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Predator117
03-21-2007, 08:57 PM
Ok. this is an issue that I've been dealing with for a couple of days.

which one of these would sustain heavy firepower better:

a 40 lb metal breast plate
or a 8 lb kevlar vest..?
both which are about equal in thickness(1/4 inch roughly)

or would they be about equal, which is what I think because I've read that kevlar is 5 times more durable than steel, when equal in weight, however. and in this case, the steel breastplate is exactly 5 times heavier. (40/8 = 5)
but I could be wrong. could anybody be of any assistance..?

thespianphryne
03-21-2007, 09:20 PM
Describe the firepower and the ammunition which the armor is supposed to be protecting against. It's not just a question of weight or thickness but also of the number of layers.


-Das

Deskad
03-21-2007, 09:29 PM
The question is incorrect at its root. Kevlar doesen't work like steel does. It's a weave, not a solid plate.

And if you're asking as to which would hold bullets from say, an assault rifle better;

1. A quarter inch thick plate of steel.

or

2. A quarter inch thick weave of Kevlar. Assuming it's something like triple weave[about standard for a flack vest.

Well, the answer is, neither one would even slow the bullet down.

As said, kevlar strands are pound for pound 5 times as strong as steel when it comes to tensile strength, , and can stop a handgun bullet [9x18], which steel just can't do at that thickness, as it relies on hardness to stop the kinetic effetct, but against something like a rifle, not much good. And completely useless against a knife.

Modern body armor, at least the one used now, relies on ceramic plates to stop bullets, inserted into the kevlar.

Newer armor are a titanium kevlra interweave scale patter, ie dragon-skin. Or, like the Russian prototype just coming out, a new type of substance that works on locking molecule pattern, otherwise known as liquid armor.

Predator117
03-22-2007, 05:58 AM
Describe the firepower and the ammunition which the armor is supposed to be protecting against. It's not just a question of weight or thickness but also of the number of layers.


-Das

ok, its over 50+ bullets from a 9mm pistol. and its like the metal breast plate on V for Vendetta vs a light kevlar vest.

Predator117
03-22-2007, 06:05 AM
The question is incorrect at its root. Kevlar doesen't work like steel does. It's a weave, not a solid plate.

And if you're asking as to which would hold bullets from say, an assault rifle better;

1. A quarter inch thick plate of steel.

or

2. A quarter inch thick weave of Kevlar. Assuming it's something like triple weave[about standard for a flack vest.

Well, the answer is, neither one would even slow the bullet down.

As said, kevlar strands are pound for pound 5 times as strong as steel when it comes to tensile strength, , and can stop a handgun bullet [9x18], which steel just can't do at that thickness, as it relies on hardness to stop the kinetic effetct, but against something like a rifle, not much good. And completely useless against a knife.

Modern body armor, at least the one used now, relies on ceramic plates to stop bullets, inserted into the kevlar.

Newer armor are a titanium kevlra interweave scale patter, ie dragon-skin. Or, like the Russian prototype just coming out, a new type of substance that works on locking molecule pattern, otherwise known as liquid armor.

so would tensile strength have anything to do w/ stopping bullets, or no?
and ur saying 1/4" thick solid steel wouldnt stop a knife..?? :confused:

Tages
03-22-2007, 06:09 AM
There is no such thing as a truly "bullet-proof" vest. A more accurate description would be "bullet-RESISTANT."

And no, assuming it's high-quality steel and hasn't been intentionally weakened (like heating it red and then quickly cooling it off), a knife will not go through a quarter inch of steel.

Predator117
03-22-2007, 06:13 AM
There is no such thing as a truly "bullet-proof" vest. A more accurate description would be "bullet-RESISTANT."

And no, assuming it's high-quality steel and hasn't been intentionally weakened (like heating it red and then quickly cooling it off), a knife will not go through a quarter inch of steel.

well Ive already known that kevlar wont stop rifles, because of their high velocity, but how thick would a piece of steel have to be to stop a 9mm pistol round..?

Predator117
03-22-2007, 04:06 PM
any other ideas...?

Mac Danny
03-22-2007, 07:05 PM
And completely useless against a knife.

The slow blade penetrates the shield.

http://images.amazon.com/images/G/01/dvd/dvd-dune-sting.jpg

Deskad
03-22-2007, 07:18 PM
Um... I guess I phrased it badly.. what I was saying is that a kevlar vest is pretty much useless against a knife.

Of course, a metal plate is very useful against bladed weapons. This concept has existed for thousands of years, it's called a shield.

Mac Danny
03-23-2007, 05:47 AM
Um... I guess I phrased it badly.. what I was saying is that a kevlar vest is pretty much useless against a knife.

Of course, a metal plate is very useful against bladed weapons. This concept has existed for thousands of years, it's called a shield.

Nah, I'm just F'n around. It's what the statement reminded me of.

BlairH
03-23-2007, 06:11 AM
You planning on getting shot or something?

Mac Danny
03-23-2007, 06:39 AM
You planning on getting shot or something?

What you should say is.. "Need someone to Shoot you?"

Agent Helix
03-23-2007, 06:45 AM
Wait a minute.

Kevlar? Metal chestplates?

What kind of sissy-ass Yautja are you, anyway?

HomerJay
03-23-2007, 10:13 AM
What about titanium laminated with kevlar?

http://img.photobucket.com/albums/v655/HomerJay64/robocop2.jpg

Deskad
03-23-2007, 10:53 AM
What about titanium laminated with kevlar?

http://img.photobucket.com/albums/v655/HomerJay64/robocop2.jpg

Titanium scales laminated with Kevlar, put into a scale/skin type pattern that can also distribute anergy to a larger area.

It's called DragonSkin, there's even a Future Weapons episode about it.