NUMERICAL RESULTS FOR TRANSFORMATION TOUGHENING IN CERAMICS

Finite element analysis was used to study the fracture toughening of a ceramic by a stress-induced dilatant transformation of second phase particles. The finite element method was based on a continuum theory which modelled the composite as a subcritical material. Transient crack growth was simulated in the finite element mesh by a nodal release technique. The crack's remote tensile opening load was adjusted to maintain the near-tip energy release rate at the level necessary for crack advance. The transformation zone surrounding the crack developed as the crack propagated through the composite. Resistance curves were computed from the analysis; the results confirm that during crack advance maximum toughness is achieved before steady state is reached. Diagrams of each transformation zone and R-curve are provided to expedite comparison with experimental data. © 1990.