Imposed Loads (Forces & Moment) from One Autopipe Model to Another

Hi,

I have 2 Autopipe Models which are interconnecting to each other. One model is tie-in spool model and another is piping model.  I need to extract the forces & moments from tie-in spool model and imposed it in piping model. The tie-in spool has anchor support at the end of it. My question is what is the correct way to extract the load , is it under force & moment tab or under Anchor tab? The magnitude of forces & moment under these two tabs are the same but the in opposite direction (+ve/-ve sign). When i reverse the segment of tie-in spool, only then I will get same direction of forces & moment under forces & moment tab and Anchor type.

What would be the correct way to extract the loads if the direction is in opposite ? For information, the axis system  for tie-in spool and piping are the same.

Parents
  • Good day to you Fifah, 

    Suggest that you model both models to an anchor location, and provide both model results to the structural people to correctly design the anchor.

    Recommend to not use a typical piping point, flange junction, branch connection, etc.. as shared point between 2 models. One cannot just take the forces and moments results from one model, insert them into the next model, and assume that further analysis results with these values would be correct.

    The most important aspect engineers forget about is the stiffness of the adjoining piping systems. In some rare cases it maybe simple to consider adjoining model stiffness, but for most, correctly representing model stiffness in another model file is very complicated. Furthermore, dynamic analysis cannot be performed on models that do not share an rigid anchor node point. Remember from your AutoPIPE advance training, modal analysis results must exist before performing a dynamic analysis. A modal analysis calculates the natural frequencies and mode shapes. This calculation considers the total mass and Mass Degrees of Freedom for every node point in the model. As of March 2020, Modal analysis cannot be analyzed across multiple model files. 

    To answer your questions:

    Question: What would be the correct way to extract the loads if the direction is in opposite ?

    Answer: 

    The reason for the opposite directions, is the same as What does (node number) + / - mean in AutoPIPE's output reports.. After reading AutoPIPE help about how the Force and Moments are calculated you will understand that there is no need to reverse segments. Again, send the AutoPIPE Support report and Restraint report to your structural department. 

    Regards,

    Mike Dattilio
    Bentley Systems Design Analyst
    Design Engineering Analysis group
    ===================================================

     Also See:

    AutoPIPE WIKI here

Reply
  • Good day to you Fifah, 

    Suggest that you model both models to an anchor location, and provide both model results to the structural people to correctly design the anchor.

    Recommend to not use a typical piping point, flange junction, branch connection, etc.. as shared point between 2 models. One cannot just take the forces and moments results from one model, insert them into the next model, and assume that further analysis results with these values would be correct.

    The most important aspect engineers forget about is the stiffness of the adjoining piping systems. In some rare cases it maybe simple to consider adjoining model stiffness, but for most, correctly representing model stiffness in another model file is very complicated. Furthermore, dynamic analysis cannot be performed on models that do not share an rigid anchor node point. Remember from your AutoPIPE advance training, modal analysis results must exist before performing a dynamic analysis. A modal analysis calculates the natural frequencies and mode shapes. This calculation considers the total mass and Mass Degrees of Freedom for every node point in the model. As of March 2020, Modal analysis cannot be analyzed across multiple model files. 

    To answer your questions:

    Question: What would be the correct way to extract the loads if the direction is in opposite ?

    Answer: 

    The reason for the opposite directions, is the same as What does (node number) + / - mean in AutoPIPE's output reports.. After reading AutoPIPE help about how the Force and Moments are calculated you will understand that there is no need to reverse segments. Again, send the AutoPIPE Support report and Restraint report to your structural department. 

    Regards,

    Mike Dattilio
    Bentley Systems Design Analyst
    Design Engineering Analysis group
    ===================================================

     Also See:

    AutoPIPE WIKI here

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