Great mechanical expansions

Hi everybody,

I am trying to simulate with Structural Mechanics Module in 2D axial simmetry (COMSOL 3.5) the following situation:

I would like to predict the stresses of a material under the loads given by an expansion of a second material inserted into the first one. I have tried to modify gradually the strains of the internal material imposing a time-variant initial strain and remeshing the geometry (imposing a stop condition) step by step thanks to the moving mesh ALE module. I would like to reach a great expansion (eps = 1000) but my simulation stops at eps = 1: I encounter in inverted mesh elements.

My question is: is it possible to simulate this situation? Have you any suggestions to obtain such a great expansion?
I attached the file here to better understand the geometry!

Thanks,

Emanuele