NOTE # 6544 Zero force will be applied on pretension

Casper Kruger
Casper Kruger Altair Community Member
edited December 2021 in Community Q&A

Hi,

 

I am running a bolted connection FE model in Hyperworks with preload. The results shows the preload being applied correctly and the 1D beam stresses corresponds to my hand calculation, but I get the below message:

 

NOTE # 6544
Zero force will be applied on pretension sections which are defined but
not explicitly loaded via PRETENSION command. Zero relative deformation
can be enforced there by PRETPRM,INILOAD,ZEROA instead.

 

Can someone please explain what this means? and if it is correct to get this? 

 

Thank you. 

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Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited December 2021

    are you sure the pretension force, section and PRETENS SET are correctly created and related to each other?

  • Casper Kruger
    Casper Kruger Altair Community Member
    edited December 2021
    Adriano A. Koga_21884 said:

    are you sure the pretension force, section and PRETENS SET are correctly created and related to each other?

    Hi Adriano,

     

    I created the preload using the preload manager, selected the beam elements, selected the load collector and set the force. 

     

    I run the preload as its own case and then run the preload as a CNTNLSUB with the desired load case. See attached the .HM file for reference. 

     

    The force, section set are created with the preload manager and linked in the load step by referencing it under preload. Or am I missing something?

     

    image

    image

     

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited December 2021
    Casper Kruger said:

    Hi Adriano,

     

    I created the preload using the preload manager, selected the beam elements, selected the load collector and set the force. 

     

    I run the preload as its own case and then run the preload as a CNTNLSUB with the desired load case. See attached the .HM file for reference. 

     

    The force, section set are created with the preload manager and linked in the load step by referencing it under preload. Or am I missing something?

     

    image

    image

     

    I don't remember exactly, but there is an output for pretension forces.

    You can request to make sure that your bolts are pretensioned or not.

    But the message looks strange.

     

    For pretension your setup looks right. Aren't you working with 'displayed' export for any reason, that might avoid something from your model of being exported? Or maybe you have a previous pretension section which is not being used anymore?

     

    For pretension, SET Pretens, points to the bolt element, and the pretension force is appplied to the bolt element too, as a 'flux' of type PTFORCE. The load collector for the pretension load is used by the pretension loadcase.

    Later on the pretension loadcase is carried by the next loadcase with STATSUB(PRETENS) + CNTNLSUB.

     

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