Convert a part in a datum

[Yuopaznn]

Hi,
I did a product on catia with 2 solids elements and an axis (I want to join 2 solids plates with a bushing constrain in the direction of the axis). I convert this product in .stp and I import it on Abaqus. Abaqus consider the axis as a part and I just want that it consider it as a datum. So how can I convert a part in a datum?
Thank s for answer.

 

[Yuopaznn]

I finally find a solution: In the tree, assembly, Instances, right click on the axis, Exclude of the simulation