hi Mr Sampat, thanks for the reply. So i've tried your loads of my model but i've always the same problem. i find 0.023mm in total deformation.

In my inital model i've also applied 2 displacement on flat faces but i've allowed 1 displacement on each face ( eg : Ux=0 Uy=0 Uz=free) Screenshot :

My analysis is about thermal expansion of a roll reprenseted by a quart in Ansys for simplifying the problem. I think frictionless support is not the most adapted to represent the problem. I'll retry a new analysis and i'll update you  

Best regards