A numerical model for analysis of layer thicknesses on ballistic resistance of a multilayer armor

The interest in composite materials, which are lighter and have better mechanical properties (strength, fatigue resistance, corrosion resistance, etc.) than traditional engineering materials, is increasing day by day. In particular, their responses to low or high-velocity impact loads have been among the important research topics of recent years. In this study, unlike the traditional ceramic-based composite armor structures used in the defense industry, the effect of total carbon fibers specifically parallel oriented into impact direction on penetration resistance has been investigated, and penetration resistance of a multilayer hybrid composite armor which is composed of carbon fiber composite blocks sandwiched by two armor steel plates exposed to high-velocity impact has been analyzed numerically. Carbon fibers are normally very brittle to the transverse loading direction, contrarily, to their axial tension or compression direction. This is the reason why it is claimed that this high compression strength property of carbon fibers could be used as a layer in order to replace ceramics in add-on multilayer composite armor. The numerical model created in the ANSYS LS-DYNA program was verified by using the experimental data obtained in an earlier study. The verified numerical model was used to analyze high-velocity impact simulations of multilayer hybrid composite armor for different thicknesses of armor steel to reduce the areal density. By these simulations, minimum areal density compared to Rolled Homogeneous Armor steel for equivalent protection was finally achieved, and thus the hypothesis saying that carbon fibers parallel oriented to impact direction can give high penetration resistance was proved by showing that developed multilayer carbon fiber reinforced epoxy composite–armor steel hybrid panels have indicated a better protection level than STANAG 4569 Level-4 with a lower areal density.