Defining Contact Between Rod and Base: Contact not being recognized at all

[OverWorked453]

I am trying to run a modal analysis (via the "Frequency Step") for an aluminum, circular bar that can slide in and out of a circular base. In other words, the bar is confined inside a circular base, where the diameter of the base is 0.004 "units" larger than the diameter of the bar. Consequently I need to define contact between this leg and the base it resides in. So I do the following:


I define boundary conditions that constrain all degrees of freedom of on end of the base.
I set up an Interaction with surface-to-surface contact between the leg and the base that it's inside.
I define an Interaction Property with only Friction, setting the coefficient of friction to 0.3.
All other details of the Interaction are at Abaqus default.



I run the model and the mode shapes of the leg are such that they go straight through the base. Clearly the contact is not even being recognized. It seems like setting up contacts should be easy but clearly I am doing something wrong. Also, there are no forces, I'm just trying to determine the natural properties of the structure (mode shapes, natural frequency, etc). I would greatly appreciate any help. Thanks! I'd be happy to provide any more details.



Thank you