2014:28 Numerical simulation of ductile crack growth in residual stress fields

The study has shown on the capability of the cell model in capturing the effects on ductile tearing from limited pre-load levels and a residual stress field.
Some of the conclusions are as follows:

  • No distinctive influence on the material fracture toughness is observed from pre-loading (work hardening), both tensile and compressive, at room temperature of 1.5 or 3 % total strain.
  • The cell model gives good predictions of the experimentally generated JR-curves for pre-load levels up to 3% in compression and tension. As for the experimental results, no significant effect from the pre-load on the fracture resistance is seen for pre-load levels up to 3%.
  • The predicted results overestimate the material fracture toughness for pre-load levels of 6%. The seen effect from the experimental results at a pre-load level of 6% is much larger than the predicted effect both for compression and tension. The current cell model fails therefore to accurately capture the large effects seen at higher levels of pre-load.

The results show the capability of the so-called Gurson model to capture the increased fracture toughness compared to the standard specimen which is due to constraint effects.