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Applying pressure for clearing land mines

  1. Apr 29, 2016 #1
    Hi, Im a Industrial Design student working on my senior Thesis. Since antipersonal landmine cleareance is a very dangerous process; im working on a remote controlled vehicle concept that will be able to do a controlled detonation. That way the human wont have to manually disarm the landmine which is the current dangerous and slow process. Basically to detonate a landmine you need no more than 10 pounds of pressure. The only thing I can think of is compressed air, but obviously is a problem to have those compressed air tanks next to a explosion, even if is controlled.
    Or maybe im mistaken?
    Any Help would be greatly appreciated
     
  2. jcsd
  3. Apr 29, 2016 #2

    berkeman

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    Welcome to the PF.

    What has been used in the past for doing this? How are you going to improve on existing technologies?

    http://2.bp.blogspot.com/-poBh5X4vP...k/s1600/USZ+Mine+Sweeper+Tank+(Mine+Wolf).jpg
    USZ+Mine+Sweeper+Tank+(Mine+Wolf).jpg
     
  4. Apr 29, 2016 #3

    Baluncore

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    As pictured above, the reliable technology was developed 75 years ago. https://en.wikipedia.org/wiki/Mine_flail
    On solid ground, the flail will give a very high clearance confidence at a very low cost of consumables.

    The relative cost to the enemy of the original mines and the cost of mine clearance to the survivor is not important. The problem should be resolved safely for minimum cost. A pneumatic actuator would be quite expensive if it was destroyed each time a mine was found. If the location of the land mine is known then it can be counter-mined with a small explosive charge. That can be arranged to give the best probability of cutting the trigger mechanism from the mine, possibly without detonating the main charge. An alternative would be to use something like a shotgun to apply the pressure to the mine. A heavy shotgun barrel will survive the detonation of the mine.

    In soft ground such as a swamp or rice paddy, the mines may circulate up and down until it may be triggered at the surface years later. Where stray land-mines may have surfaced, a dense herd of goats or sheep are driven through prior to planting. The cost and probability of killing an animal is small, but it can still feed the village. The small area of hoof that does so much damage to the land while grazing increases the ground pressure needed to trigger a mine.
     
  5. Apr 30, 2016 #4
    Thank you guys so much for the info.

    I have looked into those big deminer trucks, the problem is the logistics to move them from one country to the other makes them very expensive, the other issue is that you have very uneven terrain with small paths where they dont fit and they will highly damage the ecosystem. They are mainly used to clear a specific path so the military demining, im focusing on humanitarian demining.
    Yes, the location will be known, the rc car that Im designing will work cooperatively with a Drone that have a ground penetrating radar to locate the landmines (they use those already in archeology). So basically the drone will scan a suspected area and will pin point the specific spots where landmines are located, and this ground car will detonate them almost like a controlled explosion, Landmines dont have big amounts of explosive, around 1 pound, so thats why I think it can be contained, Im just stuck on how to make them detonate. Im leaning towards a small explosive that is strong enough that will make the landmine detonate.
     
    Last edited: Apr 30, 2016
  6. May 3, 2016 #5

    CWatters

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    Perhaps some sort of fuel air explosion could create enough downward pressure or are they immune to pulses of pressure?
     
  7. May 3, 2016 #6

    jim hardy

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    Pressure ? Over what area ? Or did you mean force ?

    I'd drop a gallon jug of water on it from about three feet. The water will not become a dangerous missile.
    Or use water instead of compressed air to deliver the force of your small explosion.
     
  8. May 3, 2016 #7
    Unless you know exactly where the mine is located compressed water may only serve to uncover, dig up and or displace a landmine without detonation.

    Perhaps a solid metal roller (Like on a steam roller maybe smaller) set on a long "spring arm" a good distance from a blast shield, not sure how well something like that would hold up to an explosion, BUT if it could absorb the blast by bouncing off the ground, you could make it as wide or as slim as you need it as long as you have a power plant capable of pushing the weight and a way to steer the roller around corners.

