Contact problem at large Indentation

Hello,

I am trying to simulate the case that one hard solid object is being pushed "into" another soft solid object under a large force. The two objects are in contact throughout the process.

It is similar to the example "Cylinder Roller Contact" problem. However, in the example the displacement is very small compared with the size of the object. What I want to see is that the cylinder is pushed almost completely (80%) into the bottom foundation, under the condition that the top is hard (such as diamond) and the bottom is malleable (such as Lithium). In extreme case, the cylinder completely goes into the foundation and leaves its shape.

I have included elastoplastic properties of the materials and the hardening function into the modal. I set Prescribed Displacement for the top cylinder to control its position. It works well at small displacements. However, when I increased the displacement larger and larger (more than 10% of the top cylinder size), the solution cannot converge.

I tried to adjust the contact settings (Penalty Factor, Contact Pressure etc.), but not much success.

Am I missing something?

Thanks for any suggestions.