Discusssion on Crystal plasticity

I know that several groups, e.g., Anand, Meyers, Asaro, Molinari ..., have performed crystal plasticity calcuations with critical slip resistance in each grain depending on grain size to reflect size effect.

If you need a coupling of crystal plasticity with dislocation density, check papers in JMPS by Gao et al. and a group from Europe. Unfortunately, I foget the name of the authors but it was published in JMPS about 2~3 years ago.

For the implementation, check Anand's 1996 paper in JMPS.

I have one question regarding the FEM simulation of rate independent crystal plasticity. Can it be done using the usual displacement based formulation or should the mixed formulation be used (i.e. assumed strain elements)?