Hey guys,

This may be a seemingly uneduated question, but I am having trouble wrapping my head around it so please bear with me on this one.

I am wanting to simulate a highly pressurized tank, an accumulator to be exact, that will be at 30k psi. I do not have the pressure vessel simulator on the system I am currently using so I am simply using SimulationXpress (SW 2012) to simulate the pressure of the tank. I am getting results, but they are very hard for me to believe. I have made a custom material to simulate 410 SS and am ultimately trying to come to a safe OD and ID of the vessel that we will potentially manufactur. I am not seasonsed in the design of pressure vessels so I have been somewhat shooting in the dark on this one.

When I run my simulation, I get super low FOS but it appears that SW is showing maximum localized stresses along the ID of the tank. I realize that this will be the case but even creating a tank that has a VERY small ID compared to the OD (we're talking something around a 2" ID, 12" OD just to test) I still get a FOS less than 1.0. Is the method I am using not appropriate for what I am wanting? I've attached a picture of what I am seeing. Any help or general guidance on this is greatly appreciated.

ADDITIONAL INFO:

Modeling after a 12" OD and a 36" length just to get a baseline of what will be safe wall thickness using the 410SS.