| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | ALL; |
| Area: | Calculations |
| Date Logged & Current Version |
July 2022 12.08.01.010 |
Problem:
Help understanding the changes to the sustained and occasional stresses from ASME B31.1 2018 to 2020?
Solution:
See help page “Bentley AutoPIPE > Command Reference > Result Commands > Result Options Group > Model > Apply B31J Gen. note (d)”). This option may be responsible for the difference in stresses for models
In order to match stresses between 2018 and 2020 models, user can uncheck this result model option to obtain similar in-plane and out-of-plane SIFs for sustained and occasional load combinations. It is recommended to go over the help page for this option for further detail.
Another reason for discrepancies may be related to incomplete information on selected components. Example, Contour Tees have a setting for Crotch Radius and Crotch Thickness. Note, B31J code requires the use of a different SIF calculations pending the value of these settings. Again, the code gives the user an option of which SIF calculation will be use based on component values entered.
Starting in ASME B31.1-2020 the code takes away the option and forces stress calculation for sustained, occasional, and thermal loads to use flexibility and stress intensification factors from the ASME B31J standard. Due to this requirement, the ‘UseB31J’ check-box in the general model options has been set to checked and disabled for this code year. More detail on the use of these factors can be found in the ASME B31J help section.