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Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

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Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#101

Dr Alford also designed water-lined shaped charges for disrupting IEDs - https://en.wikipedia.org/wiki/Sidney_Alford#Early_Inventions

Am I reading this right? That section also says he made shape charges out of cucumber that could cut steel!

You read that right or we're both reading it wrong. I'm guessing the cucumber was an early prototype of the gelled water shaped charges, or he has a very...energetic...hatred of salads.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#102
post #20

Earlier quoted context omitted.

Update: 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…

It’s not molten, and heat plays no role in the penetration ability. This is a very common misconception. It’s simply focused kinetic energy that does it. The cone focuses the copper into a slug like object, and the slug becomes similar to an extremely powerful bullet.

What would happen if you just started with a slug?

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#103
post #99

Earlier quoted context omitted.

Count the fingers. More than 8 is probably OK. age may be a drawback, one gets too old to meddle with some of the more fun things eventually.

There are old people who use explosives. There are bold people who use explosives. But, there are no old, bold people who use explosives.

Reading Ignition! convinced me that there's more than raw intelligence to experimenting with energetic chemistry. https://www.amazon.com/gp/aw/d/0813595835/

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#104
post #47

Earlier quoted context omitted.

HEAT warheads (what NLAW has) is completely to do with shaped charges.

Yes, but it is not how it is used in Ukraine. Quote: "Against tanks and other armoured vehicles, the overfly top attack (OTA) mode is used; the missile flies about one metre above the line of sight, detonating the warhead above the target's weaker top armour". It has dual-mode: direct attack and OTA. The many tanks in Ukraine are killed in OTA, that does not use the shaped charge effect.

Yes it does. There're various decent explanations and videos of how both modes work.

To quote from SAAB's own website: "Our NLAW system is a easy system to use. Watch this video to see how it uses PLOS (predicted line of sight) and OTA (Overfly-top-attack) to enable its powerful shape charge warhead hit the tank at it´s weakest point - the turent. Maximising the potential damage to the tank."

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#105
post #41
post #7

If you're going to play around with explosives, an old knowledgeable teacher is best. I imagine incompetence gets weeded out early. The guy in the video has been in quite a few others too. It's fun to see how the hosts are usually a little nervous and he's calm as can be.

"What makes me a good Demoman? Well if I were a bad Demoman, I wouldn't be sitting here discussing it with you, now would I?" One of the silliest, hilarious but on point thing I've ever heard uttered from a video game character

Survivorship bias personified

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#106
post #91
post #7

If you're going to play around with explosives, an old knowledgeable teacher is best. I imagine incompetence gets weeded out early. The guy in the video has been in quite a few others too. It's fun to see how the hosts are usually a little nervous and he's calm as can be.

The younger guy in this clip actually ended up retiring because he got brain damage in a contraption he designed for this show. https://www.bbc.com/news/uk-58762935

> The injuries happened when Mr Stansfield, who was 42 at the time, filmed a Bang Goes The Theory feature about the relative safety of forward and rear-facing child car seats.

> The episode saw him "strapped into a rig like a go-cart which was propelled along a track into a post".

I'm sorry but to me this reads like something out of Darwin Awards.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#107
The Wikipedia article on shaped charges is fascinating:

https://en.wikipedia.org/wiki/Shaped_charge

The penetration distance is proportional to the diameter of the charge (counterintuitive; you'd expect the height), and can be up to 7x as large. So a ~5 inch charge shown in the film can penetrate up to about 3 feet of solid steel.

Also, all of our known defenses against shaped charged rely on the assumption that the same spot won't get hit twice. Composite armor breaks and deflects the geometry of the jet through its deformation; reactive armor relies on a mini-explosion to defeat the jet. This has interesting implications in a world of drones and precision-guided munitions, and in fact the Javelin missiles we've been shipping to Ukraine have double warheads, the first to destroy the armor and the second to destroy the vehicle.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#108
post #38
post #16

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?

Sorry 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…

Imagine 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.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#109
post #41
post #7

If you're going to play around with explosives, an old knowledgeable teacher is best. I imagine incompetence gets weeded out early. The guy in the video has been in quite a few others too. It's fun to see how the hosts are usually a little nervous and he's calm as can be.

"What makes me a good Demoman? Well if I were a bad Demoman, I wouldn't be sitting here discussing it with you, now would I?" One of the silliest, hilarious but on point thing I've ever heard uttered from a video game character

The bad demomen had to be glued back together. In hell.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#110

Earlier quoted context omitted.

Here's a vid I found that seems to show a simulation of the effect: https://www.youtube.com/watch?v=CpVVGk2OfQQ

It appears to rely on the copper’s ductility. Curious if a gold or silver shaped charge has been modelled.

It's been used for plutonium. The explosive lenses used in implosion-type nuclear weapons are extremely-precise shaped charges, and work by focusing all the explosion's energy into compressing the plutonium down to critical mass:

https://en.wikipedia.org/wiki/Explosive_lens

https://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosio...

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