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The armour sceme i came up with:

 

10mm RHA, 150mm cavity with NERA-light at 14° from horizontal, 30mm RHA, 205mm cavity with NERA-light at 10° from horizontal, 30mm RHA, 25mm HHA (5mm airgap for mounting), 25mmHHA (5mm airgap for mounting), 25mm HHA (5mm airgap for mounting), 30mmRHA

 

Against ATGM 360mm precurser and 960mm main charge

 

First RHA layer Pres = 360 -10 =350

First NERA light layer Pres = 350/2.5 - 1.5*74 = 29

Second RHA Pres = 29 -30 = -1 precurser defeated

Second NERA light Pres = 960/3.3 -1.5*103 = 137

Third RHA Pres = 137 - 30 = 107

First HHA Pres = 107 -50 = 57

Second HHA Pres 57 - 50 = 7

Third HHA Pres = 7 -50 = -43 Main charge stopped

Fourth RHA not even scratched

 

Against 500mm KE

 

First RHA layer Pres = 500 -10 = 490

First NERA light layer Pres = 490/1.07 - 1.5*74 = 347

Second RHA Pres = 347 - 30 = 317

Second NERA light Pres = 317/1.11 -1.5*103 = 162

Third RHA Pres = 162 - 30 = 132

First HHA Pres = 132 -50 = 82

Second HHA Pres 82 - 50 = 32

Third HHA Pres = 23 -50 = -27 KE penetrator stopped

Fourth RHA not even scratched

 

Im getting about 4.2 tons to cover 1m^2

 

Everything is inert so no problems with that. all special armour is in cavities and can be replaced easily. Armour array is only 445mm deep. Can easily be upgraded with additional armour.

 

 

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1 hour ago, Lord_James said:

Pressing can laminate different metals together,

All that is required in the end laminate is intimate contact.  The softer, tougher plate behind is to protect the hard front plate from bending stress.  The hard plate has high harness but low toughness.  The two plates do not need to be metallurgicaly joined although that is relatively easy if we are talking two steel plates.  It does require high pressures and time as a substitute for heat - heat would make it fast and easy but there go the properties of the hard plate.  Bonding processes provide very nearly the same performance but I am not sure if we have the requisite vacuum epoxy technologies?

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15 minutes ago, DIADES said:

All that is required in the end laminate is intimate contact.  The softer, tougher plate behind is to protect the hard front plate from bending stress.  The hard plate has high harness but low toughness.  The two plates do not need to be metallurgicaly joined although that is relatively easy if we are talking two steel plates.  It does require high pressures and time as a substitute for heat - heat would make it fast and easy but there go the properties of the hard plate.  Bonding processes provide very nearly the same performance but I am not sure if we have the requisite vacuum epoxy technologies?

 

My books on armor technology explicitly say the opposite.

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56 minutes ago, holoween said:

The armour sceme i came up with:

 

10mm RHA, 150mm cavity with NERA-light at 14° from horizontal, 30mm RHA, 205mm cavity with NERA-light at 10° from horizontal, 30mm RHA, 25mm HHA (5mm airgap for mounting), 25mmHHA (5mm airgap for mounting), 25mm HHA (5mm airgap for mounting), 30mmRHA

 

Against ATGM 360mm precurser and 960mm main charge

 

First RHA layer Pres = 360 -10 =350

First NERA light layer Pres = 350/2.5 - 1.5*74 = 29

Second RHA Pres = 29 -30 = -1 precurser defeated

Second NERA light Pres = 960/3.3 -1.5*103 = 137

Third RHA Pres = 137 - 30 = 107

First HHA Pres = 107 -50 = 57

Second HHA Pres 57 - 50 = 7

Third HHA Pres = 7 -50 = -43 Main charge stopped

Fourth RHA not even scratched

 

Against 500mm KE

 

First RHA layer Pres = 500 -10 = 490

First NERA light layer Pres = 490/1.07 - 1.5*74 = 347

Second RHA Pres = 347 - 30 = 317

Second NERA light Pres = 317/1.11 -1.5*103 = 162

Third RHA Pres = 162 - 30 = 132

First HHA Pres = 132 -50 = 82

Second HHA Pres 82 - 50 = 32

Third HHA Pres = 23 -50 = -27 KE penetrator stopped

Fourth RHA not even scratched

 

Im getting about 4.2 tons to cover 1m^2

 

Everything is inert so no problems with that. all special armour is in cavities and can be replaced easily. Armour array is only 445mm deep. Can easily be upgraded with additional armour.

 

 

 

~~The package we’re using is better.~~

 

Edit: RIP my math skills, I was wrong.

Edited by A. T. Mahan
Math error
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I think holoween and Toxn have basically the right idea.  If you have an array of reactive elements, the reduction is going to be of the form K1^N where K1 is your coefficient from the curve and N is the number of reactive elements.  And if I remember anything from those finance courses that I never actually took, it's that compound interest is the most powerful force in the universe, and you get a lot more mileage from ABX by making X bigger than you do from worrying about A or B.

 

At least if you aren't concerned overmuch about thickness.  Toxn's array of 10 light NERA at 64 degrees is going to be like, 850mm thick, which is doable for turret front protection, but maybe a bit much for the sides.

Maybe figuring out a workable frontal protection scheme is actually the easy part.

