Ballistic performance of unidirectionally oriented carbon fiber reinforced composite armor with high-velocity impact

Abstract

For the last few decades, composite materials have been more popular than other conventional metal materials in the aircraft industry. Having better mechanical properties (strength, fatigue life, impact strength, corrosion resistance, etc.) and being lighter than conventional engineering materials, composites have become very important in defense industry as well. In spite of the fact that some of the composite materials such as aramid-based composites have been effectively used in body protection, they have not been so successful in heavy armored vehicles which are generally equipped with different types of add-on armor blocks for protecting against threats. These add-on armors are mostly composed of armor steels and ceramics. This study specifically aims to investigate high-velocity impact behavior of unidirectionally oriented carbon fiber reinforced/epoxy layer sandwiched with armor steel plates that are exposed to kinetic energy projectile. Carbon fibers are normally very brittle to transverse loading direction, contrarily, to its 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 for manufacturing a layer in order to replace ceramics in add-on multilayer composite armor. In order to prove this hypothesis, an experimental analysis has been carried out by performing impact tests on these manufactured add-on armor test samples. Testing was carried out in accordance with the STANAG 4569 level-4 standard. The results indicated that the multilayer carbon fiber reinforced epoxy composite–armor steel hybrid panels can provide level-4 protection with a lower areal density compared to Rolled Homogenous Armor.

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

“…The symmetric boundary condition could not be used because the projectile impact location was different for each shot in the experimental study. The projectile’s degree of freedom was defined in terms of allowing movement in the only z -direction, and the impact velocities of the projectile were defined the same as the impact velocity of the projectile on the composite armor panels in the experimental study 21 (Table 5).…”

“…In an earlier study, 21 high-velocity impact experiments of multilayer small and large composite armor panels were carried out in accordance with the STANAG 4569 level-4 standard. In the present study, primarily numerical simulations of these panels were performed to validate the numerical model of panels by experimental data, and then the verified numerical model was used to examine the high-velocity impact response of multilayer composite armor with reduced areal density.…”

“…The number of layers, the orientation of carbon fibers, and the fiber position have been selected in a manner different from the case of other composite structures that are commonly used in armoring of land vehicles vulnerable to impacts in the earlier study. 21 To realize this, a numerical model was designed by using a carbon fiber-epoxy composite structure oriented with all carbon fibers parallel to impact direction and armor steel plates to form a hybrid multilayer composite structure to investigate its response against high-velocity impact. The numerical model was later verified by the data obtained from the earlier experimental study.…”

“…The numerical model was later verified by the data obtained from the earlier experimental study. 21 Thus, the main focus of the present study was to develop the validated numerical model by using experimental data obtained and examine the effect of unidirectional carbon fiber orientation parallel oriented to impact direction on high-velocity impact (HVI) resistance of a light hybrid composite structure by numerical simulations. The numerical models were created in the ANSYS LS-DYNA program.…”

“…Numerical and experimental comparison of high-velocity impact tests 21. and LP respectively mean Small Composite Armor Panel and Large Composite Armor Panel, υ p is the projectile velocity, PP and PL respectively mean Partial Penetration and Plugging.…”