How to improve the modal participation factor

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

I am using the Flex Prep tool of Motionview to generate a flexible model in my multibody model (from a .fem of optistruct). At the end, I do not obtain high modal participation factors for selected modes. First 3 modes have a factor of 0.15, 0.05 and 0.03. After, it drops under 0.5%. I am looking to obtain a sum of participation factors close to 100%.

 

Where should I investigate to increase those modal participation factors ?

(Can you give me more details of how those participation factors are calculated ?)

Thank you,

 

Benjamin

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi,

     

    Use PFMODE to output Modal participation factor in H3D or Punch file formats. This option is available in Global_Control_Cards in OptiStruct. Insert the card before you prepare for flexbody.

     

    You can also try HGMODFAC Available in Global_Control_Cards>> OUTPUT this will output for HyperGraph.

    <?xml version="1.0" encoding="UTF-8"?>PFMODE.PNG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Coming to how to change modal participation factor, Modal participation for a mode somehow depends on Mass. So mass is the key variable. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Thank you for those informations !

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    When using the Flex Prep, the .prp file does not contain the PFMODE that I added in the .fem file of OptriStruct.

    How can I add it ?

    Thank you,

    Benjamin

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2016

    Hi Benjamin,

     

    Add, PFMODE in base .fem file and try again.

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