Section VIII, Div 2, component vs assembly level FEA

[hhamza]

When doing an analysis per Div 2, part 5, is it acceptable to do the FEA on each component separately or does it need to be done on the entire assembly at once?

For instance, say I have a pipe with two bolted on blind flanges on either end. Can I perform FEA on the pipe, flanges, and bolts (fatigue) separately or does it need to be done on the entire assembly at once? Does the code deal with this at all? Or are there any acceptable practices that I don't know of?

The reason I ask is that my system is having trouble handling the assembly. Doing component level FEA though runs pretty smoothly.

thanks,

 

[TGS4]

You component-level analysis - does it consider the interaction between the components?

 

[hhamza]

To some extent.
I can estimate an axial load due to the pressure on the flange and apply that to the pipe.
However, there are other interactions that would be missed. e.g. Flange could provide some stiffness that my component level FEA wouldn't take into account

 

[TGS4]

Interaction between components must be considered. If you can do that adequately in a component-by-component analysis, then that should suffice. If you can't, then an assembly-level assessment must be performed.