Thanks a lot. I don't have any gap but if I want to consider friction coefficient should I specify Cnodes again?

And also, how can I model a rest support which moves laterally but not as much as the pipe. for example the the structure which the shoe is on moves 10" (+Z) but the pipe moves 15"(+Z) due to the movement of another platform. When there is a friction coefficient it affects the results. doesn't it?

Thank you