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Early 1980S Armour Comparisons ?


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EasyE, the US Army had underestimated the capabilities of the Soviet tank guns by quite a bit, that's why the M1 Abrams turned out to be rather under-armored for its time. To quote the 1982 report from where I took the values (400 mm RHA vs KE, 800 mm RHA vs CE):

"The study that recommended development of the M1 Abrams MBT stated that the T-72 would have a 115mm main gun capable of penetrating 147mm RHA at 60° obliquity at 1,000M and 120mm of RHA at 60° obliquity at 2,000M. In justifying the predicted retention of the 115mm gun (although a caveat was included that other reported calibers might include 122, 125, and 130mm), ITAC stated that the penetration design could be improved. The gun chamber volume and tube length could also be increased. In fact, the weapon developed was a 125mm gun capable of penetrating 161mm RHA at 60° obliquity at 2,000M. Again in 1981, it was forecast that the NST (T-80) and FST (T-80 FO) would retain the 125mm gun, but have an improved projectile and increased chamber pressure."

 

The US Army understimated the Soviet tank development and assumed that the 115 mm gun would remain the main threat for tanks. NATO at the time (at least the USA and West-Germany) did still believe that the T-80 would enter service somewhere during the mid-1980s. Even in 1982, the penetration power of the Soviet APFSDS was still underestimated. Considering what the US believed to be the state of Soviet tank development, demanding protection only against 115 mm APFSDS from 800 m distance seemed to be a good idea; unfortunately NATO/the United States didn't knew enough about Soviet weapons at the time, in case of a war in 1980, NATO would have been suprised quite a lot. Even in 1982 penetration levels were far below of what Soviet APFSDS was capable to do.

 

From what I know, the "perforated armor" of the Leopard 2 seems to be a myth spawned by some internet users. I have not seen any German language source suggesting anything, no official document, no mention in a book and also no patent. German armor seems to be NERA mainly, but might follow a different layout compared to US/British armor based on what I have heard/read. The Abrams' armor shouldn't really provide much greater protection against a BM-26 APFSDS or similar designs; in order to be effective against APFSDS ammo, NERA requires thick plates and/or high-hardness steel as material. The NERA array used on the early Abrams, at least at the places for which we have data, seems to be based around very thin steel plates only. This such provide no additional protection over homogenous or spaced steel plates according to literature.

 

 

 

 

That I don't dispute. I am not referring to the guns really but being very specific about ammunition design. One things that has become very clear to me during my study of this topic is that against complex armor arrays the term APFSDS is far from all encompassing so statements from the literature unless specified are not totally useful in this context. Rounds like the BM-26 and the M883 have different penetration mechanics against steel armor, similar performance. When it comes to the penetration mechanics against spaced arrays and complex arrays with NERA, the comprise in the design of early 125mm ammo start to result in a very sharp drop off in performance. Bm-22/26 don't perform well against spaced armor arrays, so there is little reason to think that a ~700mm array with 4 NERA plates "could" not be effective. Even thin plates will introduce asymmetric loading in a projectile with multiple components of different densities and dimensions. The steel body after some penetration acts as a support to the Tungsten slugs, in effect ensuring they have a lateral pathway through the rest of the armor. Against sandwich type arrays (like the ones the Soviets assumed would be the armor layout of western designs this still works reasonably well.

 

Still depends on a great deal of unknowns when it comes to defeating the armor package of the M1. Almost certainly a NERA set up for the turret, what type of steel is used (HHS?) is there a ceramic backing plate? as there appears to be on the turret side. I could see a Bm-32 having no problems, BM-22/26...hmmm I disagree with you here, very specific designs against a very specific target type, and too easy to cause critical failure of the round. Not saying it isn't possible to defeat the M1 armor package. Seems like armor and ammo were at the limits of what each could handle with regards to each other.

 

Zero doubt the Leo-2 could manage better. As far as perforated armor goes, I have vague memories of reading about it in the past as a German French approach.. but have seen no evidence of it further then that.

 

Didn't the Leo 1 side turret armor have at some stage a lattice structure designed for edge effects ?

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Leo 1A1A1 (IIRC) has a slotted mesh embedded in a rubber-like material on the turret. Once can speculate as to the defeat mechanism it's supposed to provide, but edge effects seems like a good enough start.

