1. Polycrystal plasticity – trial problems and first steps August 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. 1-Grain, 27-Element Test Problem
Single Grain Model
- 5% applied compressive strain z 1 3 2 8 7 9 5 6 4 12 10 11 y x

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

5. 1-Grain, 27-Element Test Problemz
RPI UMAT 2 1 3 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