I am trying to simulate the action of a ram assembly - outer ram housing which houses a hydraulic cylinder, which controls an inner ram (inner ram slides within the outer housing). There are 8 bearing plates between the inner & the outer housing. I have no penetration contacts between the bearings & the inner ram and the bearings are bolted to the outer housing.

My question is - How do I simulate the rigidness of the hydraulic cylinder without actually adding the cylinder in my model?

I created two spilt surfaces on the outer and the inner ram and added a fixture using the 'Reference geometry - On model faces' and made that a no translation along the y axis (no up & down motion). Is that correct?

Thank you