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12 minutes ago, Iron Drapes said:

That's just spaced steel plates, isn't it?

In case of Soviet T-72Bs - no. There is not much of "spacing" and "just steel plates" inside of the armor package IDK if Iranian T-72s retain Soviet T-72s UFP layout.

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On 6/17/2017 at 9:54 PM, LoooSeR said:

In case of Soviet T-72Bs - no. There is not much of "spacing" and "just steel plates" inside of the armor package IDK if Iranian T-72s retain Soviet T-72s UFP layout.

 

Well, it depends on the modification, but the two b&w photos given by Militarysta definitely show nothing but steel plates.

 

 

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On 6/18/2017 at 0:20 AM, Militarysta said:

 

No, there are sevral NERA layers:

 

ognwCZG.jpg

 

 

In case Ob.184 before 1984 (and propably some late T-72A) we have simple steel plates:

 

pBUysxW.jpg

 

NihpEZb.jpg

 

It's weird that they could incorporate NERA into the turret but not the hull until much later in the production run. Any idea why?

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12 hours ago, Iron Drapes said:

 

It's weird that they could incorporate NERA into the turret but not the hull until much later in the production run. Any idea why?

 

Maybe the turrets and hulls weren't assembled in the same place?  The earliest T-72 versions had composite hull armor and all steel turrets, after all.

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The effectiveness of additional protection of military vehicles

 

Quote

   Below you can find the translation of this article: "Эффективность дополнительной защиты военной техники" ("The effectiveness of additional protection of military vehicles").

   Date of publication: 15.02.2017 (Authors: Evgeny Chistyakov, Dmitry Kupryunin, Mikhail Alexeev, Alexey Kimayev)
   Date of translation: 01.07.2017-02.07.2017


   Note: I want to thank for the help in translating @Urich_jr, and also @warsmonitoring for the idea of this translation. Thank you once more, guys!

 

   The effectiveness of additional protection of military vehicles

   Armed conflicts in recent years convincingly show that military hardware used in them constantly needs to strengthen protection, while other important parameters - firepower and mobility - are often superfluous. For example, a tank in the city does not need a gluttonous engine with a capacity of 1500-1800 h.p., and the armor-piercing capabilities of the gun required in very rare cases. The problem with the deficit of protection increases many times, when modern weapons and obsolete armored vehicles with a low level of protection are involved in the conflict. These scenarios are mainly happens now.
.........(read futher in the link, article is pretty long)

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16598_900.jpg

 

 

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Polish simple NERA armour= better cut-viev:

 

4YB7wQa.jpg

 

the same descibe here:

 

 

bs2gMXR.jpg

 

yd73zzX.jpg

 



W ramach sfinansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego pro-jektu rozwojowego nr 0019/T00/2008/06 zrealizowano w WITPiS program badań ekspe-rymentalnych z użyciem granatów PG-7M, o przebijalności stali RHA 300330 mm.

Przeprowadzono badania modelowych rozwiązań ekranów prętowych (rys. 1) i kaset typu NERA. Uzyskano rezultaty, dla których nie następuje przebicie pancerza

(...)

Kasety typu NERA mogą być obecnie stosowane dla cięższych pojazdów lub tylko fragmentami dla lżejszych (np. tylko do ochrony przestrzeni załogowej). Ze względu na ich budowę gęstość powierzchniowa tych rozwiązań wynosiła w trakcie badań od 220 do 390 kg/m2. Skuteczność kaset NERA jest znacznie wyższa od skutecz-ności ochronnej ekranów prętowych.

Porównując gęstości powierzchniowe opracowanych konstrukcji, uzyskano roz-wiązania o dużej efektywności masowej w stosunku do stali RHA. Przebijalność tej sta-li dla granatu PG-7M wynosi 300÷330 mm tj. 2340÷2570 kg/m2. Dla kaset typu NERA, licząc gęstość powierzchniową osłony razem z pancerzem kompozytowym i spall-linerem, można uzyskać ochronę o efektywności masowej ok. 4÷4,5. Zastosowane wy-kładziny wewnętrzne (spall-linery) skutecznie redukują kąt rozlotu odłamków, zmniej-szając tym samym poziom zagrożenia zranieniem dla większej liczby osób znajdują-cych się wewnątrz pojazdu.

