Polycrystal plasticity – trial problems and first steps August 2007 monthly meeting

1. Polycrystal plasticity – trial problems and first stepsAugust 2007 monthly meeting

2. Polycrystal Plasticity UMAT Refs Kysar implements the Bassani & Wu hardening model: Huang – Single Crystal Plasticity UMAT RPI implements both the Voce-Kocks and RPI hardening model: Voce-Kocks – FCC Strain Hardening Maniatty – Elasto-viscoplastic Model

3. 11 7 1 2 4 10 9 6 8 5 12 3 1-Grain, 27-Element Test Problem Single Grain Model - 5% applied compressive strain z y x

4. z 1 2 y 3 x 1-Grain, 27-Element Test Problem Kysar UMAT

5. 1 2 3 1-Grain, 27-Element Test Problem z RPI UMAT y x

6. Kysar-RPI comparison • Although the hardening models are not the same, many of the material input parameters are the same (e.g. RPI updates the saturation stress, where it is constant in Kysar). • We took Antoinette’s material parameters and put them into Kysar’s .inp so we could observe differences in the material models.

7. Kysar-RPI comparison

8. Next Steps: - “Validation” models- Realization models Automation of model generation using Python/ABAQUS Demo zip file