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Old 12-21-2014, 02:57 AM   #11
Anthony
 
Join Date: Feb 2005
Location: Berkeley, CA
Default Re: Linear shaped charge to cut through DR 1900?

Hey, found some [url=http://www.aesys.biz/wp-content/uploads/data-sheet_13-224_liner-shaped-charge.pdf]real numbers[/url. A copper linear shaped charge with a weight of 0.5 lb/ft has a penetration (in an unstated material which I will guess is steel) of 0.7 inches, or about DR 50. The heaviest in there has a penetration of 3 inches, or DR 210, with a weight of 4.3 lb. We want 9 times that penetration, so based on the scaling law given (which appears to be a simplification, as the chart doesn't quite match), we multiply weight by 81 and wind up with a weight of ~350 lb/ft. We'll reduce that by 75% for better explosives, and by 50% for better penetration tech, and we wind up with a weight of around 45 lb/ft.

However, bear in mind that a significant fraction of the explosive energy will go into melted chunks of armor spraying through the other side of the armor, which will make a gigantic mess. This is only a problem if you want things intact, of course, but if you don't want it at least semi-intact, why are you boarding it at all?
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Old 12-21-2014, 04:22 PM   #12
BraselC5048
 
Join Date: Oct 2012
Default Re: Linear shaped charge to cut through DR 1900?

Quote:
Originally Posted by Anthony View Post
Hey, found some [url=http://www.aesys.biz/wp-content/uploads/data-sheet_13-224_liner-shaped-charge.pdf]real numbers[/url. A copper linear shaped charge with a weight of 0.5 lb/ft has a penetration (in an unstated material which I will guess is steel) of 0.7 inches, or about DR 50. The heaviest in there has a penetration of 3 inches, or DR 210, with a weight of 4.3 lb. We want 9 times that penetration, so based on the scaling law given (which appears to be a simplification, as the chart doesn't quite match), we multiply weight by 81 and wind up with a weight of ~350 lb/ft. We'll reduce that by 75% for better explosives, and by 50% for better penetration tech, and we wind up with a weight of around 45 lb/ft.
Thanks. Nice find.

Quote:
Originally Posted by Anthony View Post
However, bear in mind that a significant fraction of the explosive energy will go into melted chunks of armor spraying through the other side of the armor, which will make a gigantic mess. This is only a problem if you want things intact, of course, but if you don't want it at least semi-intact, why are you boarding it at all?
My current ship is a heavy cruiser. It over 380 feet long, has 8 decks, and has a beam for most of its length of 90 feet. Considering every single wall is DR 75, I don't think it will cause all that much damage (or any) past the compartment behind the airlock. If the inner airlock door is closed, then nothing past that. (DR 125, due solely to structural considerations - I went and ran the real-world engineering numbers for most of the ship's structure, and since as a door it lacks a bracing cross beam that bulkheads have, it has to be thicker to make up for it.)

Any interest on the forum for gaming session recaps for a session where my character won the medal of honor?
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armor divisor, explosive, explosives required, shaped charge, weapon design

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