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Message ID: 19     Entry time: Fri May 27 02:09:37 2016
Author: Gabriele 
Type: Mechanics 
Category: Characterization 
Subject: Lowest usable mode of fused silica disks 

I did some FEA simulation of fused silica disks, to identify the lowest usable eigenmode. By usable I mean a mode that has zero elastic energy stored in the center. 

Diameter Thickness Frequency
75 mm 1 mm 2500 Hz
100 mm 0.4 mm 564 Hz
200 mm 0.4 mm 141 Hz
75 mm 0.12 mm 293 Hz

In the attached figures, the dfisk deformation is shown exaggerated, and the color map shows the elastic energy density. All results are obtained with COMSOL/MATLAB, the disk are constrained at a point corresponding to the center of the lower surface. No gravity.

Attachment 1: disk_75mm_0.12mm.png  78 kB  | Hide | Hide all
disk_75mm_0.12mm.png
Attachment 2: disk_75mm_1mm.png  85 kB  | Hide | Hide all
disk_75mm_1mm.png
Attachment 3: disk_100mm_0.4mm.png  81 kB  | Hide | Hide all
disk_100mm_0.4mm.png
Attachment 4: disk_200mm_0.4mm.png  82 kB  | Hide | Hide all
disk_200mm_0.4mm.png
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