RSS summation
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.
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Altair EmployeeJust 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.
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.