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I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it th
by daenz 4y ago
I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?
- emmelaich 4y agoA major part of it is that the copper is going extremely fast. But also see other explanation, about being renewed.
- trhway 4y agodue to the copper cone shape and the explosion wave propagation from the back the copper, which at those pressures is flowing like a liquid, is formed into a jet and pushed forward like a water in a power washer hose. Water at 3000bar would cut several inch steel (https://www.youtube.com/watch?v=quL14Csmi_Y https://www.youtube.com/watch?v=quL14Csmi_Y). The copper in that explosion gets accelerated to the speeds of like 10km/s and as a result cuts through everything in its way. A bit of current context - beside deep penetration the jet isn't that destructive to surroundings. And here comes design flaw of Russian tanks - getting inside a Russian tank such jet frequently hits the tank's ammo which in those tanks is stored in a carousel around/under the turret and thus it results in the whole tank ammo explosion which even throws the multi-ton turret several stories up into the air (you can see a lot of the tanks blown up in that way - 'lollypops' - in Ukraine). To compare - US Abrams tank has ammo stored in separate compartment in the back of the turret.
- KennyBlanken 4y agoFYI, waterjets cut by using water to carry an abrasive media which is injected into the stream at/near the nozzle, not by the action of the water alone.
- jacquesm 4y agoYou can use an abrasive component but you don't have to, pure waterjet cutting works. And depending on the materials and the nozzle shape might actually be the optimum.
- Someone 4y agoAlso crucially, the munitions compartment is weaker on the outside of the tank than on the wall between it and the crew, so if it goes, it blows out of the tank (search term “blowout panels”) Fireworks and ammunition factories and storage facilities tend to have strong walls and relatively weak roofs for the same reason: if a building goes boom, you don’t want it to make neighboring buildings go boom, too.
- nine_k 4y agoUpdate: this is incorrect. The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice. This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment easily. Various kinds of "active armor" trigger the munition by a thinner layer of metal well ahead of the real thick armor plate, then produce counter-explosions to break the jet.
- raldi 4y agoThe video specifically says it’s not molten.
- causality0 4y agoIt's not actually liquid, it only behaves like one on impact due to the magnitude of the forces. It's more accurate to say it erodes through the armor instead of melting.
- Vladimof 4y ago> much like a jet of hot water melts through a block of ice cold water can cut through steel also...https://www.youtube.com/watch?v=v0NVOThRooE https://www.youtube.com/watch?v=v0NVOThRooE
- Nextgrid 4y agoWaterjet cutting uses water to propel a powder which acts as an abrasive, like an infinite stream of sandpaper. I don't think water by itself will achieve much.
- Vladimof 4y agoyou learn something new everyday
- climb_stealth 4y agoHuh, thanks for mentioning this! I always thought it was just water with enough pressure. It looks like pressure cutting with pure water exists but it is limited to softer materials. This page [0] has a fair bit of detail on it all. [0] https://www.machinemfg.com/waterjet-cutting-guide/#Classification_of_waterjet https://www.machinemfg.com/waterjet-cutting-guide/#Classific...
- daenz 4y agoSorry to answer my own post, but I watched it again and picked up on the key idea at 2:09. The inverted apex of the cone drives into the steel, pushing the steel aside, but then the apex opens up and flows back along the outside of itself. In other words, any given part of this copper "wire" interacts with the steel only long enough to push it open, then it is replaced by new copper. From this explanation, it sounds like the tunnel that has been "bore" through the steel would be completely coated from start to finish by the inverted copper cone.
- lamontcg 4y agoThe mental image which is working well enough for me is a series of tightly packed bullets with each one digging the hole a little deeper than the last one. Of course the shaped charge isn't a gun though and the stream of copper doesn't travel for hundreds of meters/yards. If you need to stand off from the target you'd want to mount it as the payload of a rocket and fire towards thine enemies. EDIT: this is of course a better description: https://www.globalsecurity.org/military/systems/munitions/bullets2-shaped-charge.htm https://www.globalsecurity.org/military/systems/munitions/bu... So the rod is traveling so fast that it and the target act like liquids, even though it isn't molten.
- colechristensen 4y agoImagine a picture of the jet coming out of a black hole. Something very roughly similar is happening here. The shape of the cone as the detonation wave goes through the explosive forces copper into the center and the only (or lowest resistance) way out is a straight jet through the target material.
- davesque 4y agoHere's a vid I found that seems to show a simulation of the effect: https://www.youtube.com/watch?v=CpVVGk2OfQQ https://www.youtube.com/watch?v=CpVVGk2OfQQ
- daenz 4y agoGreat find @ 0:40. The only thing it doesn't convey very well is the older man's explanation of the copper spear curling outward on itself. From the simulation, it seems like it is just punching through and maintaining its rigidity somehow.
- jvanderbot 4y agoiirc, nothing is rigid, it's just very high energy jets, so they don't deform much. like particles in water jets cutting steel.
- itsyaboi 4y agoFun fact: water doesn't actually do the cutting, the water is just a medium for carrying an abrasive dust (ruby/sapphire/diamond) that abrades the steel.
- CapitalistCartr 4y agoWe use 80 mesh garnet.
- JumpCrisscross 4y agoIt appears to rely on the copper’s ductility. Curious if a gold or silver shaped charge has been modelled.
- shirleyquirk 4y agoI found https://apps.dtic.mil/sti/citations/ADA278191 https://apps.dtic.mil/sti/citations/ADA278191 which has this to say about gold: >Hypothetical shape charge liner. High density is a benefit but equally low speed of sound indicate s that it may be no better than uranium. An advantage may be found in its ductility, if it leads to greatly improved jet formation relative to its cost. It seems that sound speed and density are considered more valuable, so tungsten, zirconium, molybdenum.
- yread 4y agoIt's not molten but it could be and it would still work as the guy in the video invented water-lined shaped charges (for disabling mines and IEDs without making them explode). What's important is the force/pressure that pushes steel to the side.
- nabla9 4y agoThe velocity of the jet is typically around 10 km/s. There is enough pressure to get trough.
- askvictor 4y agoI'm impressed (and a little confused) at the idea the explosive is essentially sitting untethered on the target. I would have thought the entire contraption would shoot up with the explosive force being reflected off the ground, but I suppose there's enough energy in the initial blast (before the reflection) to form the copper 'bullet'. =
- lazide 4y agoThe reason it works is nothing has time to get out of the way - all this is well past the speed of sounds for all materials involved. So the action/reaction is happening - the gas from the explosive is recoiling for instance - but it only has time to go a few inches and the forces and counter forces are immense.
- ycombinete 4y agoIt functions more like a jet of water. The speed that the solid copper moves at pushes the steel aside as if the were both liquids