NUMERICAL ANALYSIS OF CERAMIC-STEEL-COMPOSITE SHIELD SUBJECTED TO BALLISTIC IMPACT OF THE FRAGMENT

The issue of missile impact resistance is discussed in detail in many articles and standard papers dealing with body armour. The experience from many armed conflicts, however, may be proof that the real risks are related to a greater degree to fragments than those of bullets. It can be shown that the more often the object is destroyed as a result high-velocity impact of fragments. The paper describes the results of numerical simulations of 22 calibre bullet shrapnel piercing multilayer ballistic shield. The shield was made of ceramics, steel and composite materials. The shape of the fragment is based on the American the defence standard MIL-DTL-46593B. The fragment tested is made through the process of cold rolling steel 4337H or 4340H characterized by hardness of about 30 units on the Rockwell scale. The mass of the fragment is 17 grains (1.14 g). The ballistic shield, that was hit by fragmentation, was a rectangular plate made of a Kevlar composite and, in another variant, an epoxy composite. The test was conducted in accordance with the terms of ballistic fragmentation resistance test V50 contained in standard MIL-STD-662F. In undertaking the simulation was used the Finite Element Method (FEM) which is implemented in LS-Dyna programme. The numerical calculations were performed in the explicit option on a multiprocessor computational cluster. The necessary information to build a model like materials ’ properties is taken from extensive literature