Dear Sirs,

Ceasar II's report as below:

"NODE 20; Axial Stress: 12925.9(KPa); Bending Stress: 5482.8 (KPa); Torsion Stress: -2777.6 (KPa); Hoop Stress: 32583.3 (KPa); Max Stress Intensity: 71709.7 (KPa); SIF In Plane: 1.0; SIF Out Plane: 1.0; Code Stress: 20726.2 (KPa); Allowable Stress: 117900.3 (KPa); Ratio: 17.6 %; Piping code: B31.1"

As per B31.1, we have: Code stress = (Bending stress) + (Hoop stress/2)=5482.8+32583.3/2=21774.45 > 20726.2 (Ceasar II's report).
Please help to advise for this result.

Thanks very much.

"Axial+Bending" will be the code stress when "pressure" term included such as Sus,Occ and Hyd. This will be checked to the Allowable (117900 Kpa).

"Bending" only will be your code stress when there is no "pressure" included such as Expansion case.

Yes, this case is sustained loadcase, as per B31.1: Code stress = Bending stress + Longitudinal stress(Hoop stress/2) = A

Because code stress is calculated the same way with A, so why it is difference from A???It's my concern.
Please advise more.
Thanks.

Don't use the stress components in the stress report to re-compute the Code Stress. You must start with the forces and moments and perform the actual stress calculation required by the Code for the load case in question.

(The bending stress reported is just that "bending". Bending stress = SQRT( my^2 + mz^2 ) / Z. However, B31.1 includes torsion in its bending stress, so that Code equation term is: bending stress = SQRT( mx^2 + my^2 + mz^2 ) / Z.)

The longitudinal pressure term is not "hoop/2", unless you've activated PD/4t. By default the longitudinal pressure term (as defined in the Quick Reference Guide) is: P * di^2 / (do^2 - di^2)

Thanks Mr. Richard.

What is the stress type (sustained, expansion, occasional, "operating")?
There are different stress formulae.

Dear Dave Diehl,

I find the explanation for my problem from Mr. Richard's response.
Anyway, thank you for your help.