Optistruct composite analysis (failed output results)

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

Hi,

 

I'm have to run a composite optimization with Optistruct and so I followed all the tutorials set-up steps, but at the point of running the static analysis the results that I obtain doesn't make any sense (displacement 411 cm...). I imagine it could be a problem of units but I've checked them and I cannot find out where the problem is. I've had defined the 'DTI_UNITS' card with the units Kg,N,mm,s and I've also set all the values introduce into these units. Even the value of the G force applied is -9810 (mm/s2). So I really don't know where the problem comes from.

 

I send attached the output file results. If you need any other information to help me solving this, tell me please. Thank you very much in advance.

 

Unable to find an attachment - read this blog

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hello,

     

    For a static analysis, i dont think dti unit card doesnt really has an effect.

     

    Maintain unit consistency in your model and try again

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hello,

     

    I've changed just the units of the G force from 9810 (mm/s2) to 9.81 (m/s2) and maintain in Kg,N,mm,s all the other values (material properties, etc). Now the results are good. Is it ok that the G force is in m/s2 while the other values are in mm?

     

    Thank you for your answer!

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Hello,

     

    You can calculate for your self :)/emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' /> using F= Ma.

     

    Newton=  Kg* m/s^2. So what you are using makes sense.

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