How credible are SY simulations, Dejmian XYZ Simulations and other youtube channels?

[Malignity]

These channels, if you dont already know them, explore different combat situations between tanks by simulating various projectiles. I noticed that many simulations seem plausible, but in some cases modifiers of the simulation like armour or projectile hardness seem a bit off. What are your thoughts?

[ThatZenoGuy]

I think the simulation has issues with battleship-scale weaponry (Iowa's outer hull decapping an 18.1 inch shell, which shouldn't be possible), but the tank-grade weaponry seems about right, although it appears to make sloped armor a bit more resistant than historical.

[Thoddy]

in some of the simulations the Pzgr behave like a eroding rod.

I suspect its difficult to simulate decremental hardening of shell in a apropriate manner (and more difficult sheat hardening for heavy naval shells)

additionally projectile and armor were not as homogeneous as the simulations indicate(microstructural composition/fine grain <->coarse grain).

[ThatZenoGuy]

in some of the simulations the Pzgr behave like a eroding rod.

I suspect its difficult to simulate decremental hardening of shell in a apropriate manner.

additionally projectile and armor were not as homogeneous as the simulations indicate(microstructural composition/fine grain <->coarse grain).

Unless I am mistaken it is not possible to simulate various hardness of a material, a projectile body has to be a single hardness throughout.
Hence why the only parts of the shell which act differently is the cap, as it is indeed a separate simulated part.

[Peasant]

Unless I am mistaken it is not possible to simulate various hardness of a material, a projectile body has to be a single hardness throughout.
Hence why the only parts of the shell which act differently is the cap, as it is indeed a separate simulated part.

I believe you can: https://www.quora.com/Can-we-define-two ... d-in-ansys

[ThatZenoGuy]

Unless I am mistaken it is not possible to simulate various hardness of a material, a projectile body has to be a single hardness throughout.
Hence why the only parts of the shell which act differently is the cap, as it is indeed a separate simulated part.

I believe you can: https://www.quora.com/Can-we-define-two ... d-in-ansys

https://www.youtube.com/watch?v=WVvA6TYXMLI

As an example of one of his videos he doesn't show any form of variable hardness/properties of the 88mm shell.
Additionally I admit I have no experience using ANSYS but there's a difference between 'two materials per solid' and a progressive material change through a solid.

He might use hardening simulation, but I don't think there's any proof of it. I will ask him!

[Thoddy]

typical post 1943 hardness curves

[Mobius]

In their videos the target plate is unmoving and static. I've seen highspeed videos of an impact and the plate had visible shock waves emanating from the impact point.

[Thoddy]

there is a fairly new Sim
https://www.youtube.com/watch?v=bffm_dhyvao

"ISU-122 vs Tiger II Armor Penetration Simulation"

Simulation of ISU-122 tank projectile hitting the turret front armor of Tiger II tank (185 mm at ca 10° obliquity)
D-25 gun ; 122mm BR-471B (25 kg AP projectile) at 770 m/s.

I cant believe that a slug type projectile can defeat approximately 1,5 cal RHA with the projectile basically whole.
slugs compete very well with standard tipped projectile up to about 0,8 cal plates due to their plugging type penetration.

But they were bad piercers -as required for large T/D- due to their head shape and in addition, tip/head hardness was significantly lower then for instance german (post 1943) and american armor piercing projectiles.
I have seen a hardnes profile of this projectile somewhere but not at hand.

Against about 1 cal plate this shell should invariably shatter. Or are there known real results wich confirm the result of this "simulation."

may be a penetration with shattered shell appears possible, but at significantly increased impact velocity.

i have launched a comment
"​ @Dejmian XYZ Simulations with regard to performance of german shell there was a marked difference in performance, between pre 1942/43 shells and post 1942/43 shells. Despite having the same designation Pzgr 39 etc pp., the new post 42/43 shells would outperform the obsoelete shells by a large margin.

For instance the performance of the old 8,8 cm Pzgr flattens out at about 850 m/s versus 100 mm armorr plate at 30 degrees obliquity due to increasing projectile deformation followed by breakup during penetration at increasing impact speeds.

But the newer shell of same weight but improved hardening profile achieved about 150 mm at 850 m/s at 30 °. This new shell in general remain whole up to impact speeds greater then 1100 m/s against armor plate of >240 mm thickness. Source: Bericht 166 der Lilienthalgesellschaft -Vorgänge beim Beschuss von Panzerplatten; Einige Praktische Erfahrungen im Panzerplattenbeschuss bei der Entwicklung von Panzergranten über 3,7 cm beim Heer; lecture by J.Sitz, Berlin 20./21 Mai 1943 Berlin Geheime Kommandosache.

As been said, the hardness profile of shell was improved ... to about 61 RC at the tip. This hardness strongly reduces deformation during the penetration process by compression and -at the same time- enables a high performance at high obliquity (say 60° degrees obliquity). In this regard I recommend the read of DEFE 15-452 A Fundamental Investigation into the Optimum Hardness for a Capped Armour Piercing Shot available at the National Archives London.

next:
when thickness of plate exceeds ca one caliber thickness then the piercing performance of projectiles with finer tips significantly exceeds the performance of shell with shorter or flat heads. I would recommend "Effects of Impact and Explosion", Summary technical report of the national defense research commitee Washington DC 1946.

in addition flat head shell usually shatter against plate of thickeness greater then 1 cal as the compressive forces during pentration exceed the projectile strenght porovided by material properties.
Maybe a penetration with shatterd shell appears possible, but at a increased velocity."

[Peasant]

The issue I see here is not that the armour is too weak, but rather the projectile is too strong. It suffers minimal damage as it penetrates the target, which makes it almost as efficient as a high quality sharp tipped AP projectile. It leaves about a caliber sized hole in the armour, unlike what we see in real life tests of soviet guns where the shell breaks up and spreads like a soft lead bullet, leaving a crater about x1.5 -2 calibers wide.

A similar situation of soviet blunt tipped shell attacking a greatly overmatching plate was a 57mm ZiS-2 gun fired at Tiger I superstructure side during tests in 1943. The obtained 50% Army limit was about 723m/s and the Navy limit about 750m/s. This performance is in line with other data I have, and DeMarre equation would suggest that a 122mm 25kg shell would need about 814m/s striking velocity to at least produce a cracked bulge on the back of a 185mm plate set at 10°angle.

I wish he would've made another simulation with this target + gun combination but this time at a much lower velocity to compare the results with what the soviets got here:

"122mm AP shell. Striking velocity: 602,3m/s. Dent, 230x200mm large, 90mm deep. A 10mm high bulge on the rear with small cracks."

Another similar case, 122mm gun vs Ferdinand. 1400m. For BR-471 shell with m.v. = 781m/s this is 611m/s.

Dent 100mm deep. A negligible bulge at the rear. Thickness at the impact point: 200mm.

[ThatZenoGuy]

So in a nutshell some of these simulations don't have proper shell deformation?

[critical mass]

Sort of. But it is very difficult, too, because the shells have both a complex hardness contour and a complex gradient, plus a tensile contour (which is inversely correlated with hardness, but may deviate from it where the steel was embrittled).
Its good to see Dejmian employing shear bands, though.

[Malignity]

Talking of which, critical mass, did you study projectile physics?

[Peasant]

A new challenger appears!

https://www.youtube.com/channel/UCTDZyH ... C5-eh2EOjA

[Peasant]

The simulation on this author seem more grounded in reality, as in: no absurd scenarios like "800mm shell vs M1 Abrams".

https://youtube.com/watch?v=O6pBQG57d4w