Square Flange Problem - VIII, App. 2, 2-10

[reesh]

I have a square flange that has to be analysed to B31.1. I'm trying to use Sect. VIII, App. 2, 2-10 for noncircular flanges. The problem I get is that when I apply that method to the flange, the outer diameter A is smaller than the bolt circle diameter C.

Is there another method to analyse this flange or does it simply not meet Code?

 

[prex]

If I recall correctly, you can analyse a flange per App.2 even if A<C.
However 2-10 may be really too conservative, depending on the proportions of the flange.
This doesn't mean the flange is not complying with code, but if you can't satisfy 2-10 then you could be facing a difficult problem: of course you could make an analysis by FEM or by formula, but after that demonstrating the compliance of calculated stresses to App.2 is not an easy task.

prex

http://www.xcalcs.com

Online tools for structural design

 

[reesh]

Thanks! I've been spoiled in the past in only having to deal with "typical" flanges.

 

[arto]

Also, check out: "Bolted Flanged Connections for Non-Circular Pressure Vessels" by A.E. Blach of Concordia University in Montreal. 1989 PVP 158