How to optimize problems with variable forces?

Altair Forum User

Dear user and support,

 

as you can see in the picture, I want to optimise a bending beam loaded with 2 forces, one of them variable and one of them static, using optistruct.

Force F1 is a constant load and Force F2 is a pulsation load.

What I did until yet is to create 2 loadcases, one loadcase including only F1 and one loadcase including F1 and F2 at its peak value.

But this is not exactly representing the true loading conditions.

However in this special case my result may be similar to the true result but using complex force paths it is not possible to represent these dynamic forces with static loadcases.

 

Summarized, I want to optimize problems with time-dependent loadings, using optistruct.

How can I optimize such special problems?

 

Thank you in advance!

Daniel

 

 

Altair Forum User

Hello Daniel,

 

One way to model this would be to use the equivalent static load method, in which you try to capture the dynamic behaviour using MotionSolve MBD analysis and then transfer the loads to OptiStruct optimization. See here in the help for details:

OptiStruct > User's Guide > Design Optimization > Equivalent Static Load Method (ESLM)

 

and

 

OptiStruct > OptiStruct Tutorials and Examples > Examples > Example Problems for Optimization with ESLM

 

Hope this helps you in solving your task

 Jan

Altair Forum User

Hello,

 

thank you for your advice!

I looked up the ESLM in literature and I think it is the function I need.

The problem is: I want to put in the force path depending on the time to set up my topology optimization (see picture). So I don't want to use the Multy Body Analysis (MBA) in prior to the optimization.

 

So how can I realize that?

 

 

Thank you in advance!

 

Daniel