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.

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  • Greetings, 

    It would be nice if you would share some of your test data and clearly indicated the location, amount of, and direction of movement for a few different size fittings. 

    Regardless, if you have physical test data that shows additional rotational movement, then suggest that you make changes to settings that directly affects a fitting's flexibility characteristics.

    Example, for a bend component, change Flexibility factor from Automatic to a user defined value base on your test data. 

    Regards,
    Mike Dattilio
    Design Analysis Engineering Group
    Senior Analyst Bentley Systems Inc
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  • We can do this for elbow (bend) fittings; however, there does not appear to be a flexibility factor input for 'T' fittings. Is there a way to put in a flexibility factor in 'T' fittings?

    Also, this tested flexibility factor will most likely vary on a case-by-case basis so I am unsure of how we could apply it across a whole pipe system at this time.

  • Hold on, I need to back up here and start over.

    You claim to have test data that shows fittings moving axially and rotationally due to applied loads. I cannot see how you are modeling your fittings in AutoPIPE. Are you modeling fittings using the adjacent piping Pipe Id, or other?

    Regardless, AutoPIPE will consider the geometry and material settings of the PIPE ID specified across 2 adjacent node points. Unless you modeled the fittings with rigid properties, the length of a tee’s legs and full arc of an elbows are considered when applying all loading conditions.

    You may consider inserting new PIPE ID as needed to correctly model fittings geometry and material properties. Be sure to apply the correct PIPE ID across the model. Recommend using AutoPIPE’s  Pipe Identifier (Show > Properties > Pipe Properties > Pipe Identifier) command to clearly see.

    As mentioned above, to help refine the model, you can manually change a bend's flexibility factor or newly suggest modifying the respective PIPE ID as needed. 

    If you have any further comments, please provide a simple detailed example of some piping geometry, PIPE ID data, and movement seen in AutoPIPE compared to your test data.

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