Re: "Interesting" info about Depleted Uranium penetrators/HEAT rounds

From: tw (no_at_no.com)
Date: 12/14/04 

To: sci-military-moderated@moderators.isc.org
Date: Tue, 14 Dec 2004 11:28:42 +0100

oops.. let's try that again.

"Paul Saccani" <traptinnedspicedham@hotmail.com> wrote in message
news:9d5tr018r5jegm4kj9cdgvds531d8kbaat@4ax.com...
> On Mon, 13 Dec 2004 12:15:28 +0100, "tw" <no@no.com> wrote:
>
> >OK, done. To the denizens of sci.physics. Does an anti tank shell which
> >consistes of a tungsten penetrator use kinetic energy (i.e. a product of
its
> >weight and speed) to penetrate armour, or is the chemical definition of
> >"kinetic" applicable here instead? Myself, I am 100% sure it is the
primary
> >definition of kinetics, i.e. it is the combination of the projectiles
speed
> >and weight (but mostly speed) that applies here, rather than "The branch
of
> >chemistry that is concerned with the rates of change in the concentration
of
> >reactants in a chemical reaction"
> >
> >Whilst no one is disputing considerably thermal energy is produced in
such
> >an event, the solid DU round punches through the armour due to its
kinetic
> >energy, it does not "melt through the mettle (sic)" due to some chemical
> >reaction. true or false?
>
> Long rod penetrators do indeed melt the armour in their path, and their
tips
> ablate.

Ta for that, but I was under the impression that they tended to "punch"
though
then vapourise (igniting on the other side due to the pyrophoric nature of
DU),

> The combination of molten metal etc... flows rapidly around the
> penetrator as it goes through, like mud around a drill string.

So the penetrator itself remains essentially solid but bits melt around the
edge of it?

> So it is not like punching a hole in the manner of say, a familiar
paperpunch.

This artice, at least seems to identify kinetic energy as the main
layer -"punching" rather than "melting" (I'm not sure what the implications
are in a physics context):

http://www.army-technology.com/contractors/ammunition/apfsds.htm

"By using very dense materials in the sub-projectile the stored kinetic
energy is magnified greatly. The terminal effect of the sub-projectile
striking the target sees huge kinetic energy release. In miliseconds the
sub-projectile punches through the target armour, instantaneously generating
massive heat and pressure. As the long rod penetrator enters the vehicle
friction with the armour plate creates burning incandescent spall which
sprays the interior. The burning spall has an explosive effect."

>
> "least, that's as far I know.
> cheers,
>
> Paul Saccani
> Newman West Australia