All stress-strain input should be in terms of true stress and true (or logarithmic) strain and result in all output as also true stress and true strain. For small-strain regions of response, true stress-strain and engineering stress-strain are approximately equal. If your stress-strain data is in the form of engineering stress and engineering strain you can convert:
strain from engineering strain to logarithmic strain using:
engineering stress to true stress using:
Note: This stress conversion is only valid for incompressible materials.
The following Plasticity models are discussed in this section:
- 11.7.1. Bilinear Isotropic Hardening
- 11.7.2. Multilinear Isotropic Hardening
- 11.7.3. Bilinear Kinematic Hardening
- 11.7.4. Multilinear Kinematic Hardening
- 11.7.5. Johnson-Cook Strength
- 11.7.6. Cowper-Symonds Strength
- 11.7.7. Steinberg-Guinan Strength
- 11.7.8. Zerilli-Armstrong Strength
- 11.7.9. Orthotropic Strength Model