# Projectile penetration in solid

1. Jan 3, 2009

### tuoni

A simple modelling of projectile penetration in a fluid was simplee (drag), but with solids I'm having a little trouble. Would it be too crude an estimation to use the following model?

$F = \frac{E}{\delta{s}}$

F = projectile force
E = kinetic energy
s = depth in steps

$\tau = \frac{F}{A}$

τ = shear stress
F = projectile force
A = cross-sectional area of projectile

The force is calculated from kinetic energy and penetration depth in steps (e.g. 10 mm or 100 mm). As long as the shear stress (force over area) is greater than the shear strength of the solid, the projectile will penetrate the step in depth.

Should I also consider compression of the mass in front of the projectile?