Ok, here's the deal. I need to make calculation for very simple part.

I need to make calculations for that lower beam part (circled in red). It is fixed to floor and to that stretcher platform with 8M countersunk screws.

I have made the floor holes fixed and try to apply a force to upper holes. So that G forces goes lenghtwise and the faces that take the force are those screw holes. I have applied material as cast alloy steel, but for some reason even with smallest force applied the results appear very bad. Like this:

Im trying to this just for the part, not assembly. Any ideas what I'am doing wrong? The main goal here is to simulate 20G crash on this part, so I need to see where I put reinfocements etc... I tried to check the tutorials came with Solidworks, but looks like im going to need more help than those.