Assume that the energy transferred in the collision between the shell and the armor plate in exercise 12 affects only the shaded area of the armor plate beneath contact with the flat tip of the shell (a circle of diameter 0.010 m) and does not spread out to affect the rest of the plate. What is the energy density delivered within that shaded volume by the shell?

Imagine the idealized situation as shown in Figure A for an artillery shell striking an armor plate made of an (imaginary) metal called “armory.” Figure B is the stress–strain diagram for armory. Assume the material diagram shows armory strained to failure.

Exercise 12

Suppose the shell has a mass of 1.0 kg and is traveling at 3.0 × 10² m/s. How much TKE does it carry?

10,000 0.10 m Stress, o (GPa) 5,000 0.010 m Dia. Shell -1.0 Strain, (%) 1.0 -5,000 Armor Plate -10,000 A