Armoring Vehicles

the-red-scare · 11-21-2021, 08:27 AM

I’m compiling some high-to-ultra-tech armor stats for vehicles. It’s pretty easy to use the armor design rules from Pyramid “Cutting Edge Armor Design” and have a great start. However, I just want to make sure I’ve got a few things right.

1. Ballistic Polymer is explicitly Spectra and Dyneema. Improved Ballistic Polymer is “the latest generation” but doesn’t use the specific naming. Should I assume (for example) present-day Dyneema armor panels for vehicles are improved or regular ballistic polymer?

Or does the manufacturing into rigid panels make them Polymer Composite? And if so, do carbon-fiber vs. Kevlar vs. Dyneema polymer composite have differing DRs unaccounted for in the article?

2. Based on the description, Chobham armor is basically just Improved Ceramic, right? Should it and any others on the table get the “double DR vs. shaped charges” treatment that I guess wasn’t as relevant for personal armor?

Fred Brackin · 11-21-2021, 09:43 AM

Solid panels will be Polymer Composite but thsi is a _class_ of materials and will use an average of DR for multiple specific real world materails.

Chobham is rather more than Improved Ceramic but is too thick to use in personal armor.

FrackingBiscuit · 11-21-2021, 09:49 AM

Ballistic polymer/improved ballistic polymer is a flexible material - it's fabric. It explicitly isn't rigid armor plating. They may be an element in composite armors, but they aren't going to form the rigid hull of a vehicle. The rigid equivalent would be polymer composite.

The armor materials are catch-alls for wide ranges of materials. There are doubtless differences between composites made of different materials, and even in different examples of the same materials. All of that is below the resolution of these armor design rules, and you'll probably drive yourself insane trying to work them out yourself.

Chobham is not ceramic/improved ceramic, it's titanium composite. The description is the closest to chobham out of anything else: "metal matrix composite - alloy reinforced by high-strength ceramic particles or fibers." Improved ceramic is what you would make the insert plates in a plate carrier out of.

Personally, I would treat at least the titanium composite/nanocomposite as laminated. Not sure on polymer/ceramic nanocomposite.

the-red-scare · 11-21-2021, 10:24 AM

Quote:

Originally Posted by FrackingBiscuit

Chobham is not ceramic/improved ceramic, it's titanium composite. The description is the closest to chobham out of anything else: "metal matrix composite - alloy reinforced by high-strength ceramic particles or fibers." Improved ceramic is what you would make the insert plates in a plate carrier out of.

I’m not an expert (hence the questions) but I do know a Chobham is not a metal-matrix composite, which I believe are just barely entering use for armor purposes. It’s ceramic tiles bonded to a backing plate — which is exactly what improved ceramic states. However, I have no doubt it’s rather more sophisticated than the ceramic plates for body armor and surely deserves more DR.

Ulzgoroth · 11-21-2021, 12:42 PM

Quote:

Originally Posted by the-red-scare

I’m not an expert (hence the questions) but I do know a Chobham is not a metal-matrix composite, which I believe are just barely entering use for armor purposes. It’s ceramic tiles bonded to a backing plate — which is exactly what improved ceramic states. However, I have no doubt it’s rather more sophisticated than the ceramic plates for body armor and surely deserves more DR.

You're right that it doesn't fit the "metal matrix composite" description, but it's not as simple as your description either. "it has been described as being composed of ceramic tiles encased within a metal framework and bonded to a backing plate and several elastic layers". Descendant versions may include even more metal framework including a metal front plate. And these composite layers are normally assembled into bulky multi-layer spaced assemblies.

Fred Brackin · 11-21-2021, 12:58 PM

Quote:

Originally Posted by Ulzgoroth

You're right that it doesn't fit the "metal matrix composite" description, but it's not as simple as your description either. "it has been described as being composed of ceramic tiles encased within a metal framework and bonded to a backing plate and several elastic layers". Descendant versions may include even more metal framework including a metal front plate. And these composite layers are normally assembled into bulky multi-layer spaced assemblies.

Even that description leaves out the Depeleted Uranium that's usually mentioned as a component. Someone might hae thought they were being cute by not mentioning that some of the metal was DU.

Ulzgoroth · 11-21-2021, 01:03 PM

Quote:

Originally Posted by Fred Brackin

Even that description leaves out the Depeleted Uranium that's usually mentioned as a component. Someone might hae thought they were being cute by not mentioning that some of the metal was DU.

It's more that they were talking about earlier versions - the DU is a relatively late addition to tank composite armor.

