I’m working in AutoPIPE Version 09.06.00.15, and I have a question regarding the calculation of hoop stress allowables for single cut, widely spaced miter bends using ASME B31.3 2012. AutoPIPE has two separate equations for single cut widely space miter bends depending on the angle of the miter cut, as follows:
When using a miter cut of exactly 22.5 degrees (i.e. a 45 degree miter bend), the bottom equation is used to calculate the hoop allowable instead of the first equation. I created the miter bends using cylindrical coordinates and 45 degree bends.
I have verified that the language in the code is consistent with the above snippet from the AutoPIPE Content Menu, and therefore I believe this may be an error in the software. Is there something I am missing regarding the equations used? Is there a reason the less than or equal to sign does not apply to a miter angle that equals 22.5 degrees.
Greetings Ashley,
I would suggest that you open the bend dialog and check that the bend type = Wide. Next, create a model input listing that includes Bend data listing sub-report and confirm the reported angle for the node point in question is indeed exactly 45 deg.
If you would show your values used for all of the variables used in the 2 calculations above. Also a snapshot of the output report showing what the program calculated.
Regards, Mike Dattilio Design Analysis Engineering Group Senior AnalystBentley Systems Inc=============================================================================
Mike,
Thank you for your response and pointing out the sub-report that lists the bend angles. This was helpful, and I have verified that all bends are exactly 45 degrees and bends are all wide. I'm still seeing the same discrepancy, so I've included the numbers you requested below.
Here are my calculations for each of the above equations:
Here is a snippet of the AutoPIPE BEND Data Listing and Code Compliance Listing (note I am using nominal pipe thickness and a simple model to simplify this discussion):