Hi every one. 

Reading the documentation I often see finite strain, small strain, large displacement, large rotations. I'm a little bit confused about them and I'd would like to clarify all this concepts.

as far as I know, small strain uses infinitesimal strain theory and finite strain uses finite strain theory. But my doubts come when I read about small strain with large rotations for example (I don't reach to visualize and example of that)

My doubts are:

1. Are finite strain the same than large displacements? I think no, but goggling there are some sites where say that are the same. I have always think than large displacements is to take into account the deformed geometry as the current geometry and not the initial configuration (NLGEOM). 
2. is finite strain synonymous of large strain?
3. If I have a model with finite strain formulation elements and I don't activate NLGEOM, is finite strain taken into account?
4. when is more suitable to use small strain formulation instead finite strain formulation?
5. Can I simulate elastic-plastic behaviour with small strain formulation?

Thanks in advance

Abaqus ​​​​​​​