Armor topic

[HerrTom]

Unfortunately, I don't know how to model explosives very well in the software yet. I agree, it would be pretty interesting.

I redid it with 68 degree slopes, and increased the range to around 2 km (using -10% energy per km).  The shot failed to penetrate, though.  I may have an incorrect steel as the M829's tip, which I'm using S-7 tool steel.  I also got rid of the antiradiation liner, since I honestly don't really know what it's made of.  Not that it mattered here.  I also realise that the colouring in the last video may be a little confusing, so I changed it to just the body colours.

An interesting thing you don't really think about is that at these energies, metals start to behave like viscous liquids.  It's very cool.

 

[Vanir Ausf B]

APFSDS should ignore slope effects up to around 80 degrees from vertical.

[HerrTom]

Ah, I thought it didn't look quite right.  Probably because I set all body interactions to frictionless, which in retrospect is probably not the case in this high angle situation.  I'll run it again with that change and then stop spamming this thread with my dumb animations.

Anyway, the takeaway I'm getting from what I've seen is that these penetrators get really messed up when they go through things.  I don't think it's very likely you'll be KO'ing multiple T-90s with a single round.  Thin APC armour on the other hand is a different story.  The rods (and even the steel tip, to an extent) cut through thin armour like that as if it were paper, which I hope is no surprise to anyone! 

[John Kettler]

Haiduk,

If you're going to quote Russian to make a point, please also provide at least the gist in English.

HerrTom,

Welcome aboard!

Very much appreciate this dynamic simulation work by you. Presumably, this is with a perpendicular strike, on a perfectly level target, against vertical armor. I fervently hope you can address the effective thickness case BTR presented. In my fondest dreams, I'd love to see some representation of how a long rod penetrator really behaves when encountering substantial armor.

Update

My edit with all the research took so long you'd completed the angled case before I could submit my edit. Well done!

BTR,

Thanks much for the terrific M829A3 link. Your point about the armor array as seen by the incoming KE penetrator is apt. Given my understanding of the ERA under discussion works, I would expect the ERA to pitch the nose of the penetrator at least somewhat upward, further increasing the effective thickness. How does the 100 mm diameter of the M829A3 compare with that of the M829A2? If they are the same, then it seems to me that the issue of long rod failure in shear ought perhaps also to be considered in assessing terminal effectiveness of the M829A3. Or does the new nose somehow confer immunity to shear?

Present

For you projectile terminal ballistics grogs, here's a full-on engineering analysis of tungsten KE penetrators vs three different types of target arrays, one of which is somewhat akin to our case.

http://dtic.mil/dtic/tr/fulltext/u2/a281384.pdf

 PRETEST PREDICTIONS OF LONG-ROD INTERACTIONS WITH ARMOR

TECHNOLOGY TARGETS  

Charles E. Anderson, Jr. and David L. Littlefield

U.S. Army Research Office
P.O. Box 12211
Research Triangle Park, NC 27709-2211

 

April 1994 

 

This capability sheet from the famed Southwest Research Institute shows what I mean by the nonlinear behavior of long rod penetrators after striking the armor array.

http://www.swri.org/3pubs/brochure/d18/ArmMech/ArmorMechFlyer.pdf
 
But the pure gold is here. A doctoral dissertation in Engineering based on no fewer than four separate full-on engineering studies of precisely the matters we're seeking to grok. Moving plate and shaped charges vs long rod penetrators. The illustrations alone are the stuff of armor scientist/engineer/grog/buff dreams.
 

https://uu.diva-portal.org/smash/get/diva2:359770/FULLTEXT01.pdf

Interaction Between High-velocity Penetrators and Moving Armor Components,

Ewa Liden (missing diacritical from me), Uppsala University, 2010
 

Regards,

John Kettler
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

 

Edited February 15, 2016 by John Kettler

[HerrTom]

So I ran it with friction, and the result is pretty much the same.  It did a slightly better job penetrating, but the steel tip still just doesn't dig in.  Though, admittedly, the rod is pretty oblique, and at these ranges would likely be coming in at a larger angle than straight on, as I have it.

This is all for me, for now, since these take quite a while to do, and I have other (probably better) things to do with my time.  I hope at least some of the information was useful!

John Kettler, nice find on the papers there.  They're quite the interesting read.

[John Kettler]

HerrTom,

Fascinating work! I think it would be potentially worthwhile to run your sim sometime with polyethylene in one case and Textolite in the other as the radiation protection layers. Offhand, I'd expect polyethylene to create a lot of viscous drag on the penetrator, certainly more drag on the already decelerating penetrator than simply passing through an air gap. As for Textolite, I found some Items. Glass Textolite (abstract of 10-page 1966 Department of the Navy doc). The good news? The abstract is juicy. The bad news? Textolite is frighteningly variable in a bunch of ways. It would help hugely if a sample from a Russian armor array had been or were to be analyzed, so that proper modeling could be done. Textolite is apparently something invented by General Electric and began production in the 1930s. In any event, I believe you've done much to educate and inform us on a little known topic. Am glad you found the papers relevant.

