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"Interesting" info about Depleted Uranium penetrators/HEAT rounds

"Interesting" info about Depleted Uranium penetrators/HEAT rounds - Physics Forum

"Interesting" info about Depleted Uranium penetrators/HEAT rounds - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 12-13-2004, 11:15 AM
tw
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds



> tw wrote:


Have you checked those links Mikey? Now do you realise you were incorrect to
say a "DU is referred to as a heat round"?

I see you confused HEAT (high explosive anti tank) and heat as in thermal
energy. However, a "heat round" means one thing and one thing only WRT
anti-tank weaponry.



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?

<snip>


1) What chemical reaction is that?

2)I certainly never claimed that heat woudl not be produced! Please cite
where I did. I merely claimed a solid DU round uses kinetic energy to
defeeat armour, it does not "melt through the mettle (sic)". I merely
claimed a DU round was seperate and distinct from a HEAT (high explosive
anti tank) round, not least because it contains no explosive. Apologies if I
confused you by not always using upper case for "HEAT", but "heat round
"means only one thing in terms of tank ammunition. Seeing as you were
attempting to lecture me on what a DU penetrator was, I assumed you woudl
know these basic terms.


What?


Head?


I have never denied that heat woudl be produced by the imapct, merely that
it is not heat which defeats the armour when it is hit by a solid DU
penetrator, any more than it is heat which causes a dart to stick in a
dartboard...


Well, he who laughs last and all that...



Is this supposed to be humour?



Please learn the distinction between the acronym HEAT and heat.


Already done. Crossposted to a militarygroup too, for good measure (though
it is a moderated one)


Already done. For anyone in the military group who is interested, Mikey has
been claiming for a year or so now that a DU penetrator (e.g. APFSDS) is a
"sort of HEAT round" which "melts through the mettle (sic)" of whatever
metallic object it is fired at. My osition is that e.g. APFSDS rounds uses
kinetic energy to penetrate and are very different from HEAT. I would accept
"melts through the mettle (sic)" as a slightly innacurate term for what a
shaped charge does, but that's beside the point.



I have. I even provided you with links to descriptions of tungsten/DU
penetrator rounds and HEAT rounds. You have apparently chosen to ignore
them.


HEAT means High Explosive, Anti-Tank. It referes to a type of ammunition .
how many more times?



What the..? Whenever did I say this was the case? YOu are confusing the
acronym HEAT with heat again. Even so, heat (as in thermal energy) is NOT
what defeats the armour when it is hit by a solid DU (or tungsten)
penetrator, kinetic energy does. I assmue some of the is kinetic energy is
converted to thermal energy on impact, I never said it wasn't.



Please indicate how that is supposed to be proof of me "supporting
terrorism"?!


Apparently so...




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  #2  
Old 12-14-2004, 07:31 AM
Paul Saccani
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds

On Mon, 13 Dec 2004 12:15:28 +0100, "tw" <[Only registered users see links. ]> wrote:


Long rod penetrators do indeed melt the armour in their path, and their tips
ablate. The combination of molten metal etc... flows rapidly around the
penetrator as it goes through, like mud around a drill string. So it is not
like punching a hole in the manner of say, a familiar paper punch.

"least, that's as far I know.
cheers,

Paul Saccani
Newman West Australia
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  #3  
Old 12-14-2004, 09:29 AM
Carey Sublette
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds


"Paul Saccani" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...

The flowing of the metal is more likely simply the effect of exceeding the
yield strength of the metal in front of the penetrator tip. The tip, I'd
say, "erodes" not "ablates".

This is also true of HEAT rounds, the metal particle stream (not liquid or
vapor) acting basically like a long rod penetrator (or contrariwise, the
long rod penetrator is a much like a fixed version of a HEAT jet).

Carey Sublette

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  #4  
Old 12-14-2004, 10:12 AM
tw
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds


"Carey Sublette" <[Only registered users see links. ]> wrote in message
news:9oyvd.10828$[Only registered users see links. ].pas.earthl ink.net...
concentration
such
the

I prefer this answer :-) So it does "pierce" rather than "melt"..


So even a shaped charge doesn't "melt its way through the mettle (sic)" ?




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  #5  
Old 12-14-2004, 10:25 AM
tw
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds


"Paul Saccani" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
its
primary
speed
of
of
such
kinetic
tips

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


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


punch.

This artice, at least seems to identify kinetic energy as the main player:








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  #6  
Old 12-14-2004, 10:28 AM
tw
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds

oops.. let's try that again.

"Paul Saccani" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
its
primary
speed
of
of
such
kinetic
tips

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),


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


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):

[Only registered users see links. ]

"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."




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  #7  
Old 12-14-2004, 09:13 PM
Colin Campbell
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds

On Tue, 14 Dec 2004 15:31:22 +0800, Paul Saccani
<[Only registered users see links. ]> wrote:



The metal does not melt. The impact energies are so high that the
physics of solid objects no longer apply and the materials behave as a
liquid.




--
There can be no triumph without loss.
No victory without suffering.
No freedom without sacrifice.
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  #8  
Old 12-15-2004, 12:16 AM
Brian Trosko
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds

In sci.military.moderated Paul Saccani <[Only registered users see links. ]> wrote:


Naw, there's no melting involved. There's fluid/plastic deformation, but
that's the result of applying enormous pressure to a small area of the
armor, not the result of dumping enough energy into it to bring about a
phase change.

It's pretty much like pushing a screwdriver through a beer can, but on a
much shorter timescale.
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  #9  
Old 12-15-2004, 04:09 AM
Paul Saccani
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Default "Interesting" info about Depleted Uranium penetrators/HEAT rounds

G'day Carey,

On Tue, 14 Dec 2004 09:29:41 GMT, "Carey Sublette" <[Only registered users see links. ]>
wrote:


It is a combination of effects. What you say is partially true. However, the
molten metal etc.. does act like "mud" to transport the material out, which
includes solid particles etc...


If the tip erodes, you are saying the process happens gradually. The two words
are almost, but not quite synonyms. Ablation does not imply *gradual* removal
of material. Thus ablation is the correct term for any rapidly occurring
process which removes (ablates) material, and erosion is not. However, by all
means call it erosion if you wish, for I am sure no one will misunderstand that
we are talking about a rapid process in this context.


Well, they certainly both rely on pressure. I'd tend to think that the HEAT jet
after penetration is going to be more unpleasant than the spall etc... from a
long rod. Or to put it another way, crew chances of survival of penetration
from a long rod (even pyroporphric DU) are better. Of course, the key is
whether or not that penetration occurs in the first place.


Follow ups to sci.military.moderated please.


cheers,

Paul Saccani
Newman West Australia
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  #10  
Old 12-15-2004, 07:03 AM
Repeating Rifle
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Default "Interesting" info about Depleted Uranium penetrators/HEATrounds

in article [Only registered users see links. ], Paul Saccani at
[Only registered users see links. ] wrote on 12/13/04 11:31 PM:

Just to keep everyone honest, do not confuse *kinetic energy* with
*momentum*. Momentum is "a product of its weight [mass rather than weight]
and speed" Kinetic energy is the product of mass and the square of the speed
(divided by two). Thus, melting, which can be very local is greatly enhanced
by additional speed. That is, double the speed, quadruple the amount of melt
on a very simple model.

Bill
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