Void growth and interaction in crystalline materials

An inelastic rate-dependent crystalline constitutive formulation and specia lized computational schemes have been developed and used to obtain a detail ed understanding of the interrelated physical mechanisms that can result in ductile material failure in rate-dependent porous crystalline materials su bjected to finite inelastic deformations. The effects of void growth and in teraction and specimen necking on material failure have been investigated f or a single material cell, with a discrete cluster of four voids, where geo metrical parameters have been varied to result in seven unique periodic and random void arrangements. The interrelated effects of void distribution an d geometry, strain hardening, geometrical softening, localized plastic stra ins and slip-rates, and hydrostatic stresses on failure paths and ligament damage in face centered cubic (f.c.c.) crystalline materials have been stud ied. Results from this study are consistent with experimental observations that ductile failure can occur either due to void growth parallel to the st ress axis, which results in void coalescence normal to the stress axis, or void interaction along bands, which are characterized by intense shear-stra in localization and that intersect the free surface at regions of extensive specimen necking. (C) 2001 Published by Elsevier Science Ltd.