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Leo 1A1A1 (IIRC) has a slotted mesh embedded in a rubber-like material on the turret. Once can speculate as to the defeat mechanism it's supposed to provide, but edge effects seems like a good enough start.

Seems like a combination of NERA style defeat and edge effect.

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NERA is?

Thank you.

Non-Explosive Reactive Armor. Usually two High-Hardness Steel(HHS) plates with rubber or comparable material between them. In case of high-energy impact rubber accumulates energy and uses it to throw plates in the way of penetrator/HEAT jet.
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1. The add-on armor used on the Leopard 1A1A1 and the Jaguar 1 and 2 tank destroyers is not a wire mesh, I also wouldn't call it a lattice screen. While there are perforations in the side/cheek armor modules, I am not sure if these are related to the defeat mechanism of the armor. The patent describing this armor, or maybe just one patent from the company that manufactured this armor, is not mentioning perforations in the armor at any point. It is speaking of rubber-clad steel plates, which are made of an alloy that is hard and brittle, but not suited for welding.

Most of the frontal section of the tank is covered by the gun mantlet add-on armor, which does not have perforations or a rubber coating/cladding. I think it is possible, that the perforations (or maybe they are only indentations?) simply serve the purpose of allowing the properly connect the rubber to the steel plates.

 

2. At least the early NERA/NxRA arrays did not use high-hardness steel plates for the bulging parts, due to the limitations of the material. Even more recent armor arrays tested/used as reference in different research papers seem to utilize rather "soft" (by modern standards) steel plates for the bulging plates.

 

3. NERA is Non-Energetic Reactive Armor, which consists of steel plates and a material that does not undergo any sort of chemical reaction during the process of being penetrated. Commonly compressible materials like rubber, Dyneema and other polymeres are used, but it is also possible to use simply steel coils. In general all (or most, if the sandwich layer is already compressed) of the energy that moves the armor plates into the path of the projectile is taken from the projectile and simply redirected.

Non-Explosive Reactive Armor on the other hand is abbreviated as NxRA. It typically has a layout comparable to ERA, but the high-explosive is replaced by one or multiple material that exothermically react together, once activation energy is delivered (in form of the impact energy of the projectile) or a physical barrier separating the chemical compounds is penetrated. The reaction typically creates a gas (like O² for example), which due to the higher pressure will move the steel plates.

Edited by methos
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NERA is?

Thank you.

Non-Explosive Reactive Armor. Usually two High-Hardness Steel(HHS) plates with rubber or comparable material between them. In case of high-energy impact rubber accumulates energy and uses it to throw plates in the way of penetrator/HEAT jet.

 

Thank you.

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Posting here as it is the only live thread - Does anyone have data giving TE/ME for carbon fibre reinforced epoxy ?

Most of what I have relates to ballistic-domain impacts and/or carbon-fiber as a minor component in composite systems. These are relevant to hypervelocity impact:

 

http://ciar.org/ttk/mbt/papers/ijie02/armor.x.ijie.vol23.pp519-532.normal_and_oblique_hypervelocity_impact_on_carbon_fiber_peek_composites.taylor_tennyson.1999.pdf

 

http://ciar.org/ttk/mbt/papers/ijie02/armor.x.ijie.vol23.pp883-893.hypervelocity_impact_on_carbon_fibre_reinforced_plastic_aluminum_honeycomb_comparison_with_whipple_bumper_shields.taylor_herbert_vaughan_mcdonnell.1999.pdf

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Does NERA actually have a substantial effect on long rod projectiles? I always hear that Kontakt-1 has no effect whatsoever on KE penetrators, but it doesn't make sense to me that Kontakt-1, an ERA with two plates of two 2mm steel plates sandwiching 7mm of high explosives would perform worse than a NERA with, say, something like two 3mm steel plates sandwiching a 10mm interlayer of plastic or rubber or something. One is obviously more energetic than the other. The only explanation I can think of is that Kontakt-1 would indeed be more powerful than NERA... If it does not fail to detonate when hit by a long rod projectile. If Kontakt-1 is useless against long rod projectiles, then how much of an effect could NERA possibly have?

