Elasto-plastic model in polycrystal simulation

[adp0014]

Hi everyone!
I want to simulate a polycrystalline structure (with Voronoi tesselation) in ABAQUS but I am a little bit confused with the elasto-plastic model that I should use. Since each grain has a different orientation, elastic and plastic behaviour will be anisotropic within each grain. So, is it not possible to avoid the use of Crystal Plasticity (CP-FEM)? I have read some papers using classical plasticity in which all grains are modelled with the same E (Young Modulus) and yield strenght. I guess that they are neglecting anisotropy, is that correct? Other option to model anistotropy is to assign an elastic stiffness tensor (E11, E22, etc.), and to consider Hill's potential for plasticity.
Could you give me some tips about this topic? How can I use classical plasticity in polycrystals?

Thanks in advance!

 

[Shawn Xavier]

The options with anisotropy or with isotropy is up to your simulation task.

If your structure is going to be treated as an aggregate of single crystals, you'd better assign different orientations to each crystal, meaning that
each of them has its own Schmid factor with regard to an applied stress tensor.

There are other homogenization approaches to model the scenario. For example, Taylor's model posits all grains experience the same strain but still takes into consideration various orientations among crystals.

Classical plasticity is also applicable if you are satisfied with a rather 'phenomenological' description based on macroscopic experiments where anisotropy has already been homogenized due to the large number of crystals.

Shawn