In such an impact, the pressure and temperature can exceed those found at the centre of the Earth, e.g. greater than 365 GPa and more than 6000 K.
The little divot on the backside of the plate is called spalling. Basically you have a thick plate of fairly brittle metal, and when it gets hit hard, the (compression) shockwave travels through the material without dissipating much. When it reaches the end of the plate, it can go no further and essentially 'bounces' back, turning into a pulling force, which pulls the material apart. If the impact had been a little stronger, that bottom part would have come loose entirely and could have ejected at lethal speeds.
Which is why the Brits developed Chobham Armor. Layered material absorbs the shock better (Ceramic tiles layered with elastic material, encased within a metal framework and bonded to a backing plate that prevents spalling. It doesn't mean that it's full-proof but it's better than a slab of metal for the reasons that you point out above.ReplyDelete
"Audentes, Fortuna, Ivat!!,"
Fortune certainly does favor the bold. Always good to leaven the bold with a healthy dollop of prudence, though, recalling the old saw about no old, bold crop-dusters!Delete
If my arithmetic is correct that is 15,214.42 mphReplyDelete