Constraint optimization [CFD applications]

[abdussamad77]

I have one set data with 3 variables (v1,v2 and v3). I was trying to use surrogate (RSA,KRG,RBNN and PBA) approach for optimization.
[The surrogate are described here: pdf.aiaa.org/jaPreview/JTHT/2007/PVJA30211.pdf]

I can not accept optimum design which produces 2*v1>v2, because of geometric constraint.

I am using fmincon function (MATLAB), I tried to applied the constraint in fmincon:
fmincon(@fun, x0, [2 -1 0], [0], [], [], lb,ub)
but it did not produce desired result.

If I do not apply constraint criteria, all the surrogates are producing optimum design with v2 touching the lower boundary of design space and this is violating the 2v1<v2 criteria.

Any suggestion?

[Rafi Haftka]

As I noted in a previous post fmincon is not a good optimizer. If you have to use it, you may consider transforming the variables so that the constraint will be simplified to a bound constraint. So, for example, if your constraint is 2v1-v2>0, you can replace v2 by v2'=2v1-v2, so that the constraint is v2'>0.

Rafi

[abdussamad77]

Dear Prof Haftka,
Thanks for the suggestion.
I will try as per your instruction.

Abdus Samad
Inha University
Republic of Korea