1 likeNode to Node contact is not available as a pure 'Contact'. But you can achieve this using CGAP/PGAP. I believe there are a few tutorials and the documentation is clear enough. But essentially you create a gap element, and assign a PGAP property defining u0 (gap aperture) and K0/K1 stiffness for open/close gap. In this case you need to perform a NLSTAT loadstep.