There are many effective parameters in impact mechanics. In this article, the relation between the depth of penetration and the projectile nose shape has been investigated. Projectiles were made of AISI 4340 material with flat, ogive, and hemispherical nose shapes. Semi-infinite targets made of alumina ceramic 99.5 and aluminum 7000. The projectile impact velocity in this experimental test was about 400m/s and the thickness of ceramic and aluminum were 4 and 20mm, respectively. A numerical simulation has been conducted by Abaqus software. The results of the numerical simulation show a good agreement with the empirical observations. The depth of penetration for the flat projectile and ogive projectile was highest and lowest, respectively. The ballistic limit velocity for the flat projectile and ogive projectile was lowest and highest, respectively. Projectile erosion is affected by the ceramic thickness and the shape of the projectile. The amount of this erosion for the flat projectile and ogive projectile was lowest and highest, respectively. Increasing ceramic thickness leads to more erosion in the projectile. Also, the changes of ballistic limit velocity have been determined with the changes of ceramic and backing metal thickness.
 

Efforts to reduce the ballistic effects and achieve the good results have always been important. In this article, perforated targets were used in order to reduce the penetration depth of projectile. The use of these targets in the case of high-speed projectiles reduces the number of parameters, such as penetration depth, cost of target products, and target area density. The goal of this paper was to present a new and complete analytical model for projectile penetration in ceramic/metal semi-infinite perforated targets, based on the Fellows analytical model, one of the most important models for penetration. First, the Fellows model was modified for ceramic/metal semi-infinite none-perforated targets. This modified model, while perfectly improving the results of the penetration depth at low speeds and had a better fit with experimental results at high speeds. In the new analytical model, 7 different states were considered for the projectile to impact the perforated target. In each of these states, the angle of oblique and the speed of the projectile after reaching the metal varied with respect to the ceramic thickness and the speed of the projectile's impact. Regarding the oblique impact on the metal, corrected relations were rewritten for new conditions. Finally, the depth of penetration was achieved according to the target conditions. The numerical simulation in Abaqus software was used to compare the results. The results of the new analytical model has good agreement with numerical simulation.