04-16-2014, 10:05 PM | #1 |
Join Date: Feb 2007
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Physics of a tank impact...
Suppose hypothetically that a one kilogram (or close enough) piece of dense rock (like basalt or granite) slammed into the main-body armor of a modern-day battletank at a velocity of about 740 meters/sec (never mind how the situation arose).
What exactly is likely to happen? Is it going to penetrate, or tear a gash in the armor, or will it shatter and a lot of the energy be carried away? I'm sure it would disable the main gun if it struck that, but what about the main body armor? Or the turrent armor, or the treads? (I'm pretty sure it would be Very Bad Indeed for the treads or motive machinery if it hit them, actually.) |
04-16-2014, 10:19 PM | #2 | |
Join Date: Feb 2005
Location: Berkeley, CA
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Re: Physics of a tank impact...
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So, most likely, it damages the paint job. I doubt it would even go through side armor. |
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04-16-2014, 10:59 PM | #3 | |
Doctor of GURPS Ballistics
Join Date: Sep 2004
Location: Lakeville, MN
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Re: Physics of a tank impact...
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04-16-2014, 11:25 PM | #4 |
Join Date: Nov 2004
Location: The plutonium rich regions of Washington State
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Re: Physics of a tank impact...
Rock is relatively low density and is not very strong compared to armor. At ~700 m/s, dynamic pressure will not be enough to plastically deform even steel, never mind advanced modern armors. My best guess is that the rock shatters and the tank is unharmed. If it hits someplace with a thickness less than the rock diameter, it might dent or crack that section.
Luke |
04-17-2014, 03:52 AM | #5 | |
Join Date: Apr 2005
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Re: Physics of a tank impact...
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In fact, a single strike from that rock will probably have no effect other than scratching the paint. If you hit the lens of an optic, you might impair it (Cracked external lens), and you might damage some of the external features (Such as the external MGs). Chances of knocking out a track or damaging the engine is probably negligible, particularly given rock's low density compared to a metal round. Compared to the kinetic rounds that are a threat to a tank, that thing is lightweight, slow, low-density, has a high cross-section, and is fragile (The rock is most likely going to shatter on impact, making its already-poor performance even worse). |
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04-17-2014, 04:19 AM | #6 | |
Banned
Join Date: Jun 2005
Location: Bristol
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Re: Physics of a tank impact...
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So it must have come from space to have a lump of rock go super sonic. Rocks that have no aerodynamic shape will not go super sonic. The sound barrier would break it apart. |
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04-17-2014, 06:24 AM | #7 | |
Doctor of GURPS Ballistics
Join Date: Sep 2004
Location: Lakeville, MN
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Re: Physics of a tank impact...
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I gave it the armor divisor because of the brittle-and-shatter thing Luke mentioned above.
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04-17-2014, 09:07 AM | #8 |
Join Date: Jun 2007
Location: Kansas City, MO
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Re: Physics of a tank impact...
And Douglas Cole has a pretty good ballistic formula, so that should be about right.
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04-17-2014, 10:41 AM | #9 |
Join Date: Jun 2006
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Re: Physics of a tank impact...
That last bit not really. Once you are up in the supersonic range how fragile a missile is doesn't matter so much - in a sense it doesn't have enough time to shatter, it's through the target before a stress that would break it apart can propagate through it. Note that our many of our anti-tank penetrators are actually liquids (molten metal jets) at the moment they actually hit the armor.
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04-17-2014, 10:42 AM | #10 |
Join Date: Aug 2007
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Re: Physics of a tank impact...
It's low density too. Better than wood but less than half of steel or 1.8th of DU.
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Fred Brackin |
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