Hello JStorm,
thanks a lot for your very quick reply! First of all, I am glad to hear that the translation dofs could be fixed.
It is hard to explain what I really need, but generally I need all the deformation vectors.
To fixed the translation of RVE is more important than the fixed rotation. In may case the small rotation is not a problem, even it exist.
May I ask further whether it is necessary to fixe the rotational ones?
If I calculate the six deformations G11, G22, G33, G12+G21, G23+G32, G13+G31, the last three have rigid body rotations.
So maybe it should not be fixed, for the situation if only one model is used.
My question now is, maybe there is no free rotation at all, because of PBC? Can you please give some hints? Thank you so much!!