Effects of grain boundary heterogeneities on creep fracture studied by rate-dependent cohesive model
Journal
Engineering Fracture Mechanics
Journal Volume
93
Pages
48-64
Date Issued
2012
Author(s)
Abstract
To simulate creep fracture of ceramics at high temperatures, we have developed a user-defined element (UEL) subroutine and a user-defined material properties (UMAT) subroutine to analyze the rate-dependent cohesive behavior of the grain boundary and the creep deformation of the grain, respectively, and implemented them in ABAQUS. The model presented here accounts for grain boundary sliding, nucleation of grain boundary cavities, their growth by diffusion and creep, and link up of microcracks to form macrocracks. Numerical examples demonstrate that the rate-dependent cohesive element has a better numerical stability than the existing work and the entire cavity growth process can be simulated. Also, in the presence of grain boundary heterogeneities, stress distribution becomes localized which, in turn, induces localized grain boundary cavitation and promotes creep fracture. ? 2012 Elsevier Ltd.
Subjects
Cavity nucleation/growth
Creep fracture
Grain boundary sliding
Heterogeneities
Rate-dependent cohesive model
Type
journal article