I'm trying to use a design study to optimize geometry so a cross section has a moment of area that's equal to a certain value. For simplicity, let's say I'm changing wall thickness in hollow structural steel with a rectangular cross section (height and width will remain constant again for simplicity). I believe I need to insert a global variable which equates the second moment of area based on the extrusion sketch dimensions. Is there a better way to do this?
I reference the I_x variable above in my design study.
When I run the optimization, the global variable I_x doesn't update so there's no convergence to the solution.
You can see I_x remains constant even though the wall thickness is changing. This is obviously an error. Can anyone think of a better way to approach this? Solving for the wall thickness directly would be an option but I would like to work with various other types of cross sections that would all need unique equations.