An extended model for void growth and coalescence

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.