A model for the axisymmetric growth and coalescence of small internal voids
in elastoplastic solids is proposed and assessed using void cell computati
ons. Two contributions existing in the literature have been integrated into
the enhanced model. The first is the model of Gologanu-Leblond-Devaux, ext
ending the Gurson model to void shape effects. The second is the approach o
f Thomason for the onset of void coalescence. Each of these has been extend
ed heuristically to account for strain hardening. In addition, a micromecha
nically-based simple constitutive model for the void coalescence stage is p
roposed to supplement the criterion for the onset of coalescence. The fully
enhanced Gurson model depends on the flow properties of the material and t
he dimensional ratios of the void-cell representative volume element. Pheno
menological parameters such as critical porosities are not employed in the
enhanced model. It incorporates the effect of void shape, relative void spa
cing, strain hardening, and porosity. The effect of the relative void spaci
ng on void coalescence, which has not yet been carefully addressed in the l
iterature. has received special attention. Using cell model computations, a
ccurate predictions through final fracture have been obtained for a wide ra
nge of porosity, void spacing, initial void shape, strain hardening, and st
ress triaxiality. These predictions have been used to assess the enhanced m
odel. (C) 2000 Elsevier Science Ltd. All rights reserved.