TRANSLATE:
As part financed by the Ministry of Science and Higher Education pro-development project No. 0019 / T00 / 2008/06 was carried out in WITPiS research program experimental with grenade PG-7M whit steel penetration - 300-330mm RHA.

Conducted studies of model solutions screens pannels (Fig. 1) and the armour type NERA. The results obtained, for which there is no armor penetration

(...)

NERA cassette type can now be used for heavier vehicles or just for lighter fragments (eg. Only to protect the crew). Due to the construction of the density of the solution during the tests was between 220 and 390 kg / m2. The effectiveness of cassettes NERA is much higher than the effective-ness of the protective screens rod.

Comparing the density of developed surface structures obtained spread-linked with high efficiency mass relative to the RHA steel. Penetration of fixed-li for the grenade PG-7M is 300 ÷ 330 mm, ie. 2340 ÷ 2570 kg / m2. For cartridge type NERA, counting the density of the surface cover with composite armor and Spallliner, you can get the protection of the effectiveness of mass approx. 4 ÷ 4.5. O-used interior of the veil (Spall-liners) effectively reduce the angle rozlotu debris, reduce-stirring the same level of risk of injury to more people-smokers are inside the vehicle.

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15 hours ago, Toimisto said:

How would NERA do against full bore WW2 style AP ammunition? 

 

I am curious too.  Perhaps it's even happened.  There are enough old T-55s and old APCBC ammo for them out there.

 

11 hours ago, Mighty_Zuk said:

Quite well.

 

Could you elaborate on why?

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If you can significantly turn the projectile, and have a decent thickness of steel behind the NERA, it could work well. Get the hardened pointy bit away from the armour, and to projectile ought to break up when encountering significant resistance - kind of like sloped armour, only sloping the projectile instead. HVAP should also come apart against NERA for similar reasons

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Hi everyone,

 

This is my first post, but I've been lurking for quite a while. I was just wondering what the best materials are for making NERA out of, disregarding the costs? It seems to me that for the middle, reactive layer, you need to consider both how quickly it expands when struck, and also how much it expands (i.e. maximise the expanded volume:unexpanded volume ratio). I have no idea what the best material for this is, I assume the fact that's its usually rubber is simply to keep the costs down.

 

Because the purpose of NERA is to both force more of the expanding metal plates into the path of the KEP/HEAT jet, and to snap it in half, it stands to reason the best material for said plates would be something hard and dense; staballoy for example. It increases the weight, but due to the way NERA increases the protection for a given thickness of metal, and because the armor is mostly air anyway, surely it would be more efficient overall to use fewer layers of staballoy than more layers of steel NERA. Again, presumably the main everyone uses steel is simply to keep the costs down. Or am I just completely wrong?

 

Also, another question; there was another post showing how some NERA systems have kevlar embedded in them, between the rubber and steel layers, with claims of up to 60% increased protection compared to regular NERA. How exactly does kevlar increase the efficiency of NERA so dramatically?

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20 minutes ago, Shakie said:

Hi everyone,

 

This is my first post, but I've been lurking for quite a while. I was just wondering what the best materials are for making NERA out of, disregarding the costs? It seems to me that for the middle, reactive layer, you need to consider both how quickly it expands when struck, and also how much it expands (i.e. maximise the expanded volume:unexpanded volume ratio). I have no idea what the best material for this is, I assume the fact that's its usually rubber is simply to keep the costs down.

