Hi everyone!

I'm doing a modal analisys on two concentrical cylinders.

All I want to schematize is the concentrical position between the tubes. For this reason, I should place a CONN element between the green and the gray parts (see the red rectangle in the figure below).

I wanted to mantain the concentricity between parts also in my results (or at least I don't want the compenetration between elements - in a modal analysis I cannot use contacts), how would you schematize the CONN behavior?

Doing some test, placing "Kinematic" in "Coupling type" is working but I prefer using "Distributing" in order not to add additional stiffness to my model. 

Also, the "stop" behavior seems not working (defining the range, the condition is not observed). What am I missing?

Thanks