Re: [ATM] Flex Software

["Richard F.L.R. Snashall" <rflrs@rcn.com>]

Mark Holm wrote:

>The modulus, aka Young's modulus is probably the most important number.
> Modulus is about 6100 KgF/mm^2 for plate glass, and 6400 for Pyrex.
>That difference is probably within the planned adjustment range.
>
>Fused silica and Zerodur are a bit farther out at 7400 and 9100.
>
>Remember that the stiffness of a plate varies as the cube of the
>thickness.  Thus the maximum ratio, Zerodur to plate is equivalent to a
>thickness change of
>
>	100 * (((9100 / 6100) ^ (1/3)) - 1)  = 14%
>  
>
Looking in my glass catalog, glass PSK54 has a "modulus of elasticity (E)"
[I've heard that that is the same as Young's modulus] of 52000 N/mm^2.
OK, so what is a KgF and where did I get the extra power of 10... Is this
something to do with 9.8 M/sec^2, or something?

P.S.: Yes, I did not pick PSK54 at random...;-)
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