Dear Gents, I am new in here so I ask for understanding. Im making a simple simulation of assemble - just 2 parts, one on the other. First made of steel, 2nd of rubber. I put a force on the upper one and when I hit run, the deformation shows only on the upper part. Lower part seems not to move (under the force of upper part) at all. 

However interesting is that when I changed type of rubber - it has moved (so everything was ok). But other type of rubber doesnt put deformation at all. I dont get why. Any thoughts? Thanks in advance!