    Just a thought :smile:
     
  9. May 3, 2016 #8

    jim hardy

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    I assumed he found the approximate location by drone and zeroed in on it with a magnetometer mounted on his RC vehicle (Sears riding lawnmower ? )
    and he knows its location precisely enough he could hit it with a sledgehammer on a long arm if he wanted to
    the water jug idea is just to prevent flying sledgehammers .

    Might be a bad assumption on my part ....

    the question as i understood was 'how to safely apply 10 pounds of force to a landmine trigger without generating dangerous flying pieces of the applicator'
    what immediately popped into my alleged mind was:
    "Place a plastic milk jug full of water on it and set off a blasting cap* inside the jug" (*Can't buy cherry-bombs anymore)

    but dropping the jug from above might work as well

    just brainstorming...
     
    Last edited: May 3, 2016
  10. May 3, 2016 #9
    I was commenting to the compressed water idea, i was thinking spraying water like out of a hose... the milk jug idea would work if you could hit it on the trigger mechanism. Spraying water i think it would spread the force out in all directions (as would air) on something buried a couple inches under ground. That is unless you had a precision water cannon or air gun and it would probably have to be right on top of the mine. Perhaps a large caliber firearm, as has been suggested mounted on a bomb disposable robot. There is a round called a ( breaching round) or a (plug round) that if you could get within 2 feet you could shoot the mine....it should have the power to either detonate the mine or render it inoperable. A milk jug full of water would have a "tamping" affect and would be a competing force with the blast going up and the water trying to go out. Could possibly even limit the mines blast radious actually. A milk jug with a blasting cap may have the ablity to render the mine inoperable as well do to the directional tamping force.
     
    Last edited: May 3, 2016
  11. May 3, 2016 #10
    Just to clarify my vision would be a solid steel rolling cylinder on a long spring loaded arm mounted to the front of a small vehicle with a blast sheild to protect the vehicle, heavy enough to detonate the mine, but tough enough not to turn to shrapnel and springy enough to absorb the blast. But then again i was thinking reusablity. Small enough to transport manuverable enough to turn corners and able to go over rough ground.
     
  12. May 3, 2016 #11

    Baluncore

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    There is no need to be sudden when clearing a landmine. For example, you could drill into a plastic mine with a solid “unicorn horn” or “screw extractor” shaped drill, then if the mine had not detonated, pull back to lift it out of the ground. It would not matter where you penetrated the mine, or how the trigger was rigged, it would either detonate or not. Either way you have removed it from the ground.

    I suspect that in any one minefield, the number of models of mine being cleared will be limited. Each type of mine will have some sensitive primary trigger. Once those trigger mechanisms have been identified it will be easier for an autonomous vehicle to reliably trigger or lift that design of mine with minimum resources. You might also expect to find one mine laid on top of another somewhere in the field, or possibly a booby-trap trigger to cripple a mine clearance officer. Your vehicle should be designed to survive that event, or at least provide some evidence as to what was abnormal prior to it's destruction.

    When a mine is triggered, the ground provides a reasonably solid backing, so all the energy will be radiated upwards into the air above, which is how it was designed to work. Any confinement above is liable to increase shock-wave pressure and at best, could only reflect half the air-blast into the Earth. For that reason the clearance mechanism needs to be both “sparse” above the landmine, and mine type specific in it's approach.

    The idea that mine clearance equipment will need to be moved more than once, is wishful thinking. The equipment should be multiple, cheap and replaceable. It will be abandoned when it's job is done, or when the accumulated injury / damage is beyond repair.
    The flail tank is expensive but has a high probability of survival. A goat is cheap but has a zero chance of survival. A mine clearance automaton needs to clear mines somewhere near the minimum cost per mine. Finding that minimum is a design challenge.
     
  13. May 3, 2016 #12

    Baluncore

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    What if the mine is located between two rocks? The roller will ride over the rocks and so not trigger the mine.
     
  14. May 3, 2016 #13
    ..

    True...there would be drawbacks to anything you would use for this purpose, Damage to a clearing device, places where you couldn't use it, flying goats.
    BUT if you could locate mines with such precision you could simply use a sniper rifle and take them out like target practice. And how acurate a picture can you get from GPR....would a 50 year old mine be identifiable? From the air with this technology? There are many approaches....which one is full proof?
     