Regards,

John Kettler

Edited February 15, 2016 by John Kettler

[BTR]

Particular questions of terminal ballistics pg. 560 (published by Bauman Moscow State Technical University on behalf of NII Stali, 2006). 

First entry is textolite in combined arrays with steel.  

Where coefficients to RHAe are:

• К_г^КС = Density coefficient vs HEAT
• К_м^КС = Mass coefficient vs HEAT
• К_г^БПС = Density coefficient vs APFSDS
• К_м^БПС = Mass coefficient vs APFSDS
• ρ = Density g/cm³

PS HerrTom, looks like your perpetrator density are a bit off. It is deforming way to quickly. Here is an example of 3BM11 munition from 122mm 3VBM4 round impacting 300mm of RHA at 1246m/s.

 

 

Edited February 15, 2016 by BTR

[panzersaurkrautwerfer]

Not trying to be all "this is impossibru!!!!!!" but speaking as a non-engineer, something is up.  The T-90 hull has been a pretty well known variable for a while, and it has reached enough export proliferation to be considered on the threat tank list (unlike say, the T-64 post cold war).  The M829A2 is still widely issued, let alone the M829A3.  The A4's main push is ERA defeat.  If the frontal slope of a T-90 without ERA could handily defeat a sabot, there'd be some major motions and shake-ups, war on terror distraction or no (or see the A4's development cycle basically).  The Army was also fairly honest, if not at times aggressive about asserting what could, or couldn't kill threat vehicles,* and historically has used the danger posed by enemy vehicles as a way to lobby for more funding.  This has not happened.

Which leads me to believe that there might be other forces at work, or at the least, modeling penetrator vs armor is tricky to say the least.  



*It took until post 1991 for .50 caliber to be considered as effective against BTRs and BMPs for exercises, because someone could point to the various well ventilated BMPs out in the desert and point to where the .50 cal penetrated.  While the MPAT and older HEAT rounds would out and out kill a T-62 and down without breaking a sweat, you couldn't get away with using it in the simulators.  

[HerrTom]

No, panzersauerkrautwerfer, you're completely right.  I'm honestly not that experienced with explicit dynamics simulations like above, my area of expertise is only rocket science!  My work involves fluid dynamics, combustion and heat transfer, a far cry from this.

There are a number of things here that are probably affecting the result:
1) I don't really know what steel the tip is made of, so I took an assumption it was a form of tool steel.  This may not be right.
2) The exact geometry is only an approximation from the picture.  The tip roundness may be wrong, as well as the ogive shape of the tip, which I imagine also greatly affect the results.
3) From the above, the deflection of that steel tip causes the uranium rod to fail as it passes through the first layer, causing it to essentially shatter on the next layer.
4) The size of the finite element mesh also is a big factor here.  It's relatively big and coarse for those animations since I'm impatient and don't want my computer's resources hogged for 300+ hours!

If I get a more realistic looking result though, I'll post it.

[panzersaurkrautwerfer]

Only rocket science.  That's pretty much just a step up from burger rotation tbh.

I don't really know much about the science behind it, or much science at all, the Sabot could have released a million tiny armor eating gnomes for all I knew.  However in training and planning, something north of a 80% kill rate was expected against a T-90 type target at 2500 meters against the frontal target (with rounds missingr, mobility/firepower kills, goes through things that don't kill the making up the .2 notakill).

This of course should be taken with the grain of salt that rarely does anything actually approach a .8 p/k in reality, but the armor array of most Russian tanks is exhaustively understood, and does not appear to present an undue challenge to modern sabot type rounds.    

[BTR]

Yesterday, in one of my QB's, I noticed that my veteran crews were "eyeballing" enemy vehicles at 500-800m without lazing them. I like this behavior, it makes real sense looking at how Russian sights are structured, but I've not seen this on any other tank other than T-72B3. Can somebody confirm this? 

[Vanir Ausf B]

My guess is the target had a damaged laser warning receiver.

[panzersaurkrautwerfer]

Yesterday, in one of my QB's, I noticed that my veteran crews were "eyeballing" enemy vehicles at 500-800m without lazing them. I like this behavior, it makes real sense looking at how Russian sights are structured, but I've not seen this on any other tank other than T-72B3. Can somebody confirm this? 

Think the broken laser warning receiver makes more sense.  I don't know the specs on Russian rounds, but if you're shooting M829 type rounds it doesn't deviate in any meaningful way from the crosshairs out to about 1200 meters (think it's 800 meters or so for HEAT, not sure about MPAT, let alone AMP), and there's even an FCS control that basically rigs the whole mess to operate without a laser input.

Back when CMBS came out there was some idle discussion about having tank crews not employ laser range finders at close range.  I think it'd be fair, but best linked to crew quality (a veteran crew being more likely to be confident enough in their gunnery to engage without the laser, while a green one would do what a lot of new tanks do, and burn out the laser from overuse before switching to manual).  

