Simulate oscillations after displacement of a metal rod with a known weight on top

Hi there,

I am trying to simulate a metal rod that is fixed at one end and pointed upwards where it has added mass of 25 lb. The rod is then displaced by the known distance and let go. I am interested in how changing the diameter of the rod will alter the oscillation over a period of time and what the stress distribution will be at base of the rod. The part looks like this.

If anyone could point me in a direction of what type of study would be most suitable to use for this kind of a simulation I would be very grateful. The file is attached below.

Thank you in advance,

-Simon

SolidworksSimulation