Card that relates design variables
Altair Community Member
Updated by Joao_21860
Hello everyone,
I am running composite size optimizations and I came across a problem. I need to relate the thickness of different design variables (plies), however, there are no constraints available that address this issue.
Is there any CARD that allows me to create such a constraint?
*actually, the dependent design variables should be in a specific thickness range (e.g., 0.5t<t1<t), where t is the thickness of the 'main design variable' and t1 the other design variables.
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Altair Community Member
OPUpdated by Joao_21860
Thanks for your reply.
The second approach seems to be what I am looking for. I will try it and give a feed back later.
for size optimization problems you could create dervar links combining 2 or more design variables, by creating some relation using them.
with desvar link you could say for example: t1 = 2*t2
It can be created as DESVAR LINK1 or 2.
1 is linear relation, and 2 you can create an equation using DEQUATN. Try looking at them in the Help for OptiStruct.
The other way of performing this kind of relation is though a design constraint, just like any other optimization constraint.,
You can create a response of type 'function' (DRESP2) and assign it with an equation (DEQATN).
Then you assign the design variables? (t1, t2, t3...) and create an expression, such as 'F(t1,t2)=abs(t1-t2)'.
Having this relation you could specify a dconstraint and limit the difference to some value, using upper or lower bounds.