Kinetic barriers vs modern weaponry

[Sarevok]

Suppose you have a kinetic barrier that stops moving objects. It can stop bullets and shrapnel very well.
However it can not stop radiation such light or heat at all. There is no effect on radiation at all, only physical matter is stopped.

The barrier distributes the momentum of the incoming round perfectly through the mass of the object it is protecting. So heavy kinetic weapon hits only move the protected object as opposed to punching gaping holes or outright shattering it.

There is one weakness however. Against an explosive weapon the barrier would stop the fragmentation and shockwave only. If it was a shaped charge then the cone would be unable to penetrate as well. But the heat from the explosion still passes through.

Say this technology was used to protect real world tanks and naval vessels. How damaging is the heat from an exploding missile or shell do ? FYI the barrier extends only a few centimeters from the surface of the armor.

So given this ability and the limitations therefore what would be the best way to defeat "shielded' ships and tanks made of real world materials ?

[Simon_Jester]

If the barrier performed as you advertise, I'm pretty sure anything shielded in this way would be nigh-invulnerable to anything other than nuclear weapons. Heat from an exploding artillery shell, in the sense of electromagnetic radiation that can "fry" a target, is practically nil.

About the best you could do would be, hm.

Play with thermobarics, possibly. Presumably the shield lets air through- which, OK, chemical weapons gain popularity again, in some applications... but anything that can be shielded like this can also be made NBC-resistant.

Where does the energy from particles striking the barrier go?

Do I have to provide power, joule for joule, to keep the shield from being knocked down? If so, it wouldn't be all that difficult to overload the things: indeed, any practical shield that could be installed on a platform smaller than a naval vessel, using modern power sources, could be collapsed by a hail of machine-gun fire. Supersonic antiship missiles would stand a pretty good chance of smashing through the shields of naval-sized targets too, assuming the barrier can't "store" large amounts of energy.

Do objects simply strike the barrier and bounce off in a perfectly elastic collision? In that case, the energy consumption of the shield might well be extremely small, making it far, far more difficult to bring down.

[Rabid]

If the shield is resistant to Kinetic energy but not impermeable to photons, maybe you should investigate the possibility that a Laser is more suited to do the job than a traditional hail of artillery shells or nuclear ordinances.

Sure, right now there isn't really a functional anti-ship laser. But I am very confident that by 2020-2030 you will begin to see 10 to 100 kW laser, maybe even more powerful ones, mounted on ships, as a test on anti-ICBM defense...


But today ? Against a target shielded like that ? Well, I hope you weren't expecting to save what is inside, 'cause it's time to bring in the Nukes. Less and you'd run the risk of expending tons, and tons and tons of ammunition for nothing, without counting all the occasion the enemy would have to destroy you while you are attempting your puny resistance.

Give it a good smash of coherent/concentrated high-energy photons, that's my best advice.

[Starglider]

Does this shield stop objects down to zero velocity? Does it work on fluids? What happens if we bomb a shielded object with napalm? Being covered in burning napalm is a problem for vehicles and particularly ships no matter how well armoured they are.

When you say 'no effect on radiation', what about neutron radiation? This is one of the main kill mechanisms for nuclear weapons against armoured targets.

[Simon_Jester]

If the shield is resistant to Kinetic energy but not impermeable to photons, maybe you should investigate the possibility that a Laser is more suited to do the job than a traditional hail of artillery shells or nuclear ordinances.

Sure, right now there isn't really a functional anti-ship laser. But I am very confident that by 2020-2030 you will begin to see 10 to 100 kW laser, maybe even more powerful ones, mounted on ships, as a test on anti-ICBM defense...

I wouldn't be entirely surprised, but said lasers won't do jack against a well protected target- at least, not compared to missiles and artillery fire.

[Sea Skimmer]

Reactive metal explosives will produce highly damaging levels of heat over a considerable radius much more so then normal HE as mass combustion of metals like titanium takes place. You’d need several hundred pound charges to really accomplish anything like this against a hardened target but say a 250lb bomb should still kill a tank, all the more so if delivered with high precision. Indeed a number of small smart bombs might still manage to disable a tank as fighting vehicle if they could hit the engine air intakes and the gun barrel. Ships could still cripple as ever from loosing radar and radio gear.

