupture in a metal foil constrained b etween two stiff ceramic blocks is performed. The finite element analy sis is carried out under the conditions of mode I, plane strain, small -scale yielding. The rate-independent version of the Gurson model that accounts for the ductile failure mechanisms of microvoid nucleation, growth and coalescence is employed to represent the behavior of the me tal foil. Different distributions of void nucleating sites in the meta l foil are considered for triggering the initiation of discrete voids. The results clearly show that far-field triaxiality-induced cavitatio n is the dominant failure mode when the spacing of the void nucleating sites is large. On the contrary, void coalescence near the notch tip is found to be the operative failure mechanism when closely spaced voi d nucleating sites are considered.