[ATM] Re: Second Thoughts on Mirror Support

[mikell at optonline.net (Michael Lindner)]

On Wednesday 04 February 2004 10:17 pm, Mark Holm wrote:
> For small amounts of compression, compressive
> modulus is often pretty close to tensile modulus, so it is probably safe
> to  use that number, which is  89.9 ksi  Which means 89900psi.

Hmmm...then I think something's fishy. If I use a compressive modulus of 
89.9kpsi, then I need a force of 103 pounds just to compress that silicone 
pad 0.007". That seems excessive, as I think plopping 100 pounds on a 1" 
diameter silicone pad would do more than compress it by 1/150".  Of course I 
could be wrong...I'm not that familiar with these constants...

Clear skies.
-- 
Michael Lindner
http://www.starastronomy.org *** http://home.att.net/~mikel
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