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Does NERA actually have a substantial effect on long rod projectiles? I always hear that Kontakt-1 has no effect whatsoever on KE penetrators, but it doesn't make sense to me that Kontakt-1, an ERA with two plates of two 2mm steel plates sandwiching 7mm of high explosives would perform worse than a NERA with, say, something like two 3mm steel plates sandwiching a 10mm interlayer of plastic or rubber or something. One is obviously more energetic than the other. The only explanation I can think of is that Kontakt-1 would indeed be more powerful than NERA... If it does not fail to detonate when hit by a long rod projectile. If Kontakt-1 is useless against long rod projectiles, then how much of an effect could NERA possibly have?

Well, depends of exact composition. Said 3mm steel with rubber between will do little to nothing. Something like T-72B with 21mm and 3mm HHS plates will mess rod pretty hard.
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Does NERA actually have a substantial effect on long rod projectiles? I always hear that Kontakt-1 has no effect whatsoever on KE penetrators, but it doesn't make sense to me that Kontakt-1, an ERA with two plates of two 2mm steel plates sandwiching 7mm of high explosives would perform worse than a NERA with, say, something like two 3mm steel plates sandwiching a 10mm interlayer of plastic or rubber or something. One is obviously more energetic than the other. The only explanation I can think of is that Kontakt-1 would indeed be more powerful than NERA... If it does not fail to detonate when hit by a long rod projectile. If Kontakt-1 is useless against long rod projectiles, then how much of an effect could NERA possibly have?

Well, depends of exact composition. Said 3mm steel with rubber between will do little to nothing. Something like T-72B with 21mm and 3mm HHS plates will mess rod pretty hard.

 

 

Could you explain how? Tankograd doesn't say much other than that the heavy front plate helps energize the interlayer, which might not be possible with other NERA sandwiches because the penetrator would just put a hole through it and come out the other side.

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Could you explain how? Tankograd doesn't say much other than that the heavy front plate helps energize the interlayer, which might not be possible with other NERA sandwiches because the penetrator would just put a hole through it and come out the other side.

Well, that's somewhat the case. Thick HHS plate disturb penetrator pretty well by itself when it stabilizes, plus it won't bend, thus most energy from rubber goes to thinner plate, bending it heavier thus throwing bigger portion into the way of penetrator and conducting bigger side effect.
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Does NERA actually have a substantial effect on long rod projectiles? I always hear that Kontakt-1 has no effect whatsoever on KE penetrators, but it doesn't make sense to me that Kontakt-1, an ERA with two plates of two 2mm steel plates sandwiching 7mm of high explosives would perform worse than a NERA with, say, something like two 3mm steel plates sandwiching a 10mm interlayer of plastic or rubber or something. One is obviously more energetic than the other. The only explanation I can think of is that Kontakt-1 would indeed be more powerful than NERA... If it does not fail to detonate when hit by a long rod projectile. If Kontakt-1 is useless against long rod projectiles, then how much of an effect could NERA possibly have?

 

NERA and NxRA can have a substantial effect on the penetration capacity of APFSDS ammunition, but only in special layouts. As previously mentioned, NERA can already work like effective spaced armour, when using thick plates and steel alloys of higher hardness. Early NERA with only thin steel plates proved to be rather ineffective against APFSDS ammunition. In some of the documents on the development of Burlington armour, the British FVRDE seemed to be happy, that it didn't offer worse protection per weight than RHA...

 

More modern types of NERA making use of more advanced interlayer material (rubber is rather bad compared to modern composites) and steel that offers both ductility and hardness can be very effective against APFSDS ammunition, but it still needs to be rather thick. In research papers NERA sandwiches against APFSDS ammunition make use of some 15-20 mm thick steel plates of higher hardness.

 

 

The Leopard 2A5's wedge armor consists of multiple NERA plates with rather thick (20-30 mm ?) steel plates, supposedly with very high hardness.

 

Well, depends of exact composition. Said 3mm steel with rubber between will do little to nothing. Something like T-72B with 21mm and 3mm HHS plates will mess rod pretty hard.

The T-72B's NERA does not provide more protection against KE than simple spaced armor, according to German sources. Also the 3 mm HHS plate has been described as aluminium by some sources, other calls it normal steel. I have never seen a source claiming it is HHS.

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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
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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.

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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.

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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.

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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).

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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.

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