comparison of compliance

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hello,

i would like to compare the Optistruct Topology optimization and the new Ansys Topology Optimization in relation to the optimization result.


At first I would like to compare the results of the two solver with the minimum compliance as objective.

 

I plan to run several optimizations with 90, 80, 70 … 10% as volume constraint.

The result should be a graph with the volume on the x-axis and the compliance on the y-axis. Each run is one point in the graph.

 

Now to my problem:

I thought the results are in a comparable range, but the values are very different.  For example, the result of the last iteration with 20% Volume constraint:

Optistruct Compliance: 858 Nmm

Ansys  Compliance: 4153Nmm

 

It is exactly the same part. The result is relative to the displacement is also comparable.

 

Now I doubt whether it is really useful to compare the results with the compliance.

Are deviations of this magnitude realistic? Makes it sense to use the compliance for comparison in your opinion, or do you know a better possibility?

 

Thank you very much

 

Andreas

 

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Answers

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited June 2016

    It is not recommended to compare two solver results. Are you comparing stresses?

    Refer Optistruct user guide for more info.

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  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016

    Rahul, thank you for your quick answer.

     

    so i think its bettet to reanalyse and compare the stresses and the displacement.

     

    For my argumentation. Can you tell me whats the reason that it is not recommended to compare the solver result directly?

     

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited June 2016

    Multiple reasons:

    Different method like for Optistruct modal analysis it uses Lanzos solver but Ansys uses other,

    While Post processing in Hyperview for stresses.Elemental or nodal (corner data) or Averaging method etc.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2016
    Altair Forum User said:

    so i think its bettet to reanalyse and compare the stresses and the displacement

     

    Better do a re-analysis with same mesh size and compare the displacement results and stress results. Different solvers use different algorithms.

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