## Publica

Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten. # Hypervelocity impact of rod projectiles with L/D from 1 to 32

Hochgeschwindigkeitimpakt von Stabprojektilen mit Schlankheitsgraden von 1 bis 32

**Abstract**

Beside a short remark on the "hydrodynamic theory of rod projectiles", the paper deals with the terminal behaviour of cylindrical projectiles against semi-infinite targets. Experimental data of EMI, completed by results of some other authors, are presented. Crater parameters like depth, diameter and volume and their dependence on projectile velocity (up to 5000 m/s), projectile and target material properties as well as L/D-ratios (1-32) will be discussed. Mainly the projectile materials and tungsten sinter-alloys are considered. Target materials are mild steel and high strength steel, an Al-alloy and a tungsten sinter-alloy. The results show that the influence of material density on the crater dimensions is considerable greater than the influence of strength. The L/D-ratio destines the velocity dependence of crater depth, diameter and volume. In the case of short cylinders (L/D=1), the crater depth is nearly proportional to v sub 2/3 (v sub p = projectile velocity) in the dydrodynamic regime. The slope of the penetration curves decreases with increasing L/D and converges for rods a saturation. A consequence of this saturation is the existence of a so-called "tangent velocity", above which an optimal increase of efficiency is only realized by increasing the projectile mass and not the velocity. Furthermore, ballistic limits of real targets like single plates and symmetric double plates (meteorite bumper shield) are taken into account. The expected better performance of "segmented rods" is also discussed.