A Fracture Model Applied to the Ductile/Brittle Regime

Abstract

The fracture resistance of ferritic steels in the ductile/brittle transition regime is controlled by the competition between ductile tearing and cleavage fracture. Under typical conditions, a crack initiates and grows by ductile tearing but ultimate failure occurs by catastrophic cleavage fracture. In this paper the tearing process is simulated using void-containing cell elements embedded within a conventional elastic-plastic continuum. Weakest link statistics is incorporated into the cell element model and this new model is employed to predict the onset of unstable cleavage fracture. Load-displacement behavior, ductile tearing resistance and transition to cleavage fracture are investigated for three different test geometries. The model predicts trends in ductile/brittle transition that are consistent with experimental data.