How to put constraint in unigraphix/solidworks/CATIA/Creo for this problem

For my problem I need to place the 200 particles randomly or patterned (balls of 2 mm diameter (100 are copper and 100 are lead)) in a shaft having a blind hole. These particles need to collide with each other and also with the walls of the shaft. How to provide this kind of constraint to the balls and with the wall of the shaft. ( It need to behave like the movement of the pebbles in the water bottle, when they get excitation force). How to do this model. Kindly help me. I created some model in unigraphix.

This model is to be imported to ANSYS workbench to perform the modal analysis in order to get the natural frequency.

I tried this in unigraphix and imported to ansys to do this, but it shows error

software is not a problem. I am ready to solve this in any software, my need is to identify the natural frequency.

Kindly help me to solve this case.