Sloped armor and exponential protection because of it?

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neoconshooter
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Sloped armor and exponential protection because of it?

#1

Post by neoconshooter » 14 Oct 2021, 21:53

In Richard Organowitz, SP? 's books "Design and Development of Armored Fighting Vehicles and others, they all uniformly post a chart that shows both the actual mechanical thickness of the armor when sloped, AND the effective thickness of the slopped armor. In the web page that sent me here, it only shows the mechanical, or actual thickness of sloped armor.
Is there any other program that anyone knows of that computes the "Effective Thickness" of the sloped armor which is always more than the actual-mechanical thickness to be penitrated?

ThatZenoGuy
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Re: Sloped armor and exponential protection because of it?

#2

Post by ThatZenoGuy » 15 Oct 2021, 12:27

The 'effective thickness' of an armor plate is determined by a whole lot of factors, what the plate itself is made of (harder plates IIRC are less effective when sloped), what projectile is attacking the plate, its relative thickness to the diameter of the plate, etc.

A thin sloped plate while logically incredibly strong, might actually not work very well due to overmatching and such.

I don't know if any program can compute every single factor, although I suppose it would be theoretically possible.


Peasant
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Re: Sloped armor and exponential protection because of it?

#3

Post by Peasant » 15 Oct 2021, 14:33

As was said, this is an extremely complicated topic and for now we are able to get only a good enough approximation. Here is some info that might be useful to you:
https://www.forum.axishistory.com/viewt ... ?p=2278138
viewtopic.php?p=2364884#p2364884

Thoddy
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Re: Sloped armor and exponential protection because of it?

#4

Post by Thoddy » 18 Oct 2021, 12:18

on oblique impacts standard "nonderforming" projectiles take a longer way trough plate if the plate behave sufficently ductile than the initial obliquity may indicate. (in this sample impact velocity slightly over ballistic limit)
Ablenkung geschoss a.jpg
red line initial obliquity
blue line avrg obliquity during pentration (notice th S shape)
yellow line exit obliquity
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The distraction appears fairly constant according this chart from "A954868 COMPARATIVE Effectiveness of armor defeating ammunition" for a fairly wide area of obliquities and thicknesses.
a954868 COMPARATIVE Effectiveness of armor defeating ammunition.png
from this data the prolongation of the way corresponds approximately to an additional angle of about 15 degrees.

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in particular the exact route depends on head shape, ductility of plate, lenght of projectile, capped or non capped.
Shorter head shapes tend to take a shorter way trough plate as the center of gravity of projectile is situated more forward and the projectile turns somwhat fewer towards plate on oblique impact then the longer head shape.
Headshape depending oblique performance.png
Headshape depending oblique performance.png (227.28 KiB) Viewed 866 times

Caps of different % weight proportions suppress the tendency of a given projectile to turn at oblique impacts, despite the cap is destroyed on sufficently thick plates
turning moment.jpg
Last edited by Thoddy on 18 Oct 2021, 13:43, edited 1 time in total.
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

Peasant
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Re: Sloped armor and exponential protection because of it?

#5

Post by Peasant » 18 Oct 2021, 13:02

Thoddy wrote:
18 Oct 2021, 12:18
on oblique impacts standard "nonderforming" projectiles take a longer way trough plate if the plate behave sufficently ductile. (in this sample impact velocity slightly over ballistic limit)
Ablenkung geschoss a.jpg
red line initial obliquity
blue line avrg obliquity during pentration (notice th S shape)
yellow line exit obliquity
I'm pretty sure it's the other way around, the entrance is on the left side of the plate, just like with the other photo on that page from the source.

Thoddy
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Re: Sloped armor and exponential protection because of it?

#6

Post by Thoddy » 18 Oct 2021, 17:23

Im not sure.
But your objection makes sense.
I interpreted the larger breakage area on the left side as the exit area.
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

Peasant
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Location: Ukraine

Re: Sloped armor and exponential protection because of it?

#7

Post by Peasant » 18 Oct 2021, 19:06

You can tell which is which by the decreasing diameter of the hole that projectile leaves as it slows down along its trajectory.

Image

Thoddy
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Re: Sloped armor and exponential protection because of it?

#8

Post by Thoddy » 19 Oct 2021, 08:57

ok thx
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

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