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Vibration isolation mounts

Vibration isolation mounts

Vibration isolation mounts

(OP)
Looking to design a vibration isolation mount for an electrical box on a piece of space hardware.  Thinking of a 4 point connection using 3/8 shoulder bolts (NAS1160?) and rubber bushings (buna-n?).  Box weight is approx 50 lbs with connection in primary shear.  If I'm heading down the right track I need to find the bushings.  Any ideas?

RE: Vibration isolation mounts

"a piece of space hardware" -for what agency or end user?  What duration?  Buna-N won't last long in LEO; do you care?  Does the end user care if flakes of rubber and/or volatile materials (oil) are floating around inside his spacecraft, obscuring lenses, shorting exposed wires, and whatnot?  What static g levels are your design requirements, and what random vibration spectrum are you trying to dampen?  You can contact Lord Aerospace, they have a lot of experience designing space-rated (low outgassing, rad-hard) shock and vib isolation mounts.

RE: Vibration isolation mounts

(OP)
The space hardware is the aft skirt of the Shuttle Solid Rocket Booster.  This is an external application with debris being the only issue.  I am not concerned with the loads/enviroments at this time....just looking for different ideas on mounts.  Thanks for the contact...I'll check it out.

RE: Vibration isolation mounts

DOUGKEUNEKE... btrueblood has a very important point... ignore it at your own peril.

You may be too young to remember the Challanger accident. The rubber O-rings on the booster "hardened" in the extreme cold of the January 1986 freeze and the presence of the the LOX tank. Subsequently, the damaged primary and back-up rings at one joint failed to hold pressure when the RH booster ignited... and began leaking hot-gasses immediately: ~77 seconds later the flight was "over".

Elastomer materials "stiffen" when temps fall... and "soften" as temps rise... resulting in highly variable mechanical properties... not-the-least being deformation/load and dampening characteristics... and all the other factors noted by btrueblood.

Have You looked at wire-rope springs/isolators?

Regards, Wil Taylor

RE: Vibration isolation mounts

I'd like to second wktaylor & btrueblood.  I remember January 28, 1986 that was my 20th birthday.  

I worked a space program at a large US defense company and I remember they were extremely paranoid about using Elastomer material for any damping, shock or vib.  The reason being they had a satellite that had solar array snubbers that had outgassed which prevented them from being deployed.

Here are a couple of links for Barry Controls.  I've used some of their mechanical isolators for electronic equipment.

http://www.barrycontrols.com/

http://www.stopchoc.co.uk/offshore_avms.html

http://www.stopchoc.co.uk/anti_vibration_products.html

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