What was changed in how Restrained-Expansion is calculated using ASME B31.4 code for the bend arc between version 11.04.00.01 and version 12.01.00.09?

I was investigating discrepancies between a model run in version 11.04.00.10 and in version 12.01.00.09 using ASME B31.4 code. When a model created in v11 was opened in v12, total stress levels were observed to be 1-2% higher than in v11, with no changes made to the model. The incorrect expansion coefficients in v11 have been matched to v12.

At any given node, comparing between the two AutoPIPE versions of the same model, the stress level is 1-3% higher for the bend arc in version 12. The table below shows the data for a typical bend node, with the comparison between versions highlighted in yellow:

Except for the hoop and sustained categories, all other code combinations also had discrepancies in stress levels, although without the consistency of the Rest-Exp category. I can’t find any documentation as to what has changed.

  • Hello Lisa, 

    There can be any number of reasons why results between versions do not match. The most important being are they actually the same model. Just because a model is opened in 2 different versions does not make the models identical. Any data recalled from a library can be different or default settings may have changed. That is why it is always imperative to compare a complete output report from each versions in a program that can quickly indicate any differences (ex. Beyond compare, Ultra Compare, etc..). See WIKI page here for instructions to perform this comparison. 

    One may see a number of small differences, but one particularly may answer your question, material data from B31.4 and B31,8 libraries are different between 11.x and 12.x. This was documented in WIKI here of Known issues. AutoPIPE only publishes Critical and High severity issues to the general public. If you are apart of the QA program you get monthly updates on all public released severity issues Low, Medium, High, and Critical, among other perks.

    Regards,

    Mike Dattilio
    Bentley Systems Design Analyst
    Design Engineering Analysis group
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