How to find collapse pressure of a pressure vessel

[Chrissy123]

Hi - I am modelling a flat head pressure vessel and I am writing a script to vary the thickness of the head of the pressure vessel.
I have managed to do this but I now need to determine what is the pressure that causes the pressure vessel to collapse. How do I determine this please
from the results of the model ?

thanks,

 

[FEA way]

First you should perform linear (eigenvalue) buckling analysis to find the approximate value of critical load. Then you can either trace the postbuckling behavior up to collapse using Riks (arc length) method or analyze your structure with explicit dynamics solver which is perfect for such situations. It can show you the whole proces until there's pretty much nothing left from the vessel. However you should remember that it may take a lot of time to complete the simulation. You could also use static general or implicit dynamic analysis but convergence issues are more than likely.

 

[TGS4]

If this is a pressure vessel, then you ought to be following the rules in ASME Section VIII, Division 2, Part 5. There's more to it than plastic collapse, there are additional failure modes. Also it makes a difference of the flat head is welded or bolted.