An approximate contact pressure for normal penetration of rigid ogive projectiles into metal targets

An approximate analytical expression for the contact pressure applied by a metal target to a rigid ogive projectile is determined by generalizing the analytical expressions developed previously for penetration of a rigid ovoid of Rankine into an incompressible elastic-perfectly-plastic target. Two empirical shape factors are introduced and determined which model the geometric dependences of the terms in the contact pressure due to the target's yield strength and inertia. Analytical expressions are determined for the resistance to penetration which depend on the ogive's shape and which determine the critical penetration velocity for the onset of separation of the target material from the projectile's nose. Also, a procedure for determining the effective yield strength of a general target material is presented. Results of numerical simulations for different ogives and different target materials are used to validate the proposed analytical equations. Some results are compared with experimental data.