"force controlled" and "displacement controlled" loadcases

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

Hello all,

I have a question about the equations behind the difference between loadcases that use forces vs loadcases that use enforced displacements.
I am aware that these two loadcases lead to different results on Optistruct, but have found very few info in the help about it.

I did a simple test watching the behaviour of a part under torsion and bending when I try to optimize it on Optistruct (minimize mass, Von Mises static constraints, gauge optimization).
-When 'enforced displacements' are used, we obtain a lighter part ( decrease of the thickness ) but the stresses decrease as well ! This is totally illogical since a decrease of the thickness should necessarily lead to an 
 

Answers

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

    Hi @rimeca

     

    Is the thickness distribution is even through out the model after optimization?

     

    or is it like random?

     

    Maybe the thickness is less where there should be less stress and more where there is more stress.

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

    Hello Prakash, 

    Could you please read the other question I posted (with the same title) because it is the complete one. I was not able to delete the other one yesterday.


    To answer your question, I used a gauge optimization option where the thickness distribution is even.
    Thank you

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2016