[BTR]

Think the broken laser warning receiver makes more sense.  I don't know the specs on Russian rounds, but if you're shooting M829 type rounds it doesn't deviate in any meaningful way from the crosshairs out to about 1200 meters (think it's 800 meters or so for HEAT, not sure about MPAT, let alone AMP), and there's even an FCS control that basically rigs the whole mess to operate without a laser input.

Back when CMBS came out there was some idle discussion about having tank crews not employ laser range finders at close range.  I think it'd be fair, but best linked to crew quality (a veteran crew being more likely to be confident enough in their gunnery to engage without the laser, while a green one would do what a lot of new tanks do, and burn out the laser from overuse before switching to manual).  

I can't say it could have been broken, the QB was in its opening 2-3 moves, but perhaps there is something I'm missing. For T-72 and derivatives there are several ways not to constantly ping the target with laser, and if you zero the sight in advance it should be good to up around 1000-ish m. Incidentally that is what they did in the fist tank biathlon - they didn't use the laser adjustments and targets were hit out to 1200m with practice rounds. Right now I'd almost take a 1974 vintage T-72 with optical rangefinder for close encounters than a more modern vehicle. 

I think linking more advanced and cunning gunnery to veterancy is the only way this can be done believably. 

Edited February 20, 2016 by BTR

[BTR]

More Snackbar videos, this time with T-90A vs a TOW (unsure which variant). Shtora in a non-jammer mode as far as I can see, and hatches open before impact. I suppose that is why the gunner gets shocked and flees the vehicle, otherwise no other damage visible.  

 

Edited February 26, 2016 by BTR

[Codename Duchess]

Lucky for that T-90 crew, assuming the other 2 are okay. Have there been many/any reported casualties amongst Russian ground forces? I haven't been tracking that closely.

[Ivanov]

Lucky for that T-90 crew, assuming the other 2 are okay. Have there been many/any reported casualties amongst Russian ground forces? I haven't been tracking that closely.

I was a Syrian crew. That explains why they had the hatches open and Shtora switched off 

[BTR]

Not Syrian crews. SAA does not operate T-90 variants at present. It is either a full Revolutionary Guards crew, or part IRGC, part Hezbollah crew. 

[panzersaurkrautwerfer]

My attempts to slowmo the video enough to figure out what flavor of TOW it was ultimately exceeded my patience.  In the middle east it could be anything from a Vietnam era TOW through a TOW-2A.  900 MM RHA penetration is about where the TOW-2/TOW-2A series tops out though, and even the not-ERA portions of the T-90's turret have estimates in the 870+ range.

So about to be expected.  The crew bailout is interesting though, I wonder if it's some former T-72 crew member going through the "oh god not again" drill.  Open hatches wouldn't have made as much of a difference in terms of crew shock from an external explosion though, although it makes a lot of sense if you're expecting some sort of in-turret effects.  If the various optics shattered, all the in-turret dust got thrown up, it'd be enough for fairly junior dudes to bail too though.

[BTR]

The tank hasn't yet appeared on Snackbar twitters as of yet, so I assume it got away. Not sure how the commander fared in this, but assuming gunner got out, commander had even better chances. 

[VladimirTarasov]

They need to be more careful with these tanks

[BTR]

Right...

https://en.wikipedia.org/wiki/Inshallah

 

[Haiduk]

My attempts to slowmo the video enough to figure out what flavor of TOW it was ultimately exceeded my patience.  In the middle east it could be anything from a Vietnam era TOW through a TOW-2A.  900 MM RHA penetration is about where the TOW-2/TOW-2A series tops out though, and even the not-ERA portions of the T-90's turret have estimates in the 870+ range.

Some sources say about 800 mm and 830 mm for T-90AM (additional screens). I went through other video of this armed group with TOW launches, but only on one I spotted some similar to yellow ribbon on missile container - the sign of BGM-71E. On other videos TOW launcher filmed counter to the sun and impossible to know what missile was shot BGM-71A or E. Also possibly it is true, that latest Kontakt-5 ERA can reduce on 10-20 % effectiveness of tandem ammunitions.

Edited February 27, 2016 by Haiduk

[panzersaurkrautwerfer]

Some sources say about 800 mm and 830 mm for T-90AM (additional screens). I went through other video of this armed group with TOW launches, but only on one I spotted some similar to yellow ribbon on missile container - the sign of BGM-71E. On other videos TOW launcher filmed counter to the sun and impossible to know what missile was shot BGM-71A or E. Also possibly it is true, that latest Kontakt-5 ERA can reduce on 10-20 % effectiveness of tandem ammunitions.

Yellow bands on a munition just means the presence of some sort of explosive filler. I'm not a munitions guy by training so again I might be off base, but that's the rule of thumb I've seen and if you look at other US produced missiles (and I think it's a NATO thing too) there's a lot of yellow bands on them, and the same for artillery rounds.  

The only markings I know of for sure that attest to different variants of weapon will be on the munition's dataplate.  

[DougPhresh]

Does this seem about right to everyone?


What kind of damage are we looking at?