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155mmHE and MBT


F.T
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If the glacis of a modern tank is hit by a 155mm high-explosive shell, what is the overpressure inside the tank and will it kill the driver?

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Hard to say, to be honest. I believe that for most tanks it will at least be a mission kill, with a giid chance to put the tank completely out of action.

Tanks are designed to protect against large caliber artillery fire in 8...15m, sometimes 25m distance. Direct hits are a decidedly higher load on man and machine. Also, 125mm HE seems to be a common choice in the anti-tank role in Ukraine, which suggests to me that even heavier calibers probably do even more damage.

 

But if the overpressure inside the vehicle exceeds a certain threshold, who knows. I think that other destruction mechanisms are at play, like ripping open fuel tanks by cracking welds or the armor plate itself, and then igniting the fuel through the flame of the HE explosion (and hot metal fragments).

 

In short, I think the assumption that a direct hit of a 155mm artillery HE shell will effectively destroy an MBT is a pretty safe bet. How exactly it will be destroyed is a question about which I have no reliable information.

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2 hours ago, Ssnake said:

Hard to say, to be honest. I believe that for most tanks it will at least be a mission kill, with a giid chance to put the tank completely out of action.

Tanks are designed to protect against large caliber artillery fire in 8...15m, sometimes 25m distance. Direct hits are a decidedly higher load on man and machine. Also, 125mm HE seems to be a common choice in the anti-tank role in Ukraine, which suggests to me that even heavier calibers probably do even more damage.

 

But if the overpressure inside the vehicle exceeds a certain threshold, who knows. I think that other destruction mechanisms are at play, like ripping open fuel tanks by cracking welds or the armor plate itself, and then igniting the fuel through the flame of the HE explosion (and hot metal fragments).

 

In short, I think the assumption that a direct hit of a 155mm artillery HE shell will effectively destroy an MBT is a pretty safe bet. How exactly it will be destroyed is a question about which I have no reliable information.

Wouldn't anti-tank missiles be better equipped with high-explosive warheads? For example, a charge of more than 8kg.

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Evidently, that's not the case. The biggest difference seems to be that missiles tend to come in lightweight bodies and try to deliver primarily a HEAT jet, with spherical overpressure around the detonation point as an unavoidable side effect.

HE artillery shells come with a massive body, e.g. 8kg HE filler mass and 32kg steel for the surrounding shell. At at least doubled or even quadrupled mass, the impulse of the impacting round is equally doubled or quadrupled. I'd also think that the artillery shell deforms less than an ATGM body, so the stress on the armor plate of the impact location must be higher, too.

Combined, this probably means more cracks in plate and weld joints with the obvious consequences for the components underneath/behind the plate.

 

It's just a theory. I have no extensive experimental damage or first-hand experience with battle damage analysis.

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13 hours ago, Ssnake said:

Evidently, that's not the case. The biggest difference seems to be that missiles tend to come in lightweight bodies and try to deliver primarily a HEAT jet, with spherical overpressure around the detonation point as an unavoidable side effect.

HE artillery shells come with a massive body, e.g. 8kg HE filler mass and 32kg steel for the surrounding shell. At at least doubled or even quadrupled mass, the impulse of the impacting round is equally doubled or quadrupled. I'd also think that the artillery shell deforms less than an ATGM body, so the stress on the armor plate of the impact location must be higher, too.

Combined, this probably means more cracks in plate and weld joints with the obvious consequences for the components underneath/behind the plate.

 

It's just a theory. I have no extensive experimental damage or first-hand experience with battle damage analysis.

High explosive shells need to generate enough fragmentation to kill infantry far enough away. Missiles, on the other hand, can kill tank crews with shockwaves without the need for thick shells. So the missile can still stay light.

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14 hours ago, F.T said:

Wouldn't anti-tank missiles be better equipped with high-explosive warheads? For example, a charge of more than 8kg.