Interestingly it seems somewhat unclear to what extent the ceramic I claimed is really there or when it appeared. The earliest 'chobham' armor look to likely have been only layered and spaced steel and 'plastic' and statements about ceramics inclusion, while very common, tend to be without citation. While the makeup of MBT armor is naturally a matter of military secrecy it surprises me a bit that stuff could stay this obscure for so long.

FrackingBiscuit · 11-21-2021, 08:14 PM

From the wikipedia entry for chobham (https://en.wikipedia.org/wiki/Chobham_armour):

"Although the construction details of the Chobham armour remain a secret, it has been described as being composed of ceramic tiles encased within a metal framework and bonded to a backing plate and several elastic layers."

Ceramic elements in a metal matrix attached to a backing plate. Under "Materials" it's explicitly discussed as a metal matrix composite, and specifically mentions using matrices made of titanium alloy.

Still looks to me that the titanium composite entry is the closest thing to chobham. The improved ceramic (ceramic tiles bonded to a backing plate) sound more advanced versions of the ceramic plates used in body armor. Instead of a monolithic plate that can break up after a few hits, the "improved ceramic" uses many smaller tiles held together by a backing plate to improve multi-hit protection. The breaking up of the ceramic tiles is represented by treating ceramic/improved ceramic as semi-ablative. I've never seen tank armor in GURPS treated as semi-ablative outside of GURPS Ogre for 3E.

Fred Brackin · 11-21-2021, 08:32 PM

Quote:

Originally Posted by FrackingBiscuit

Ceramic elements in a metal matrix attached to a backing plate. Under "Materials" it's explicitly discussed as a metal matrix composite, and specifically mentions using matrices made of titanium alloy.

This may not be an area to trust Wikipedia but in any event "metal and ceramic sandwiched together" is _not_ what Gurps means by "metal matrix composite". Chobham in Gurps Vehicles was described as "TL7 Advanced Laminate". There was no personal armor equivalent to Chobham. It would ahve been too thick to wear.

"Metal matrix composites" were hypothetical higher TL materials with super-strong fibers embedded in a metal alloy rather than just sandwiched. Sort of the way "fiberglass" is glass fibers in a resin matrix.

FrackingBiscuit · 11-22-2021, 11:37 AM

My understanding of a metal matrix composite is that it's a continuous matrix made of metal containing additional elements of another material. Most describe whiskers or fibers, but every source I look at outside wikipedia doesn't limit them to just that. I don't see how that doesn't describe a titanium matrix containing ceramic tiles. Chobham uses exactly that, sandwiched between steel plates to make a laminate, probably with other elements like depleted uranium.

MMCs also seem to date back to the 1960s, and were used in some cars in the 80s/90s (and possibly in the F-16 in the 70s?). They don't sound like "hypothetical higher TL materials" to me.

---

For what it's worth, The_Ryujin over at GURB did some research in armor materials a while back: https://gurb3d6.blogspot.com/2016/08...armor-and.html

He described early Chobham as a "light composite" with a weight modifier of 0.25, and later versions of Chobham as a "composite laminate" with a weight modifier of 0.19. Cutting Edge Armor Design puts titanium composite's weight modifier at 0.2 and improved ceramic's as 0.15. GURPS Vehicles puts expensive TL7 laminate armor at 0.25, and advanced TL7 laminate at 0.15. GURPS vehicles even describes "the whole sometimes reinforced with a metallic mesh," (p. 22). The descriptions sounds closer than "ceramics with a metal backing or polymer casing."

Obviously no description is going to be a perfect fit because 1. the exact composition of Chobham isn't publicly known, and furthermore has changed over time, and 2. the materials in pyramid are meant to be broad categories with brief descriptions. Naturally there's ambiguity, but I'm really not seeing how improved ceramic is a closer fit to chobham than titanium composite, or how you can categorically say that Pyramid's "titanium composite" can't be Chobham.

11-21-2021, 08:27 AM	#1
the-red-scare Join Date: Sep 2014	Armoring Vehicles I’m compiling some high-to-ultra-tech armor stats for vehicles. It’s pretty easy to use the armor design rules from Pyramid “Cutting Edge Armor Design” and have a great start. However, I just want to make sure I’ve got a few things right. 1. Ballistic Polymer is explicitly Spectra and Dyneema. Improved Ballistic Polymer is “the latest generation” but doesn’t use the specific naming. Should I assume (for example) present-day Dyneema armor panels for vehicles are improved or regular ballistic polymer? Or does the manufacturing into rigid panels make them Polymer Composite? And if so, do carbon-fiber vs. Kevlar vs. Dyneema polymer composite have differing DRs unaccounted for in the article? 2. Based on the description, Chobham armor is basically just Improved Ceramic, right? Should it and any others on the table get the “double DR vs. shaped charges” treatment that I guess wasn’t as relevant for personal armor?