Shaped charges would also still work to a degree with any form of explosives or explosive effects; the earliest ones had no metal. Reactive metal is however very expensive for the moment anyway. Also something like a 120mm sabot hitting say, a hummve with this magic shield is still going to flip the thing over and this raises the question as to the shield making these things immune to fall damage?

[Korto]

Sounds like my best idea. Hit the damn thing with a big enough bomb so it flips over. It may be a heavy main battle tank, but it still looks bloody silly flat on its back with its tracks spinning in the air and shouting "Help! I've fallen and I can't get up!"

[Rossum]

Another time-honored tactic against shielded enemies: attack the ground its standing on!

In the case of navel vessels, it might be possible to sink them by setting off an explosion beneath the ships hull so that it creates an empty space below the ship and causes part of the ship to collapse downward due to the lack of water keeping it in shape. Note that I may be wrong on this, I heard that submarines are designed to operate with the outside water holding them together by pushing in on all sides so creating an area of low pressure below it causes the water around it to rush in and crush the submarine. Not sure if this same thing works on boats.


Or if its a tank then blow up the ground under it so that it falls into a hole, or flood the area its in with water, or spray some kind of hardening foam or a net or mud over it to reveal the shape of the shield and start burying the whole thing in garbage. Would a shielded tank be able to travel over a minefield? Could you send a whole bunch of little remote-controlled cars packed with bombs to run up against the edge of the shield, slowly slip through by going minimal velocity, and then blow up once they get past the shield?

Also, is the shield one-way or does it stop outgoing projectiles as well? If it stops outgoing projectiles then tank would likely have to drop part of its shield to fire its weapons.

Maybe have mines or explosives set up that launch dirt into the air to bury the vehicle or flip the vehicle over like Korto suggested. Dropping a decent sized (non nuclear!) bomb onto it from a plane or detonating one underground should create a big enough crater to slow it down even if it doesn't destroy the shielded object itself. Depending on how the shield's 'aura' reacts with the ground then the treads might still be vulnerable in which case you could try things like Dragons Teeth to thwart or steer the tanks into more favorable spots to blow them up.

If its possible for a human to cross the barrier (by moving real slowly through the shield or digging in the dirt to emerge under it when the tank come overhead) then I can imagine soldiers trying to get close to the tank to slap shaped charges onto the hull or in desperate situations become suicide bombers.

Plus there is the possibility of ramming it with a suitably heavy vehicle and trying to push it into a hole. Maybe a tractor or something depending on how heavy the tank is. Or you could get one of those helicopters with a magnet on the bottom, fly overhead, and turn on the magnet. I don't know if you can pick up a tank with a magnet and helicopter but the magnet might be able to screw with electronics inside the vehicle.

(just so you know, I'm listing all this stuff because I heard they have tests where you list various uses for a paperclip. People who do good can list twenty or thirty. The people who do really good ask if they can make the paperclip fifty foot tall and made of foam... or an inch thick, made out of soft bread, covered in salt and served with a cup of melted cheese.)

[Simon_Jester]

Another time-honored tactic against shielded enemies: attack the ground its standing on!

In the case of navel vessels, it might be possible to sink them by setting off an explosion beneath the ships hull so that it creates an empty space below the ship and causes part of the ship to collapse downward due to the lack of water keeping it in shape. Note that I may be wrong on this, I heard that submarines are designed to operate with the outside water holding them together by pushing in on all sides so creating an area of low pressure below it causes the water around it to rush in and crush the submarine. Not sure if this same thing works on boats.

...Huh?

No, explosions powerful enough to do things like that kill ships by shock waves. The blast from the explosion is transmitted through the water very well, much like sound in water. Water is (this is important) incompressible; it flows, but it doesn't squeeze. When an explosion hits near the hull of a ship, the hull of the ship is the most easily crushable thing around. The water acts to "tamp" the explosive against the hull, increasing its effective force because the power of the explosion has no other place to go.

You cannot create huge voids under water, large enough to break a ship's back by dropping it into them, with anything less than nuclear explosives. The water is, again, incompressible: it won't squeeze out of the way, so it has to be moved, and you're talking about moving thousands of tons of water a great distance to make this scheme work. I can't see it happening.

Or if its a tank then blow up the ground under it so that it falls into a hole, or flood the area its in with water, or spray some kind of hardening foam or a net or mud over it to reveal the shape of the shield and start burying the whole thing in garbage.

