Re: Units Was: Re: english schminglish

From: Stirling Westrup (sti@cam.org)
Date: Mon Mar 06 2000 - 12:57:25 MST


Stirling Westrup wrote:

> Spike Jones wrote:
>
> > I wish to propose a metric: tensile strength as a function of density,
> > call it specific strength. Strangely enough, the units come out to the
> > square of velocity, m^2/sec^2:
>
> While I haven't come across it as a concept with its own name, several of
> the sites I've seen talk about strength-to-weight ratios, and so, for
> example, rate graphite whiskers ahead of alumina whiskers, even though the
> alumina has a better measured tensile strength. To use your terminology,
> the graphite has the higher specific strength.

I'm replying to my own reply, since it suddenly occured to me that tensile
 strength per unit density is exactly the WRONG units to use. This would
cause us to use (for example) a 1km thick strand of steel foam in
preference to a 1m thick strand of solid steel, because they had similar
tensile strengths, but one was much less dense. What we want to consider
is tensile-strength per kg.

-- 
 Stirling Westrup  |  Use of the Internet by this poster
 sti@cam.org       |  is not to be construed as a tacit
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                   |  Civilization or its appurtenances.



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