Stress Summary settings does not appear to be using the envelope WIND load case combination in Eq. 9 when using AutoPIPE, why?
Example, Given the following:
P1 = 300 psi, T1 = 105 deg f
P2 = 300 psi, T2 = 40 deg f
Equation 9
Hand calculations = 4537 psi
AutoPIPE results = 4224 psi
Why the difference?
Per this example, WIND 117 seems to be a legitimate combination and the program results are also correct based on the intent of the example. The only difference between program calculations and the hand calculations seems to be the use of Global wind moment values are used in the hand calculations, instead of using pipe local wind moments as done by the program.
For hand calculations, both Global and Local moment values for wind 1, wind 2, and wind 117 are given below:
The resultant are correctly calculated as 599 ft-lb for WIND 117 looking at the local forces and moments.
Again, written example above uses Global loads and their calculation is also correct using these figures. However, it is the Local resultant that is used in AutoPIPE's stress calculation and not the Global values. and may lead a user to question the results. However, they are correct.
"Stress Summary" sub-report using Results> Output Report
Bentley AutoPIPE