This last is clever, but you need pumping equipment and such nearby to pile on more junk, and the tank will probably have little trouble shooting you full of holes. The first is not so clever; one of the things tanks were invented to do is climb out of shell holes.

Would a shielded tank be able to travel over a minefield?

I like this one.

For ideas like this, a lot depends on whether the shield is maintained on the parts of the object in contact with water or the ground. If the shield doesn't extend underwater on ships, hit it with torpedoes and break it in half from below; if the shield doesn't extend underground on tanks, trying to maneuver them into a minefield is one of the more cost-effective things you can do to them.

Could you send a whole bunch of little remote-controlled cars packed with bombs to run up against the edge of the shield, slowly slip through by going minimal velocity, and then blow up once they get past the shield?

Hmm. Interesting.

Maybe have mines or explosives set up that launch dirt into the air to bury the vehicle or flip the vehicle over like Korto suggested. Dropping a decent sized (non nuclear!) bomb onto it from a plane or detonating one underground should create a big enough crater to slow it down even if it doesn't destroy the shielded object itself.

Conceivable, but you need a really big bomb to create a crater big enough to stop a tank. Big enough that dropping it close enough will probably flip the tank over anyway by momentum transfer.

Plus there is the possibility of ramming it with a suitably heavy vehicle and trying to push it into a hole. Maybe a tractor or something depending on how heavy the tank is. Or you could get one of those helicopters with a magnet on the bottom, fly overhead, and turn on the magnet. I don't know if you can pick up a tank with a magnet and helicopter but the magnet might be able to screw with electronics inside the vehicle.

...The average tank weighs fifty to seventy tons and is a Faraday cage. It's also armed with a cannon that can blow the shit out of your pusher vehicle- this makes a lot of tactics less practical than they might be. Helicopters in particular are going to be vulnerable to anti-air weapons while hovering over an enemy tank with a huge magnet.

[Rabid]

About shield-protected ships :

Would an under-the-keel explosion work ? I mean... Does the shield act as a kind of “exo-skeleton” (“holding the ship together”) for the shielded object, or is it more akin to some sort of “skin” (just adapting its shape to the shape of the object) ?

Because, if it acts more like a “skin”, if we can trust what is said there, then we can deliver some sever damages to a shielded ship with already existing torpedoes.

[Simon_Jester]

Hmm. I think I was wrong about the practicality of creating 'voids' to drop a ship into; I was thinking in terms of older torpedoes, not modern under-keel designs.

But if the shield had substantial 'flex' to it, it wouldn't be effective as a defensive system in general; it'd just crumple up in response to an impact. To make things bounce or splatter against the shield while shoving the entire object sideways like a single extremely rigid body, the way it's described, I'm pretty sure the shield would have to act as an exoskeleton.

[Rabid]

To make things bounce or splatter against the shield while shoving the entire object sideways like a single extremely rigid body, the way it's described, I'm pretty sure the shield would have to act as an exoskeleton.

Which leads me to think that if you where able to somehow apply pressure on 3 different points of the structure so that the ship would normally be cut in two part (1 point of pressure under the keel, directed upward, and 2 points of pressure on the bow and stern, directed downward), if you were to put enough energy in it, the shield could maybe beak :

If I understand the OP correctly, for ONE point of impact, it spread the effort on the whole shield, in the same direction. But if you simultaneously apply several points of pressure with different orientation, maybe it could put sufficient stress on the shield to "break" it... I don't know. Intuitively that seems right, if you want to conserve energy and momentum, but we are dealing with some sort of magitech here, so...

[Ellindsey]

Does the shield generator obey newton's first law? If you push on the shield, is the force transmitted to the shield generator? If it doesn't, you can use the shield to produce reactionless thrust, which opens a vastly larger can of worms. If it does, then a really strong impact on the shield might tear the shield generator off its mountings or physically smash it through momentum transfer.

[Aleva13]

The OP stated that the momentum is transfered to the entire protected object.

[Rossum]

One other thing is that if the shield transfers all the energy in one direction then explosions hitting it will have more of their energy going in one diretion than otherwise. So if a bomb hits a regular tank then it would launch the tank in thousands of different directions each with a fraction of the energy, hitting a shielded tank would have the same tank get all that energy pushing it in one direction (or pushed outward away from the tanks shield). So anti-tank mines triggered by the tank would convert more of their enrgy into launching the tank upward or making craters.


