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Early 1980S Armour Comparisons ?


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#41 Hakka

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Posted 12 August 2017 - 2354 PM

Thanks all.



#42 KV7

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Posted 20 August 2017 - 1831 PM

What are some of the 'more advanced interlayer material(s)' ?



#43 EasyE

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Posted 21 August 2017 - 2155 PM

What are some of the 'more advanced interlayer material(s)' ?

 

Good question.. Searching the internet for ballistic elastomers chewed up the greater part of an afternoon..One thing I has suspected was somewhat confirmed though, that the armor designers of the west had a major advantage re: high performance elastic polymers in the late 1980s and 1990s, due to have how common they were in commercial use and manufacturing. To answer your questions, for some reason polycarbonate rings a bell as a interlayer material in the early 1980s.  

 

On another related note, as most know using HHS or UHHS 400-600 BH has issues in NERA arrays. One reason is becasue HHS-UHHS doesn't dissipate the energy of impact well, any impact force of a projectile has a high likelihood of shattering/ cracking the plate. I can't trace this back to the early 1980s but it appears that coatings of elastic (polyurea) and other materials (graphite?), applied to HH-UHHS plates allows for the transfer of energy from the steel into the filler material at a very high efficiency. Think lateral spreading of the impact force across the entire plate.

 

Perhaps this is a clue as to where DU comes into play regarding NERA in HAP. Perhaps a DU alloy plate or mesh within the steel, allows for a HHS plate to efficiently transfer energy and act in a more ductile manner without shattering when impacted.

 

it does appear that NERA arrays that might look similar can have significant performance differences against different threats. Steel types, compression methods, coatings and intralayer materials etc can have massive impacts on effectiveness. 

 

late night ramble over


Edited by EasyE, 21 August 2017 - 2156 PM.


#44 KV7

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Posted 22 August 2017 - 0813 AM

 

What are some of the 'more advanced interlayer material(s)' ?

 

Good question.. Searching the internet for ballistic elastomers chewed up the greater part of an afternoon..One thing I has suspected was somewhat confirmed though, that the armor designers of the west had a major advantage re: high performance elastic polymers in the late 1980s and 1990s, due to have how common they were in commercial use and manufacturing. To answer your questions, for some reason polycarbonate rings a bell as a interlayer material in the early 1980s.  

 

On another related note, as most know using HHS or UHHS 400-600 BH has issues in NERA arrays. One reason is becasue HHS-UHHS doesn't dissipate the energy of impact well, any impact force of a projectile has a high likelihood of shattering/ cracking the plate. I can't trace this back to the early 1980s but it appears that coatings of elastic (polyurea) and other materials (graphite?), applied to HH-UHHS plates allows for the transfer of energy from the steel into the filler material at a very high efficiency. Think lateral spreading of the impact force across the entire plate.

 

Perhaps this is a clue as to where DU comes into play regarding NERA in HAP. Perhaps a DU alloy plate or mesh within the steel, allows for a HHS plate to efficiently transfer energy and act in a more ductile manner without shattering when impacted.

 

it does appear that NERA arrays that might look similar can have significant performance differences against different threats. Steel types, compression methods, coatings and intralayer materials etc can have massive impacts on effectiveness. 

 

late night ramble over

 

If you want to stiffen the plate without adding much mass carbon fibre or graphite reinforced polymer would work well as a backing plate between the steel and elastomer.


Edited by KV7, 22 August 2017 - 0813 AM.


#45 methos

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Posted 26 August 2017 - 1328 PM

There are numerous interlayer materials that should provide better protection than rubber. In Germany Dr. Manfred Held tested a Dyneema liner material as interlayer of a NERA sandwich; he didn't compare it to rubber, but based on the residual penetration values it seems to be superior. There is a document on German tests comparing a fibre-reinforced plastic, an elastomer (might be rubber) and three special (composite) materials made by IBD Deisenroth in a double NERA arrangement. Two tests for each material were made. The worst performing material (the elastomer) left a residual penetration of up to 107 mm, while the IBD-special material in best case left a residual penetration of only 14 mm. +

Chinese research papers mention a combination of rubber and kevlar (as kevlar woven fabric composite), which provides better protection than rubber, despite the higher strength of the interlayer material.

 

There is also a wide variety of energetic materials that can be used for NxRA, that will pretty much always provide superior protection of NERA.

 

As for the DU armor: if you ask ten persons how the DU armor of the Abrams works, you'll get ten answers. It might be a mesh (even though I doubt it), a perforated armor plate, a layer of uranium oxide (i.e. ceramic materials), a thick metal plate or something differnet. The only confirmed armor layout using DU was tested in the UK and consisted of NERA sandwich plates using thin DU layers as front and backplate of each individual sandwich.

