How to determine volume fraction value

Altair Forum User

Hi all,

 

I'm new at optimization. I have been trying to optimize a 3d design space part ( in red.Pic1 ) between 2 Frames in 3d ( in blue.Pic1 ) with aid of tutorials.

I set up the model. I specified objective as minimization of weighted compliance and constraint as volume fraction.

But i couldn't decide value of volume fraction, and i see that the value is most time =30% but i dont knwo why you choose this value and how can we justify this choice ?

Can anyone help me about this issue?

 

Best Regards

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Altair Forum User

HI,

 

It will be easy if you understand how Volume fraction works,

 

Lower bound set to 0,4: the solver takes minimum 40% of the original volume to optimize. If you do not constraint an upper bound as well it might go to 100% if it is structurally necessary

 

Upper Bound set to 0,4: The solver is allowed to take maximum 40% or less material for the optimized design.

Altair Forum User

Altair Forum User said:

HI,

 

It will be easy if you understand how Volume fraction works,

 

Lower bound set to 0,4: the solver takes minimum 40% of the original volume to optimize. If you do not constraint an upper bound as well it might go to 100% if it is structurally necessary

 

Upper Bound set to 0,4: The solver is allowed to take maximum 40% or less material for the optimized design.

 

 

Thank you very much,

 

Please what is the principle to define the factor of the upper bound, when the constraint is volume fraction?

 

Regard.

Altair Forum User

Altair Forum User said:

Please what is the principle to define the factor of the upper bound, when the constraint is volume fraction?

 

To start with use a lower bound of 0.3 and upper bound can be free where solver can take up to 100% material