Also, if the shield is surrounding the tank by a few centimeters then its probably creating an outline of the tanks main cannon. If the main cannon moves to aim and the shield follows it... then there might be some kind of weakness there. I don't know how leverage factors into this magical shield but the cannon could be a weak point somehow.

Speaking of which: Is there a way to ruin the barrel of a tank cannon in a semi-efficient manner? I mean in Indiana Jones and the Last Crusade, Indy was able to destroy a tank barrel by sticking a rock in it before it fired. I'm sure the shield around the tank would provide lots of protection but is something can get through or rhe shield can be magicall reverse polarified then taking out the gun could do some good... maybe a cloud of acid or spraying quick-hardening cement or something to where it might get inside.


Or, if you can't destroy the tank then try to blind it by filling the area with smoke or radio/radar noise to slow it down. Maybe find a way to destroy its sensors somehow.

[Balrog]

I'd have to echo Simon's original questions. Is there a limit to the amount of kinetic energy that said barrier can stop? Will it get overloaded if you hit it enough times, if you hit it multiple times in a given time frame, if you hit it from more than one direction? Is it dependent upon the vehicle itself in some form or another for its protective ability, i.e. a small scout car doesn't enough enough power to give it the same amount of protection as a big tank with a larger power source?

And if you aren't trying to shamelessly steal the idea from Mass Effect, who are you debating against?

Since the OP said momentum is transferred throughout the entire vehicle, I imagine for something light like a humvee that powerful impacts from something like a tank cannon would still cause significant damage to the structure, or at least knock the damn thing over on its side, even if it could perfectly absorb the kinetic energy of the round with no ill effects.

[Simon_Jester]

One other thing is that if the shield transfers all the energy in one direction then explosions hitting it will have more of their energy going in one diretion than otherwise. So if a bomb hits a regular tank then it would launch the tank in thousands of different directions each with a fraction of the energy, hitting a shielded tank would have the same tank get all that energy pushing it in one direction (or pushed outward away from the tanks shield). So anti-tank mines triggered by the tank would convert more of their enrgy into launching the tank upward or making craters.

...?

I don't even understand what this means. Why would a bomb transfer more momentum to a shielded tank than to a normal one?

Speaking of which: Is there a way to ruin the barrel of a tank cannon in a semi-efficient manner? I mean in Indiana Jones and the Last Crusade, Indy was able to destroy a tank barrel by sticking a rock in it before it fired. I'm sure the shield around the tank would provide lots of protection but is something can get through or rhe shield can be magicall reverse polarified then taking out the gun could do some good... maybe a cloud of acid or spraying quick-hardening cement or something to where it might get inside.

It would be really freaking hard to deliver something like this.

[DudeGuyMan]

Are there openings for treads to touch the ground, propellers to touch water? Or are they surrounded as well and it's actually the shield pushing against the environment?

[LaCroix]

I don't even understand what this means. Why would a bomb transfer more momentum to a shielded tank than to a normal one?

Because it is bullshit. The amount of energy would be the same, just the outcome would be different. E.G. for the bomb: instead of a gazillion high speed small parts flying, you will have a fully shielded Tank set 1 feet deep into the ground by the 'push'. The mine would make it hop one feet up instead of blowing it apart. (All these measurements are an example, as I don't have any data on the force of a "bomb" or "mine")

It would be really freaking hard to deliver something like this.

Well, it's rather easy. Conceal your self, wait until the tank drives by. Then jump up, yell "surprise", and while they stare stupidly at you, you nail them down the barrel with a bazooka...

For the other variants, I propose chlorine trifluoride or quick hardening PU foam. Both will definitely mess up a barrel....

[Simon_Jester]

Are there openings for treads to touch the ground, propellers to touch water? Or are they surrounded as well and it's actually the shield pushing against the environment?

If so, geometry will be a bitch to do on the propeller blades. Propellers on a ship (or an airplane, for that matter) have to be shaped very carefully; building a shield with the right shape to cover it, equally so.

Honestly, yes, so much of how to counter something like this depends on the details that the question as posed in the OP is unanswerable. It's like asking "how do I fight things made out of metal?" without specifying whether the "thing made out of metal" is a tank, a submarine, or a supersonic jet.

