3 ms·

Here'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 ago
Great 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 ago
  iirc, 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 ago
    Fun 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 ago
      We use 80 mesh garnet.
JumpCrisscross 4y ago
It appears to rely on the copper’s ductility. Curious if a gold or silver shaped charge has been modelled.
- shirleyquirk 4y ago
  I 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.
- nostrademons 4y ago
  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/Explosive_lens https://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosion-type https://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosio...
BurningFrog 4y ago
Aha! So the shape is such that all parts of the cone converge at the center, so the full energy of the explosive is focused in that thin column.
jacquesm 4y ago
The time scale on those is very interesting.

daenz 4y ago

Great 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 ago
iirc, 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 ago
  Fun 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 ago
    We use 80 mesh garnet.

JumpCrisscross 4y ago

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

shirleyquirk 4y ago
I 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.
nostrademons 4y ago
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/Explosive_lens https://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosion-type https://en.wikipedia.org/wiki/Nuclear_weapon_design#Implosio...

BurningFrog 4y ago

Aha! So the shape is such that all parts of the cone converge at the center, so the full energy of the explosive is focused in that thin column.

jacquesm 4y ago

The time scale on those is very interesting.