Buckling constraints in the wing box optimization problem

[Gittwell]

Dears colleagues!

Please tell me, how I can set up optimization with a buckling constraints. I use tacs 3.3.1 and mphys 1.1.0.
I can add KSFailure constraint,but I can't find any information on how to add buckling constraints.

model.add_constraint("tip_shear.ks_vmfailure", lower=0.0, upper=1.0, scaler=1.0

[timryanb]

Constitutive classes like BladeStiffenedShellConstitutive will include buckling in their KSFailure calculation (in addition to the normal stress-based failure check). Though we could do a better job of documenting this information.

[Gittwell]

Thanks for the reply, this will help me a lot. Can I ask a few more clarifying questions?

1. I saw a failure setting in the new version of tags (but i can't use tacs 3.8.0 in aerostract problems. Adflow cannot work with mphys 2.0.0):

con.setFailureModes(
includePanelMaterialFailure=True,
includeStiffenerMaterialFailure=True,
includeLocalBuckling=True,
includeGlobalBuckling=True,
includeStiffenerColumnBuckling=args.includeStiffenerBuckling,
includeStiffenerCrippling=args.includeStiffenerBuckling,
)

Is this setting not supported in older versions yet?

2. BladeStiffenedShellConstitutive includes in KSFailure Local, Global and Stiffener Buckling?
3. IsoShellConstitutive include buckling in KSFailure?

[timryanb]

1. No, you'll have to update to a newer version to use these features.
2. Yes, I believe this is the case. @A-CGray can correct me if I'm wrong.
3. No, IsoShellConstitutive doesn't have any buckling calculations

[A-CGray]

Hi @Gittwell, you can either checkout TACS 3.7.2 which is the last release before the mphys wrapper update, but doesn't contain the improvements I added in #319, including the 2 stiffener buckling modes. Or you could checkout the last commit before we updated the mphys wrapper (f3c69ea) which will include the most recent improvements to BladeStiffenedShellConstitutive.

[Gittwell]

Thanks, I'll try to use version 2.8.0 before mphys update. I think new features are very useful.

[Gittwell]

Hello, thanks for your answers, they were really helpful. Could you also clarify for me? Can I use BladeStiffenedShellConstitutive for an isotropic material? I found an example in the tests (https://github.com/smdogroup/tacs/blob/master/tests/constitutive_tests/test_blade_stiffened_shell_constitutive.py), but I want to make sure.

[timryanb]

Yes, isotropic properties should work fine with BladeStiffenedShellConstitutive