Quote of the day—Wikipedia, Shaped charge

Most of the jet formed moves at hypersonic speed. The tip moves at 7 to 14 km/s, the jet tail at a lower velocity (1 to 3 km/s), and the slug at a still lower velocity (less than 1 km/s). The exact velocities are dependent on the charge’s configuration and confinement, explosive type, materials used, and the explosive-initiation mode. At typical velocities, the penetration process generates such enormous pressures that it may be considered hydrodynamic; to a good approximation, the jet and armor may be treated as incompressible fluids, with their material strengths ignored.

Wikipedia, Shaped charge
Emphasis added.
Found while Wikiwandering from a link at Roberta’s.
[“… may be treated as incompressible fluids, with their material strengths ignored”! That statement makes me light-headed and weak at the knees. The “7 to 14 km/s” doesn’t hurt either.

7 km/s is about 23,000 feet per second. Your .220 Swift is considered a very zippy cartridge but it only gives you about 4,100 feet per second at the muzzle. Hence a shaped charge gives you velocities 5 to 10 times that of a .220 Swift at the muzzle. This is considered high-hypersonic to re-entry speeds.

I have books on computer simulation of shaped charges. I really need to write the software then do some field testing. Supposedly it is pretty easy to punch through three feet of reinforced concrete. I have some large rocks out in the middle of some fields I’d like to experiment with.—Joe]


8 thoughts on “Quote of the day—Wikipedia, Shaped charge

  1. MadRocketScientist,

    How do I obtain LS-DYNA? I poked around some but didn’t see either sales information or free download.

  2. Copper makes really good EFP’s. Steel not so much, there seems to be of some sort ideal malleability and density that makes copper a good EFP.

    Any angle up to 45 degrees will work as well for the shaped charge. For anti tank missiles we use a very shallow angle, probably 20 degrees (didn’t check last time I had access to a mockup warhead).

  3. The variations in cone angles are to do with whether/how much the warhead is rotating at time of detonation. Non-rotating, fin-stabilized, projectiles are used in preference by designers because rotation disrupts the forming of the slug. The shallower cones are used in rotating projectiles.

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