 

Because the purpose of NERA is to both force more of the expanding metal plates into the path of the KEP/HEAT jet, and to snap it in half, it stands to reason the best material for said plates would be something hard and dense; staballoy for example. It increases the weight, but due to the way NERA increases the protection for a given thickness of metal, and because the armor is mostly air anyway, surely it would be more efficient overall to use fewer layers of staballoy than more layers of steel NERA. Again, presumably the main everyone uses steel is simply to keep the costs down. Or am I just completely wrong?

 

Also, another question; there was another post showing how some NERA systems have kevlar embedded in them, between the rubber and steel layers, with claims of up to 60% increased protection compared to regular NERA. How exactly does kevlar increase the efficiency of NERA so dramatically?

 

Welcome to SH Shakie!

1)  I think @Bronezhilet had some papers on testing different materials in NERA arrays.  It looked like most of the materials were organic polymers, so rubber is probably not far off the mark ever if it isn't 100% ideal.  To be honest, I'm not sure exactly what's going on when the interlayers in NERA vaporize.  I'm not sure if it's just dissociating under the energy, or whether it's actually undergoing some sort of exothermic reaction like the fluorocarbon/metal mixtures in reactive shaped charge liners are.  I know that there have been experiments with doping the rubber layers in NERA with a bit of high explosive to give it some more kick.  In the experiment I saw, it didn't work particularly well.

 

2)  I believe that the heavy ERA designed specifically to counter KEPs is designed to snap the projectile.  Other reactive armors don't necessarily work the same way.  I've seen papers on ERA with low-density ceramic and polymer flyer plates, and it apparently works as well as steel on a weight basis.  Look up "The Defeat of Shaped Charge Jets by Explosively Driven Ceramic and Glass Plates" by Paul Hazell if you have access to journals and you're curious.  That said, there may be some use of heavier materials in reactive armor arrays.  @SH_MM is of the opinion that the depleted uranium in the Abrams' armor is incorporated into some sort of NERA, although I personally suspect otherwise.

3)  I was actually under the impression that the kevlar was providing energy for the movement of the metal plates, but I would have to double-check because I am not sure.  Aramids have very strong chemical bonds, and if those bonds were to come apart under the energy provided by an incoming penetrator, they should provide lots of energy for the plates.

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1 hour ago, Collimatrix said:

 

Welcome to SH Shakie!

1)  I think @Bronezhilet had some papers on testing different materials in NERA arrays.  It looked like most of the materials were organic polymers, so rubber is probably not far off the mark ever if it isn't 100% ideal.  To be honest, I'm not sure exactly what's going on when the interlayers in NERA vaporize.  I'm not sure if it's just dissociating under the energy, or whether it's actually undergoing some sort of exothermic reaction like the fluorocarbon/metal mixtures in reactive shaped charge liners are.  I know that there have been experiments with doping the rubber layers in NERA with a bit of high explosive to give it some more kick.  In the experiment I saw, it didn't work particularly well.

 

2)  I believe that the heavy ERA designed specifically to counter KEPs is designed to snap the projectile.  Other reactive armors don't necessarily work the same way.  I've seen papers on ERA with low-density ceramic and polymer flyer plates, and it apparently works as well as steel on a weight basis.  Look up "The Defeat of Shaped Charge Jets by Explosively Driven Ceramic and Glass Plates" by Paul Hazell if you have access to journals and you're curious.  That said, there may be some use of heavier materials in reactive armor arrays.  @SH_MM is of the opinion that the depleted uranium in the Abrams' armor is incorporated into some sort of NERA, although I personally suspect otherwise.

3)  I was actually under the impression that the kevlar was providing energy for the movement of the metal plates, but I would have to double-check because I am not sure.  Aramids have very strong chemical bonds, and if those bonds were to come apart under the energy provided by an incoming penetrator, they should provide lots of energy for the plates.

 

I see. I was under the impression that NERA worked basically the same way as ERA; just with less energy and multi-hit capability. I thought that was why there had to be air gaps between NERA sandwiches, so that the metal plates have something to expand into, rather than getting squashed against each other.

