Abaqus sensitvity for force calculation in compression test

Dear all,
 

 I am trying to simulate a very simple compression test in abaqus/standard with axisymmetric symmetry. 
 

 Not the probolem I have is, the force calculation is not sensitvie to the yield curve I give. For example, I give a linearly increasing yield curve with slope of 100, and then I give a yield curve with slope of 100.1 I get the same force in the first few increments during the calculation. I tried using double precision and also fully integrated elements.
 

 Could I do anything else to make abaqus sensitive for small changes in yield curve?
 

 Thanks,
 Aditya.