Superposition Loadcase for Optimization

XxComposite69xX
XxComposite69xX New Altair Community Member
edited May 2023 in Community Q&A

Dear fellow FEM Engineers,

I am using Optistruct to perform topology optimization on a part with multiple loadcases. The loadcases are all linear static.

Is it possible to linearly superposition the loadcases/responses?

My part is symmetric and i can only effort to model one half. I have symmetric AND asymmetric loadcases which i wish to superposition.

thanks for your help!

Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited May 2023

    The Topology optimization can take into account all your loadcases in parallel. You don't need a superposition per say. Just add all of them into your model, and in your objective and constraints a reference to these loadcases.

     

  • XxComposite69xX
    XxComposite69xX New Altair Community Member
    edited May 2023

    The Topology optimization can take into account all your loadcases in parallel. You don't need a superposition per say. Just add all of them into your model, and in your objective and constraints a reference to these loadcases.

     

    But there could be multiple subcases acting at the same time. I am looking for a method to combine loadcases. For example: a wing which has aerodynamic and inertial loads acting upon it. This could be combined into one loadcase by using "LOADADD" and "SPCADD", In my case it is a bit more complicated.

    I have a symmetric part, which experiences unsymmetric loads. To save on computational complexity i only model half the part and devide the loadcase into a symmetric and an asymmetric loadcase with different boundary conditions (spcs at symmetry plane). Now i would need to superposition both results to obtain the results i am interested in. This is already possible in Hyperview by using "Derived Load Cases". However I need this for the optimization with Optistruct.

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited May 2023

    But there could be multiple subcases acting at the same time. I am looking for a method to combine loadcases. For example: a wing which has aerodynamic and inertial loads acting upon it. This could be combined into one loadcase by using "LOADADD" and "SPCADD", In my case it is a bit more complicated.

    I have a symmetric part, which experiences unsymmetric loads. To save on computational complexity i only model half the part and devide the loadcase into a symmetric and an asymmetric loadcase with different boundary conditions (spcs at symmetry plane). Now i would need to superposition both results to obtain the results i am interested in. This is already possible in Hyperview by using "Derived Load Cases". However I need this for the optimization with Optistruct.

    the simplest way is to use LOADADD and SPCADD as you've mentioned, as in a linear model they will act just like the derived results.

     

    Other than that, I don't know, honestly.