I'm having issues in understand how to properly set a topology design with frequency constraint.
The aim is to minimize the mass achieving a 1st natural frequency higher than 510 Hz.
The item of the optimization is an aluminum rectangular box, from which I'd like to remove material leaving a "skin" of 0.3 mm at the bottom, with a ribbed structure to obtain the proper stiffness for the > 510 Hz first eigenfrequency. I did different attempts, but what I always achieve is a "messy" structure (unless I set "uniform in ## plane", but I prefer leaving Creo free to put material where necessary, and then adapt the material manually extruding various geometry ribs following the suggested material distribution) but most of all, when I proceed with the geometry reconstruction, I obtain a component that won't satisfy the frequency constraint. After a modal simulation, the 1st eigenfrequency is in every case way lower than the 510 Hz I've set.
I premise that I'm a beginner with Topology Optimization on Creo, but I really cannot understand where I am failing in setting the problem, having understood the principle and the different parameters I can "play" with. Eventually, if someone could help me, I can provide more information about both the component and the parameters I've set during the optimization attempts.