set responses in topology optimisation

Altair Forum User

Hello everyone,

 

I am trying to do mass optimisation for a part in Optistruct, but i was confused when i set a responses, there are so many responses, such as 'compliance, volume, static displacement, volume fraction“ and so on. I did read some tutorials and guide about the responses, and also the definition of the responses. But its for me is like a general information, i still have no idea which responses should I choose, when i set up my model.

It would be very nice if you can introduce me the principle of choosing the responses or share me more specifical examples or tutorials or whatever more to make me clear.

 

Thank you very much

Best regards,

Dong

tinh

Hi,

Select responses depending on model requirements.

If you just want to reduce mass, select 'compliance' as objective and 'volume fraction' as constraint

If your model has stiffness requirement => constraint 'static disp' also

If your model has eigen frequency requirement => constraint 'frequency' also

Altair Forum User

Altair Forum User said:

Hi,

Select responses depending on model requirements.

If you just want to reduce mass, select 'compliance' as objective and 'volume fraction' as constraint

If your model has stiffness requirement => constraint 'static disp' also

If your model has eigen frequency requirement => constraint 'frequency' also

 

Hey tinh,

 

Thank you so much for your replay. I have another question, hope you can help me

I know that 'Volume fraction = (total volume at current iteration – initial non-design volume)/initial design volume'

When I set the volume fraction as constraint, i guess it should be as upper bound, and then which value should I define for it? What is the principle to define the factor of the upper bound, when the constraint is volume fraction?

 

Thanks a lot

Best regards,

Dong

tinh

Hi,

I don't know recommended value for upper bound of volfrac

if you try several values, you may get several concept designs

then you can continue to optimize size/shape of concepts to satisfy disp/stress limit

Ravinder

Hello Tinh,

 

My  Model has stiffness requirement in topography optimization, which is sheet metal so, what will be best responses, constraint,and objective.  we can give  to get the accurate  beads.

 

Hope you can help me 

Adriano A. Koga

if i'm not wrong you could just use objective: minimize compliance (response: compliace == inverse of stiffness), with no constraints.

I believe topography accepts compliance (not quite sure right now...).

 

Or if it is not allowed, then try to create a displacement response, for the region of interest (a single node), and add this a objective: minimize Displacement.

 

 

For topography you might want to turn on some symmetry constraints (pattern grouping) to get more feasible designs.