RSS summation

Mirhan Ozdemir_21843

Hi to all,

I am doing a optimization. In my optimization I meause frequency response displacement (real,rss of them) of 9 points as responses. After that, I sum them. My objective is minimizing summation of the displacements. I also have a constraint such that I dont want any resonance frequency between 2200Hz<>3200Hz. My optimization model frequency runs btwn 1500Hz and 5000Hz. once optimization is done I manually sum the 9 points displacements to compare it with optimization results. However, I see that results are different. When I sum displacement between 2200-3200 Hz the difference is 5% whereas when I sum them for a range of 1500-5000Hz the difference is 25%. My question is where does this difference come from? What is the optimization logic of optistucurt which range of frequency is summed by it for minimizing the sum displacements 2200-3200 Hz or 1500-5000Hz?

Thanks for your time.

Adriano Koga_20259

What type of optimization are you running? Size?

Can you share the .out file for more details?

 

Are you summing frf displacements in 9 different frequencies? I imagine the frf displacement is changing because your model are actually moving along the optimization. You are probably moitoring a few points and manually comparing other points, maybe.

Viraj Kulkarni_21218

Just a comment Mirhan. I understand you are trying to study effect on displacements. I wanted to add that if your aim is to avoid resonance between 2200Hz<>3200Hz, when you do optimization you can try to address this first. You can do that by increasing/decreasing specific frequencies which are near the specific range. You can also have lower/upper bound constraints. Once you have all the resonance condition satisfied, you can concentrate more to improve other parameters if you need.