How to determine volume fraction value

e_taralom

Hi all,

I'm new at optimization. I have been trying to optimize an automobile part 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. Honestyl i didn't even understand what volume fraction is. Can anyone help me about this issue?

Best Regards

Altair Forum User

Hello,

 

Volume fraction is the ratio between volume of design space at iteration i on initial volume of design space.

 

Benoit

Rahul_P1

Formulation for volume fraction:
Volume fraction = (total volume at current iteration – initial non-design volume)/initial design volume

 

we many times use 0.3 to start with , which means 30% of the 'design space' volume will be retained. 

 

In OS help , see - 

Altair OptiStruct > User's Guide > Design Optimization > Responses:

Internal Responses

e_taralom

thank you for your help.

Merula_20758

Finding the optimal value for your volumefrac is somewhat of a iterative procedude. So use 0.3 as a starting point and go from there....

 

maybe do a vf dconstraint of 0.4 and 0.2 and see, what changes.

 

Best Regards,

 

Merula