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16 minutes ago, Collimatrix said:

My books on armor technolog

Quick check at my end - I am guessing yous ref something like "Metallurgical Factors Affecting the Behavior of Steel Targets" 1972 ?  That is still referenced and absolutely supports your comment.  That work reports on roll bonding from the 1960s (deeply appropriate!).  More recently explosive bonding has been used, much, much better results.  Also isostatic hot press but explosive is better/easier.  I am still digging for my bonding ref - pretty sure it was in the context of dissimilar metals.

 

But, we can use explosive bonding....

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14 minutes ago, DIADES said:

Publication dates?  Steels definitely can be easily metallurgicaly joined.

 

 

It's from 2016.  Different steel hardnesses can definitely be joined by explosive welding or by roll bonding, and dissimilar metals can be joined with explosive welding.  Not all combinations of dissimilar metals work, but a lot do.

 

No, what I'm objecting to is the idea that putting a high hardness plate up against an RHA plate without welding them along the face where they contact will work.  That very explicitly does not work well.  The synergistic effect would be quite small.

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4 minutes ago, A. T. Mahan said:

 

I’ve gotten better protection at substantially lower areal density. 

 

its not that hard really.

if i just take my array and remove the first and last RHA plates and switch my first NERA layer to ERA ill save quite some weight. i could also space my HHA plates more for better effect against KE

But it would reduce the uparmouring potential and increase the armours bulk by quite a bit

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3 minutes ago, Collimatrix said:

I think holoween and Toxn have basically the right idea.  If you have an array of reactive elements, the reduction is going to be of the form K1^N where K1 is your coefficient from the curve and N is the number of reactive elements.  And if I remember anything from those finance courses that I never actually took, it's that compound interest is the most powerful force in the universe, and you get a lot more mileage from ABX by making X bigger than you do from worrying about A or B.

 

At least if you aren't concerned overmuch about thickness.  Toxn's array of 10 light NERA at 64 degrees is going to be like, 850mm thick, which is doable for turret front protection, but maybe a bit much for the sides.

Maybe figuring out a workable frontal protection scheme is actually the easy part.

 

 I think the side armor is fairly reasonable if you have the right idea, and design a large enough vehicle to support thick side armor

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If you want to optimize for weight a single NERA light at 10°from horizontal followed by a single NERA heavy at 10° from horizontal will easily stopp all threats and for 1m^2 it weighs around 3 tons. you will need a build depth of a meter to reach good coverage though.

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56 minutes ago, DIADES said:

Cimpoeru?

 

 

Hazell 2016 and Crouch 2017.

 

They note that laminated steel armor that's assembled by explosive welding actually works better than roll bonded because the bond between the two plates is more robust (though there are caveats WRT residual stress).

 

Unless N-L-M says otherwise explicitly, I don't think you can use laminated steel structures.  Hand-wave it as the Californians not having sufficient industrial capacity to mass-produce such materials or something.

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1 minute ago, Collimatrix said:

I don't think you can use laminated steel structures.  Hand-wave it as the Californians not having sufficient industrial capacity to mass-produce such materials or something.

Agreed.  I don't intend using it - I am watching the adults discuss solutions and will adopt something from the resulting menu.  Basic config will drive the answer as much as amour drives config.

 

Explosive forming/bonding in one operation is actually pretty low tech.  Tank of water, stuff to go bang, two plates (to be formed/bonded) massive mould (concrete backed)  Could make nice curved modules.  But, I ain't going there.

 

Crouch, Ian?

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1 minute ago, holoween said:

If you want to optimize for weight a single NERA light at 10°from horizontal followed by a single NERA heavy at 10° from horizontal will easily stopp all threats and for 1m^2 it weighs around 3 tons. you will need a build depth of a meter to reach good coverage though.

 

I'm... not following.

 

The 60mm/160mm tandem ATGM has 360mm penetration primary.  Light NERA at 10 degrees is about 3.5 K1 coefficient, so that drops to 102mm penetration.  K2 is 18*1.5/cos(10 degrees), or about 27.4mm, so there is 75mm residual pen after the first light NERA casette.

 

Also, I think you'd get murdered on the above-line-of-sight requirement because the missile would hit the top of the array and bypass the first reactive armor casette entirely.

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5 minutes ago, DIADES said:

Agreed.  I don't intend using it - I am watching the adults discuss solutions and will adopt something from the resulting menu.  Basic config will drive the answer as much as amour drives config.

 

Explosive forming/bonding in one operation is actually pretty low tech.  Tank of water, stuff to go bang, two plates (to be formed/bonded) massive mould (concrete backed)  Could make nice curved modules.  But, I ain't going there.

 

Crouch, Ian?

 

Indeed, Ian G. Crouch.

 

I remember looking into explosion welding and being surprised how simple it is.

 

 

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20 minutes ago, DIADES said:

Probably save some time and brain pain if we just go by the scenario detail provided.  Armour materials are detailed.

 

I just want to give the tank crews fire-protective clothing and body armor. It's nothing to do with the tank armor itself, but with keeping the crew from burning to death or getting killed when some Mormon shoots them in the chest while they're turned out.

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14 minutes ago, A. T. Mahan said:

 

I just want to give the tank crews fire-protective clothing and body armor. It's nothing to do with the tank armor itself, but with keeping the crew from burning to death or getting killed when some Mormon shoots them in the chest while they're turned out.

Fair enough but good luck getting tank crews to wear armour.  Too restrictive.

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My experience with AFV interiors is that they are too tight for ease of movement even if one was stark naked and fully greased up..........

 

Your body needs to conform to all the snags, lumps, protrusions and shit, your gear constantly gets caught.  WHEN a vehicle brews up, you need out.  Every gram and every millimeter of cloth/gear is a hindrance.

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