Posted by: badre
Longitudinal Stress - 06/20/14 04:17 AM
Hi all,
I have a question about B31.1 para 102.3.2 : there are 2 equations to calculate Slp, which one do i have to use ?
Regards,
Posted by: Dave Diehl
Re: Longitudinal Stress - 06/20/14 07:16 AM
The word "or" appears between them.
Use whatever equation you want.
CAESAR II defaults to the more exact "P*Inside Area/Metal Area" (your equation 2) but you can throw a config switch to use PD/4t (Barlow; your equation 1).
Posted by: badre
Re: Longitudinal Stress - 06/20/14 07:43 AM
Thinks Dave for your reply,
In fact, i used the first one but my colleague told me that i have to use the second because the thickness of pipe (42.4 mm x 7.11 mm) is greater than 1/10 the diameter !
I couldn't find this information.
Posted by: Richard Ay
Re: Longitudinal Stress - 06/20/14 12:39 PM
In my opinion you should always use the 2nd equation. The PD/4t equation is a "thin wall approximation" - the key word here being "approximation".