A ductile–brittle fracture model for material ductile damage in plastic deformation based on microvoid growth

The fracture of ductile solids has frequently been observed to result from the large growth and coalescence of microscopic voids, a process enhanced by the superposition of hydrostatic tensile stresses on a plastic deformation field. The ductile growth of voids is treated here as a problem in continuum plasticity. In this paper, a ductile–brittle fracture criterion derived from a microvoid mechanical model is proposed for microdamage and fracture of metallic material under large elastic–plastic deformation and has been proved to be effective in the analysis of metal forming process. Using this criterion, the analyses of microdamage and ductile–brittle fracture for tensile specimens in complex stress-states have been carried out. The results from these analyses on damage development and fracture are in good agreement with the experimental ones, and from microview point are reasonable for cracked specimens.