maximize the frequency gap

Rahul_P1

i am doing a shape optimization of a 2D circular plate with some holes on it. it has 10 eigen frequencies like w1,w2,w3,w4....w10 in the prescribed range. i have to optimize the position of the holes as well as the radius of each hole so as to maximize the gap between any two frequencies. .

so my design variable is
1. Position of the hole from center of circular plate
2. radius of the hole.

Objective
maximize all the frequencies gaps , w2-w1, w4-w3, w5-w4 ....w10-w9

Could anyone please give me some hints how to do it.
Regards.

Rahul_P1

Hi,

please look at the Optistruct Tutorial (Help -> other applications -> tutorials) OS-5040: Shape Optimization of a Rail Joint for the general approach on a shape optimizations. The general steps are:
1) Use HyperMorph to define all possible shapes. Save each independent shape variable.
2) Create on design variable for each shape (optimization -> create -> Shape desvars)
3) Create responses for each frequency (optimization -> create -> response -> response type frequency)
4) Create a dequation describing the gap (e.g. f(w1,w2,w3,w4,...)=abs(w2-w1+w4-w3+...) through optimization -> create -> design equation. The equation might look different, if your task is somewhat other than I understood.
5) Create a response of type 'function' for the gap between the frequencies. Edit this response once and the hit the create button
6) Maximize the funtion response (optimization -> create -> objective)

Regards
Jan