  15. May 3, 2016 #14
    Again to clarify.....these are just questions that must be considered. This young man's engineering idea is both noble and very much needed in some parts of the world. And if successful would save lives.
     
    Last edited: May 3, 2016
  16. May 23, 2016 #15
    I've seen dogs and rats being used to sniff out areas where there are land mines, one person collects an air sample from a certain area, and then dogs sniff the samples to see if there are any traces of explosives. I am not sure what exact explosives they are trained to smell though..

    Another thing Terahertz Spectroscopy, and some relatively new and quick ways of using this to scan / find "fingerprints" of certain chemicals used in explosives. Here is an article about it:

    http://phys.org/news/2016-05-speedy-terahertz-based-explosives.html

    I do like the solid steel barrel idea, but yeah what if there are rocks or something else. Maybe it can be a skewed barrel like how a drill bit looks like, that would maybe help with the dispersion of energy after the mine is triggered. To save weight with transport, maybe make it hollow and fill it up with water / sand when in use? Though the shell has to be quite tough to withstand the explosion (though I guess not that tough if they are anti-personell mines). I know depleted uranium is quite tough and resistant to explosions (the US military uses this on their Abrahm tanks, along with explosive reactive armour). There is also something called Composite Metal Foams (CMF) which have quite impressive armour protection, you can read more about it here:

    http://phys.org/news/2016-04-metal-foam-obliterates-bullets.html

    I'm no expert on this, but I would presume that finding ways to locate many different types of mines, for large diverse areas, in a relativiley easy / cost effecient way is the best bet. Once mines are located, then there are many ways to detonate / get rid of them. Maybe for now smell is the best option, and hopefully later in the future more advance types of spectroscopy.
     
  17. May 23, 2016 #16
    Yeah I would use small explosives to detonate them, like an upside down claymore or some other simple shaped charge.
     
  18. May 23, 2016 #17

    Baluncore

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    Unfortunately DU is a toxin. https://en.wikipedia.org/wiki/Depleted_uranium#Health_considerations

    If the device will be used repeatedly in a minefield it is important that damage is not quickly accumulated. I suspect that metal foams will be expensive and quickly damaged by the products of the mine explosion.

    Ideally a mechanical triggering device should be massive and survive the detonation. But that requires an actuating vehicle to be close at the time of the mine explosion.
    It could be something like a thin conical sheet of explosive that does not produce shrapnel. The advantage of a light weight explosive is that it can be detonated remotely, which will reduce damage to the remotely controlled vehicle by the landmine detonation.
     
  19. May 24, 2016 #18

    JBA

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    In the oil industry small (1/2" dia x 3/4" long) cylindrical shaped electrically fired well casing perforating charges (with a conical depression in one end to direct and concentrate the blast force) that do not damage the down hole charge carriers, have been used for many years. They function in the same manner as the shaped charges that are used in the should fired missiles used to penetrate military tank armor.

    (Note: For those not familiar with petroleum drilling and production operations, a number of these charges are placed around a cylindrical steel carrier lowered into a drilled well on an electrical cable to the depth of the oil containing formation where they are then fired to create a carrot shaped hole through the steel casing wall, its surrounding cement liner between the casing and surrounding formation and into the oil producing formation. It is these holes that allow the oil/gas in the formation to enter the well bore and be produced from the well.)

    In construction site ground detonations reusable blasting mats of woven wire rope are laid over the blasting areas to control surface debris while still allowing venting of the explosive gases through the mat to minimize its damage.

    In your system, where the location of the mine is already accurately determined, possibly a combination of these two items combined with a remote controlled wheeled vehicle to place the assembly over the mine would create a cost effective solution. (The charge should be inserted into the lower face of a thick steel plate in the center of the circular mat to effectively direct the blast force downward toward the mine.)
     
  20. May 24, 2016 #19

    Baluncore

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    Such a steel plate will also trap the energy from the detonating mine between the plate and ground. That will result in more side-blast and shrapnel being directed to damage the trigger vehicle.
    A heavy steel cover plate can only double the initial trigger blast towards the mine. It would be better to double the small mass of explosive used for the trigger. The mass needed for a cover plate could be better allocated to a woven blast mat that would distribute the energy over time and space rather than concentrate it.
     
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