I cannot seem to find out how CAESAR calculate allowable stress in bend nodes (according to B31.3) in an EXP load case. That is; the allowable stress in the nodes created by CAESAR when establishing a 90deg bend for instance. From what I have read, the allowable stress should be calculated according to

S = f(1.25Sc + 1.25Sh - Sl)

where Sl is longitudinal stress.
But whatever results I use to calculate the longitudinal stress, and further the allowable stress, I do not arrive with the same stress as the one calculated by CAESAR. Can anybody give me a hint?


Thanks!

That is the equation used, so you should be able to manually compute the same allowable that CAESAR II uses. If you can't, send the job file to "techsupport@coade.com" along with the details of the version of CAESAR II you're using (what version, what build).

Thanks for a (very!) quick reply.

Giving it a last shot before weekend, i think a got it right now.

When calculating the longitudinal strain I focused on the stresses in the EXP case, and tried to combine these in several ways without any luck.

Turning to the values from the same node in the SUS case, the numbers added up. Adding axial stress, and bending stress (without combining it with the torsional stress through sqrt(Sb +4St) made up the longitudinal stress necessary to arive at the same allowable stress as CAESAR through the formula

S = f(1.25Sc + 1.25Sh - Sl)

In my case, I had two SUS cases and CEASAR seem to use the strains from the most severe case. Have a vague recollection of reading this somewhere (maybe in B31.3?).

Think I have got this right no; the longitudinal stress in the equation above is the stress caused by weight and pressure and is found by adding axial and bending stress from the most severe SUS case (?)

Yes, you use the "SL" from the most severe Sustained case.