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Entry  Mon May 9 22:19:06 2022, Koji, Update, BHD, BHD Platform Progress status Screenshot_2022-05-09_220220.pngScreenshot_2022-05-09_222405.png
    Reply  Mon May 9 23:18:44 2022, Koji, Update, BHD, BHD Platform Progress status 6x
Message ID: 16840     Entry time: Mon May 9 23:18:44 2022     In reply to: 16839
Author: Koji 
Type: Update 
Category: BHD 
Subject: BHD Platform Progress status 

I quickly ran the FEA model to check the resonant freqs of the BHD platform.
The boundary conditions were:

  • The platform was not loaded
  • FIxed constraints were given to the five legs

Don has optimized the cut-out size for the OMCs to increase the rigidity of the plate. Also, the ribbed grid is made at the bottom side.

The lowest mode is at 168Hz. Because there is no leg around, it seems reasonable to have this kind of mode as the fundamental mode.
The other mode lined up at 291Hz, 394Hz, 402Hz, ...
The mode freqs will be lower once the platform is loaded. But as the unloaded platform mode, these mode freqs sound pretty good numbers.

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Attachment 2: Screenshot_2022-05-09_224137.png  229 kB  Uploaded Tue May 10 00:20:18 2022  | Show | Hide all | Show all
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Attachment 4: bhd_platform_291.png  138 kB  Uploaded Tue May 10 00:21:34 2022  | Show | Hide all | Show all
Attachment 5: bhd_platform_394.png  196 kB  Uploaded Tue May 10 00:21:37 2022  | Show | Hide all | Show all
Attachment 6: bhd_platform_402.png  151 kB  Uploaded Tue May 10 00:21:40 2022  | Hide | Hide all | Show all
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