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.