 

 

that would necessarily change the missile performance- its flight characteristics such as speed and/or range and maneuverability. moreover, that may also affect the system which is firing it- in the case of helicopters or jets, adding more weight, which would affect range and flight characteristics, in the case of gun fired missiles like you see in russian designed tanks- cannot exceed the bore diameter nor the carrying capacity of the magazine, nor of that of the autoloader because the two piece ammunition plus propellant have dimensions or shape that the carousel cannot adapt, or in the case of man-portable missiles and rockets- limit their carrying capacity or the ability to use concealment if the launcher becomes large enough to be a lot less inconspicuous. you don't just simply just add a larger warhead like that without having to go back and redesign the weapon system- that is to say, just increasing the warhead size isn't necessarily better it everything else has to be re-engineered, it probably fails a cost-benefit analysis, or else you would be seeing larger missiles. all of a sudden you find that you have a whole new slate of problems by doing that

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10 hours ago, Captain_Colossus said:

 

 

that would necessarily change the missile performance- its flight characteristics such as speed and/or range and maneuverability. moreover, that may also affect the system which is firing it- in the case of helicopters or jets, adding more weight, which would affect range and flight characteristics, in the case of gun fired missiles like you see in russian designed tanks- cannot exceed the bore diameter nor the carrying capacity of the magazine, nor of that of the autoloader because the two piece ammunition plus propellant have dimensions or shape that the carousel cannot adapt, or in the case of man-portable missiles and rockets- limit their carrying capacity or the ability to use concealment if the launcher becomes large enough to be a lot less inconspicuous. you don't just simply just add a larger warhead like that without having to go back and redesign the weapon system- that is to say, just increasing the warhead size isn't necessarily better it everything else has to be re-engineered, it probably fails a cost-benefit analysis, or else you would be seeing larger missiles. all of a sudden you find that you have a whole new slate of problems by doing that

As far as I can remember, the TOW has a 3kg charge, maybe 8kg is an acceptable value.

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10 hours ago, F.T said:

High explosive shells need to generate enough fragmentation to kill infantry far enough away. Missiles, on the other hand, can kill tank crews with shockwaves without the need for thick shells. So the missile can still stay light.

How do you get this idea? Did you even read Ssnakes comment?

How does the shockwave reach the crew inside?

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2 hours ago, F.T said:

As far as I can remember, the TOW has a 3kg charge, maybe 8kg is an acceptable value.

 

that is called a hellfire missile then. why arbitrarily choose a requirement for 8- why not go bigger and duplicate a maverick missile? the tow fills a gap for a lighter shorter range missile.  what would increasing the size and weight do that it isn't doing already which would merit the cost in weight that a person has to carry (for a larger warhead would mean a larger missile, which would change the requirements to adapt it for a new heavier launcher). where is the tow missile inadequate that a larger warhead is needed and where you essentially duplicate something which already exists? you're picking this larger figure, but why? what is the deficiency?

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12 hours ago, Grenny said:

How do you get this idea? Did you even read Ssnakes comment?

How does the shockwave reach the crew inside?

The explosion can cause the armor plate to move and deform, causing the air pressure behind the armor to rise, and even inducing a secondary shock wave if the energy is high enough. So even if the armor isn't perforated, the air overpressure behind the armor can be deadly. I'm just not sure if the 155mm He can produce dangerous overpressure behind the main armor of a modern tank.

The main armor of the tank is so thick, but the tank also has weak armor on top of the hull. Although I'm assuming it hit the main armor, the shockwave will diffract and also have an effect on the top of the hull.

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9 minutes ago, F.T said:

The explosion can cause the armor plate to move and deform, causing the air pressure behind the armor to rise, and even inducing a secondary shock wave if the energy is high enough. So even if the armor isn't perforated, the air overpressure behind the armor can be deadly. I'm just not sure if the 155mm He can produce dangerous overpressure behind the main armor of a modern tank.

The main armor of the tank is so thick, but the tank also has weak armor on top of the hull. Although I'm assuming it hit the main armor, the shockwave will diffract and also have an effect on the top of the hull.

...and what do basicly all MBT since the 1980(latest) have? Several layers of armour who will deform against each other. basicly any shockwafe runs itself dead...

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11 hours ago, Captain_Colossus said:

 

that is called a hellfire missile then. why arbitrarily choose a requirement for 8- why not go bigger and duplicate a maverick missile? the tow fills a gap for a lighter shorter range missile.  what would increasing the size and weight do that it isn't doing already which would merit the cost in weight that a person has to carry (for a larger warhead would mean a larger missile, which would change the requirements to adapt it for a new heavier launcher). where is the tow missile inadequate that a larger warhead is needed and where you essentially duplicate something which already exists? you're picking this larger figure, but why? what is the deficiency?

It doesn't have to be 8 kg, but I think 8 kg is enough to take the tank out of action.

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55 minutes ago, Grenny said:

...and what do basicly all MBT since the 1980(latest) have? Several layers of armour who will deform against each other. basicly any shockwafe runs itself dead...