[Rossum]

[quote="LaCroix]Because it is bullshit. The amount of energy would be the same, just the outcome would be different. E.G. for the bomb: instead of a gazillion high speed small parts flying, you will have a fully shielded Tank set 1 feet deep into the ground by the 'push'. The mine would make it hop one feet up instead of blowing it apart. (All these measurements are an example, as I don't have any data on the force of a "bomb" or "mine")[/quote]

Yeah, that's what I meant to say. The energy is the same but having a shielded tank changes how much of it goes where. Not sure how this could be turned into an advantage by an attacker but I figured I could point it out.

[Simon_Jester]

I'm not really sure how much difference it makes in terms of momentum transfer. It depends on how the shield behaves, and other such details.

[Connor MacLeod]

I don't think anything short of a beam weapon would penetrate. Even "heat" weapons (I feel compelled to point out heat is a property not a "radiation") won't neccesarily penetrate - stuff like flamethrowers will be repelled because the thermal component is phyiscal matter (it sticks to the target and burns.) and even explosive shockwaves are really just expanding, high temperature gasses (they have mass and velocity and would also be stopped.)

The only way the above would not be true is if the shield is somehow magically conducting the heat to the target, or that the barrier is interwoven into the hull material (basically contact with the barrier is contact with the hull, or near enough as to make no real difference.)

I'm also having to wonder at how this hypothetial barrier interacts with the physical structure. I mean what happens if a massive boulder is dropped on top of a tank? Sure it stops dead when it hits the barrier, but you still have gravity and a bigass rock acting on it. Even if the barrier doesn't go down, does that mean that the internal (solid) structure can resist infinite impacts? What about small components? will anything get wrenched out of place if too much force is applied (with potentailly hazardous results) or does the hypotehtically magical kinetic barrier provide perfect structural reinforcement as well?

There's also the acceleration issue. I assume that the barrier is meant to smooth out stresses on the hull, but does it act like an inertial damper as well? Otherwise there's quite a good possibility that anything inside the vehicle will be subject to violent accelerations (Eg crew) which could be a possible way to "kill" it.

[someone_else]

Say this technology was used to protect real world tanks and naval vessels. How damaging is the heat from an exploding missile or shell do ? FYI the barrier extends only a few centimeters from the surface of the armor.

Very little. Most chemical detonations transmit the vast majority of their energy through the particle's kinetic energy that becomes heat only on impact.

The barrier distributes the momentum of the incoming round perfectly through the mass of the object it is protecting. So heavy kinetic weapon hits only move the protected object as opposed to punching gaping holes or outright shattering it.

And if you say it transmits momentum to the whole vehicle's mass... you cannot topple it without excavating the ground beneath, nor push it with murderous accelerations to kill the crew.

So given this ability and the limitations therefore what would be the best way to defeat "shielded' ships and tanks made of real world materials ?

A big walking mecha with arms. You take up the goddamn vehicle and throw it in the nearest pond, or play soccer with it until they surrender. It's not like it can kill you without ludicrously overpowered energy weapons or nukes either.

Really, a shield like this would make obsolete anything unable to carry nukes.
Lasers tend to be heavy and short-ranged (in the atmosphere) and also easy to avoid (in the atmosphere you can fill everything of smoke, in any theater you can place whipple shields to exploit the 20:1 penetration/spot_size ratio of weapon-grade lasers, forcing your enemy to pack truly hellacious weapons to have any chance of damaging you).

[mithie]

If none of the kinetic energy is lost on the shield but rather ends up evenly distributed against the hull, then I can see a high yield directional (downwards) air-burst weapon being effective.

The shockwave would slam the shield hard, and crush the hull against the earth.

Hell; a direct top hit from a 16 inch arty shell should mission-kill any modern armor protected by the shield; even if the hull isn't flattened, the crew would be dead.

And if you say it transmits momentum to the whole vehicle's mass... you cannot topple it without excavating the ground beneath, nor push it with murderous accelerations to kill the crew.

Why not? If you slam the top of the vehicle, you'd still be applying a net downward force against the hull.

If you slam hard enough, you'd crush the hull like a coke can under a steel boot. Force distribution means nothing when your foot is bigger than the can.