Optimization Tosca Eigenmodes Maximization 1

[dkakth]

Dear colleagues, can someone give me example of how to properlly setup an optimization with objective function = max first 5 EMs and volume constraint

Im using ABQ optimization module (buildin Tosca) and after the 5th iteration it crashes. My guess is it does not like how the dresp is formulated (eigenfrequency with Kreisselmaier - Steinhauser formula)...

 

[FEA way]

It is highly advised to use Kreisselmaier-Steinhauser formulation whenever possible. Especially if you want to maximize several lowest eigenfrequencies.

Which type of optimization do you use - topology, shape or sizing ?

Do you have mode tracking enabled ? If not, turn it on.

 

[dkakth]

Hello FEA way and thanx for your input !!!

Yes i forgot to mention - its about topology optimization

Indeed, i forgot "mode tracking" ;( 10x for remiding me

I use Kreisselmaier-Steinhauser formulation, but maybe the setup there (step, range etc) i make some mistake...

 

[FEA way]

Did you get any errors in the Optimization Process Monitor ?

What are your settings in Steps tab of Edit Design Response window for eigenfrequency design response ?

 

[dkakth]

This is the problem - i cannot locate the error into the messages: from the terminal i get "ERROR in Tosca for Abaqus - module FE Solver : abaqus. The optimization system is searching for check string "THE ANALYSIS HAS BEEN COMPLETED". The checkfile "Opt-Process-1-Job.msg could not be found. and this happens on the 7th iteration (design cycle)

In the \Opt-Process-1\SAVE.msg folder there are only 3 files - Opt-Process-1-Job_000, 001 and 005, so it seems it does not create such files idk why.

for settings - i am upploading the inp and par file, so you can see all settings on everything easily

 

[FEA way]

If you expand the Jobs container for this optimization process and open Job Monitor for the last job (the one that failed to complete) you will see more specific errors:

- Specified surface _pickedset13_cns_ does not exist. This surface must be defined.

- An error has occured while processing the coupling option. Please check the data file for appropriate messages.

For the coupling error, it seems that you have unnecessary coupling constraint in your model (there are no boundary conditions applied to it). Remove this constraint if you don’t need it.

Address these issues and the analysis should work fine. But check the warning messages too.