11-21-2021, 09:43 AM	#2
Fred Brackin Join Date: Aug 2007	Re: Armoring Vehicles Solid panels will be Polymer Composite but thsi is a _class_ of materials and will use an average of DR for multiple specific real world materails. Chobham is rather more than Improved Ceramic but is too thick to use in personal armor. __________________ Fred Brackin

11-21-2021, 09:49 AM	#3
FrackingBiscuit Join Date: Oct 2019	Re: Armoring Vehicles Ballistic polymer/improved ballistic polymer is a flexible material - it's fabric. It explicitly isn't rigid armor plating. They may be an element in composite armors, but they aren't going to form the rigid hull of a vehicle. The rigid equivalent would be polymer composite. The armor materials are catch-alls for wide ranges of materials. There are doubtless differences between composites made of different materials, and even in different examples of the same materials. All of that is below the resolution of these armor design rules, and you'll probably drive yourself insane trying to work them out yourself. Chobham is not ceramic/improved ceramic, it's titanium composite. The description is the closest to chobham out of anything else: "metal matrix composite - alloy reinforced by high-strength ceramic particles or fibers." Improved ceramic is what you would make the insert plates in a plate carrier out of. Personally, I would treat at least the titanium composite/nanocomposite as laminated. Not sure on polymer/ceramic nanocomposite.

11-21-2021, 08:14 PM	#8
FrackingBiscuit Join Date: Oct 2019	Re: Armoring Vehicles From the wikipedia entry for chobham (https://en.wikipedia.org/wiki/Chobham_armour): "Although the construction details of the Chobham armour remain a secret, it has been described as being composed of ceramic tiles encased within a metal framework and bonded to a backing plate and several elastic layers." Ceramic elements in a metal matrix attached to a backing plate. Under "Materials" it's explicitly discussed as a metal matrix composite, and specifically mentions using matrices made of titanium alloy. Still looks to me that the titanium composite entry is the closest thing to chobham. The improved ceramic (ceramic tiles bonded to a backing plate) sound more advanced versions of the ceramic plates used in body armor. Instead of a monolithic plate that can break up after a few hits, the "improved ceramic" uses many smaller tiles held together by a backing plate to improve multi-hit protection. The breaking up of the ceramic tiles is represented by treating ceramic/improved ceramic as semi-ablative. I've never seen tank armor in GURPS treated as semi-ablative outside of GURPS Ogre for 3E. Last edited by FrackingBiscuit; 11-21-2021 at 08:18 PM.

11-22-2021, 11:37 AM	#10
FrackingBiscuit Join Date: Oct 2019	Re: Armoring Vehicles My understanding of a metal matrix composite is that it's a continuous matrix made of metal containing additional elements of another material. Most describe whiskers or fibers, but every source I look at outside wikipedia doesn't limit them to just that. I don't see how that doesn't describe a titanium matrix containing ceramic tiles. Chobham uses exactly that, sandwiched between steel plates to make a laminate, probably with other elements like depleted uranium. MMCs also seem to date back to the 1960s, and were used in some cars in the 80s/90s (and possibly in the F-16 in the 70s?). They don't sound like "hypothetical higher TL materials" to me. --- For what it's worth, The_Ryujin over at GURB did some research in armor materials a while back: https://gurb3d6.blogspot.com/2016/08...armor-and.html He described early Chobham as a "light composite" with a weight modifier of 0.25, and later versions of Chobham as a "composite laminate" with a weight modifier of 0.19. Cutting Edge Armor Design puts titanium composite's weight modifier at 0.2 and improved ceramic's as 0.15. GURPS Vehicles puts expensive TL7 laminate armor at 0.25, and advanced TL7 laminate at 0.15. GURPS vehicles even describes "the whole sometimes reinforced with a metallic mesh," (p. 22). The descriptions sounds closer than "ceramics with a metal backing or polymer casing." Obviously no description is going to be a perfect fit because 1. the exact composition of Chobham isn't publicly known, and furthermore has changed over time, and 2. the materials in pyramid are meant to be broad categories with brief descriptions. Naturally there's ambiguity, but I'm really not seeing how improved ceramic is a closer fit to chobham than titanium composite, or how you can categorically say that Pyramid's "titanium composite" can't be Chobham.