 

Also, I'm not sure if there's a separate thread for this, but here's my first (not to scale) attempt at armour design, I would appreciate it if someone would critique it. First, you have ceramic tiles encased in staballoy (the green/black layer) to break up the incoming projectile. Next there's the NERA (dark grey/brown layers), with rubber sandwiched between HHS plates and kevlar layers. Note that some of them are parallel to the first layer, while others are perpendicular; this is to put any incoming projectiles under as much stress/strain as possible. Then at the very back there's an air gap followed by a slab of Ti-6Al-4V to catch any remaining fragments. Finally, this whole arrangement, which is 400mm thick total, would be arranged in multiple layers to defeat multi-segment KEPs. For example, 3 identical such armour arrays could be arranged back-to-back, for 1200mm thick armour in total, and can defeat 3-segment KEPs. This would also keep production costs down since each layer is identical. Something similar could be used for the turret as well, though you'd have to arrange it carefully to manage the sheer bulkiness. I also haven't worked out how heavy it is.

 

3FfRjyD.png

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On 10/21/2017 at 10:16 AM, Shakie said:

 

I see. I was under the impression that NERA worked basically the same way as ERA; just with less energy and multi-hit capability. I thought that was why there had to be air gaps between NERA sandwiches, so that the metal plates have something to expand into, rather than getting squashed against each other.

 

My understanding is also that NERA basically works like a LOW ENERGY AND SAD version of ERA, only the energy is provided from the vaporization of the rubber interlayers caused by the incoming projectile rather than the detonation of an explosive.  Like I said, I'm fuzzy on whether the vaporization of the interlayer is exothermic or not.

That said, most ERA does not appear to work by damaging the incoming threat.  My understanding is that only heavy K5 style ERA works that way.  Most ERA works by feeding steel into the path of the threat.  A shaped charge jet erodes, and gets shorter as it penetrates a target, so by feeding metal obliquely into a jet the ERA essentially "uses up" the jet.

 

There's (a lot) more to it than that, but I think that's an accurate Cliff Notes version.

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Since this thread is more or less our general armor thread:

 

http://www.opex360.com/2017/12/17/pme-francaise-a-mis-point-blindage-plus-resistant-et-deux-plus-leger/

 

B4C ceramic claimed to have 20% more hardness than the typical B4C while being twice as light.

 

To achieve that they start with a nano powder of B4C and to keep the grain at a nano scale they use a flash sintering process (Pulsed current in a high pressure environment) claimed to be 20 times faster than usual process (so the grain don't have time to grow I guess).

 

No idea about the maximum size and the shape of the finished product.

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4 hours ago, Alzoc said:

Since this thread is more or less our general armor thread:

 

http://www.opex360.com/2017/12/17/pme-francaise-a-mis-point-blindage-plus-resistant-et-deux-plus-leger/

 

B4C ceramic claimed to have 20% more hardness than the typical B4C while being twice as light.

 

To achieve that they start with a nano powder of B4C and to keep the grain at a nano scale they use a flash sintering process (Pulsed current in a high pressure environment) claimed to be 20 times faster than usual process (so the grain don't have time to grow I guess).

 

No idea about the maximum size and the shape of the finished product.

 

I didn't think anyone actually used B4C in tank armour due to its cost? I thought they only used it to absorb neutrons in the event of a nuclear detonation.

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12 minutes ago, Shakie said:

 

I didn't think anyone actually used B4C in tank armour due to its cost? I thought they only used it to absorb neutrons in the event of a nuclear detonation.

I don't have any example on top of my head, but I think that it is used in both body armor and armored vehicles.

It's true that Boron is great neutron absorber too and that B4C is one of the material we think we'll use in gen IV fast reactors.

But still it's amongst the hardest material known to man so it's use for armor plating is obvious.

The only problem is that it is quite brittle so it has to be encased in small compartment.

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According to the CeramTec, one of the largest manufacturers of industrial and ballistic ceramics, boron carbide is not used in combat vehicles, only in body armor. However silicium carbide is supposedly used in some AFVs including the Puma IFV.

 

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