Optistruct composite analysis (failed output results)

User: "Altair Forum User"
Altair Forum User
Altair Employee
Updated by Altair Forum User

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.

 

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    User: "Altair Forum User"
    Altair Forum User
    Altair Employee
    OP
    Updated by Altair Forum User

    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

    User: "Altair Forum User"
    Altair Forum User
    Altair Employee
    OP
    Updated by Altair Forum User

    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!

    User: "Altair Forum User"
    Altair Forum User
    Altair Employee
    OP
    Updated by Altair Forum User

    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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