5exYuo2.jpg



#46 KV7

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Posted 27 August 2017 - 0046 AM

So it seems the improvement is not from greater plate movement but from simple strengthening of the inter-layer material by adding some reinforcement ?



#47 TTK Ciar

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Posted 27 August 2017 - 1626 PM

That's my interpretation as well. Polycarbonate shouldn't offer any reactive effects at all.

#48 KV7

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Posted 28 August 2017 - 0045 AM

That's my interpretation as well. Polycarbonate shouldn't offer any reactive effects at all.

Polycarbonate is still a fair bit less stiff than steel, it should be able to move a plate somewhat.


Edited by KV7, 28 August 2017 - 0046 AM.


#49 methos

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Posted 28 August 2017 - 0427 AM

It's quite hard to imagine that polycarbonate wouldn't offer any sort of reactive effect, given how much riot gear shields made of polycarbonate bulge and move after impact, and how elastic the material is. Even less elastic materials such as glass have shown a bulging effect when used at certain angles (though in the case of glass this is related to other physical properties of the material).


Edited by methos, 28 August 2017 - 0427 AM.


#50 KV7

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Posted 28 August 2017 - 0451 AM

It's quite hard to imagine that polycarbonate wouldn't offer any sort of reactive effect, given how much riot gear shields made of polycarbonate bulge and move after impact, and how elastic the material is. Even less elastic materials such as glass have shown a bulging effect when used at certain angles (though in the case of glass this is related to other physical properties of the material).

Yeah, and the Poisson ratio at ~ 0.37 is not small.



#51 Hakka

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Posted 08 September 2017 - 0150 AM

Can Gurney equations for sandwiches be used for bulging plates?



#52 KV7

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Posted 08 September 2017 - 1209 PM

Can Gurney equations for sandwiches be used for bulging plates?

 

I cannot see how they could. All the assumptions are grossly violated.


Edited by KV7, 08 September 2017 - 1211 PM.


#53 EasyE

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Posted 08 September 2017 - 2209 PM



As for the DU armor: if you ask ten persons how the DU armor of the Abrams works, you'll get ten answers. It might be a mesh (even though I doubt it), a perforated armor plate, a layer of uranium oxide (i.e. ceramic materials), a thick metal plate or something differnet. The only confirmed armor layout using DU was tested in the UK and consisted of NERA sandwich plates using thin DU layers as front and backplate of each individual sandwich.

5exYuo2.jpg

 

 

Most of the public statements at the time (late 1980s) talked about it being a mesh that was incorporated into high grade steel. This could be more disinformation, there could be a few solutions used in HAP-1. Ie NERA NxERA with HHS plates forged with a DU mesh to give greater density and ballistic properties as well as a ceramic incorporating DU used as part of a backing array.

 

It can't be understated how seriously the Pentagon took the emerging threat of the next generation of soviet anti tank weaponry... It appears that in the early 1980s they learned how ineffective many current armor arrays would be at defeating the monoblock APFSDS in the pipeline. I don't know but I can suspect that testing rounds like the xm833 and xm829 against the early m1 variants; and watching them overpass the armor package with ease had a rather chilling effect. Those who mattered believed strongly that soviet tanks would be shooting a 125mm monoblock DU by the late 1980s and perhaps even a 135mm round by the early 1990s. Threats tend to grow when the budgets do as they did in the early 1980s. The heavy armor project costs something on the order of 2 billion IIRC. At the time the developers felt it would take a decade for the Soviets to be able to manufacture in mass a comparable passive armor package. It does appear they were in large successful with the armor package able to stop Hellfire, Tow-2A and M829A1 rounds during FF incidents in ODS.

 

With the amount of money spent on development, the expected threat and public statements at the time of introduction I suspect that the package is more complex then "DU encased in steel". Whatever it is nearly everything about it is still highly classified 30 years later.



#54 Paul Lakowski

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Posted 09 September 2017 - 1254 PM

Every so often I get the silly notion to try to reopen these armor models and improve them, until I read threads like this.....



#55 Stuart Galbraith

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Posted 09 September 2017 - 1302 PM

:D

 

Nice to see you still pop in Paul. :)



#56 EasyE

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Posted 09 September 2017 - 1623 PM

Every so often I get the silly notion to try to reopen these armor models and improve them, until I read threads like this.....

 

I am starting to think that this thread should be moved out of the  armor scientific area. I work as a scientist and engineer right now. and this much speculation and guessing would get me fired in real life....

 

Having followed this debate for some time, it is amazing how little information has actually leaked out.

 

Chatting with a Canadian Leopard 2 crewman about the hull armor, yielded this   " from what I remember sorta like lots of different layers" :huh:






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