In fact, I think the stiffness of homogeneous steel armor over 200mm thick would be large enough to prevent shock waves from being transmitted into the tank, where the real danger would be that the RHA armor would spall. Modern composite armor provides better protection against shock waves. But there are also parts of the tank hull with just tens of millimeters of RHA armor. 

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43 minutes ago, F.T said:

It doesn't have to be 8 kg, but I think 8 kg is enough to take the tank out of action.

 

adds nothing to the argument; again, missiles with larger warheads and larger range already exist. the tow fills a particular niche below a heavier missile like the hellfire as either a crew served weapon on certain vehicles, or standalone, or in the case of light recon / attack helicopters; furthermore, where do you get the idea that the TOW is necessarily inadequate- the top attack model for example doesn't rely on contact with the vehicle but fires a lethal projectile from above into the thin armor of the vehicle roof- does not require an 8kg warhead for that purpose

Edited by Captain_Colossus
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10 minutes ago, F.T said:

. But there are also parts of the tank hull with just tens of millimeters of RHA armor. 

Which are usually the parts that don't protect humans....so?

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16 minutes ago, Captain_Colossus said:

 

adds nothing to the argument; again, missiles with larger warheads and larger range already exist. the tow fills a particular niche below a heavier missile like the hellfire as either a crew served weapon on certain vehicles, or standalone, or in the case of light recon / attack helicopters; furthermore, where do you get the idea that the TOW is necessarily inadequate- the top attack model for example doesn't rely on contact with the vehicle but fires a lethal projectile from above into the thin armor of the vehicle roof- does not require an 8kg warhead for that purpose

I think you misunderstood my meaning. I have no doubt of TOW's power. I also have no doubt about the destructive power of an 8Kg charge. My initial question was whether an 8kg charge of high-explosive rounds could kill tank crew.

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9 minutes ago, Grenny said:

Which are usually the parts that don't protect humans....so?

Because the shockwave will diffract, the thin armor on top of the hull will be affected even if HE hits the main armor. Just don't know if the effect will be enough to kill the tank crew.

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10 minutes ago, F.T said:

I think you misunderstood my meaning. I have no doubt of TOW's power. I also have no doubt about the destructive power of an 8Kg charge. My initial question was whether an 8kg charge of high-explosive rounds could kill tank crew.

 

the problem is that you come back full circle. nothing explained matters because you already put the cart before the horse, it seems you already have the conclusion you intend in mind no matter what anyone says

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2 minutes ago, F.T said:

Because the shockwave will diffract, the thin armor on top of the hull will be affected even if HE hits the main armor. Just don't know if the effect will be enough to kill the tank crew.

Well, It doesn't, as there is not coupling between these identified armour weakspots and the turret roof...

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17 hours ago, Grenny said:

Well, It doesn't, as there is not coupling between these identified armour weakspots and the turret roof...

 

屏幕截图 2022-05-17 081930.png

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Well, there can be cases in which at least something similar could happen, like an explosion on the turret front right above the driver's hatch, or shockwave reflections. But these cases of impulse transfer are impossible to enumerate in a real-time simulation, and also resist stochastical approaches very well because so many variables are at play.

 

Even then, numerical methods have made great strides as predictors in armored vehicle design phases to see what constructive countermeasures reduce shockwave energy transfer (decoupled, flexing plates with air gap as the most prolific example) so that short of a direct impact, modern vehicles can be assumed to be better protected than ever against indirect effects. This was impossible to figure out experimentally before the mid 1980s when the finite elements method started to become practical (it's computationally very demanding).

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14 minutes ago, Ssnake said:

Well, there can be cases in which at least something similar could happen, like an explosion on the turret front right above the driver's hatch, or shockwave reflections. But these cases of impulse transfer are impossible to enumerate in a real-time simulation, and also resist stochastical approaches very well because so many variables are at play.

 

Even then, numerical methods have made great strides as predictors in armored vehicle design phases to see what constructive countermeasures reduce shockwave energy transfer (decoupled, flexing plates with air gap as the most prolific example) so that short of a direct impact, modern vehicles can be assumed to be better protected than ever against indirect effects. This was impossible to figure out experimentally before the mid 1980s when the finite elements method started to become practical (it's computationally very demanding).

Seen a test of several dozen kg vs M48.

The turret crew would have been dead...as the turret then rested 50m from the tank.

But the driver has pretty good chances of survival, the only thing applied to the driver station was the sudden acceleration of the whole vehicle upwards

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