How to Account for Rotational Moment in Pipe Threading

How can you account for movements within pipe-to-fitting thread engagement? Movements in the threading can occur axially and rotationally  at varying load applications.

Autopipe does not seem to have an input for fittings or connections that accounts for thread engagement behavior.

  • The ‘T’ fittings do not have a flexibility factor option unless there is a way to input it outside of the modify tab in autopipe.
     
    In regards to using different pipe ID’s, we are modeling the pipe with different pipe ID’s (see model attached) since the materials are different between the cast iron fittings and the piping. However, this still does not model the behavior of the movement that occurs in the threaded connections specifically.
     
    Nick Baker
     
     
  • Greetings, 

    When sharing an AutoPIPE model with a user that does not have access to the same folder location where the model is stored, one should always send an AutoPIPE APC file. Highly suggest to not send an DAT file. 

    You are correct that there is no Flexibility factor for a Tee fitting. I had a look at the dat file provided, however you failed to provide detailed information on exactly what is the observed concern. You claim to have test data that shows fittings moving axially and rotationally due to applied loads. Where is the test data for this size pipe, with this piping arrangement, and this GR loading? What are the expectations?

    I can see that the applied load at the end of the pipe is causing the Tee node point (A03) to displace vertically down -0.00015726518 inches.

    Are you expecting to see more or less move movement at this location ?

    There is nothing in this model to indicate that A03 would experience a torque about the axis direction of the pipe (along the header direction of the tee). If your test data indicates this phenomenon then you can manually apply a concentrated force at the fitting node point(s) with the direction and magnitude as needed. Suggest that the concentrated force(s) be applied to the GR load case.

    If the issue is related to the pipe twisting because of this arrangement and loading configuration, please share some insight as to what is causing this twisting, share your test set up, and the observed results. 

    Regards,
    Mike Dattilio
    Design Analysis Engineering Group
    Senior Analyst Bentley Systems Inc
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  • Greetings, 

    Please discuss with Eric MacFarlane. 

    Regards,
    Mike Dattilio
    Design Analysis Engineering Group
    Senior Analyst Bentley Systems Inc
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