PurposeThis study aims to elucidate the penetration mechanism of tungsten alloy long-rod armor-piercing projectiles impacting ceramic-rubber composite armor under oblique angles. The objective is to understand how varying attack angles influence projectile failure behavior, energy dissipation within armor materials, and overall protection performance. Additionally, the study seeks to explore the potential of structural optimization to enhance armor efficiency, either by reducing weight or improving resistance, thereby providing design guidance for advanced composite armor systems subjected to angled threats.Design/methodology/approachA finite element model was developed in LS-DYNA to simulate the oblique impact of tungsten alloy long-rod projectiles on ceramic-rubber composite armor. The study analyzed projectile velocity evolution, failure modes, and stress distribution under different impact angles. Mass erosion, ceramic fragmentation, and energy dissipation mechanisms were examined in detail. Furthermore, a multi-objective optimization approach was applied to minimize areal density or maximize residual velocity without compromising ballistic performance. The combined numerical simulation and optimization framework provides insights into armor response and structural improvements under asymmetric loading conditions.FindingsMulti-objective optimization demonstrates that through angle-dependent structural adjustments, either a 4.89% areal density reduction or 14.77% residual velocity increase can be achieved without compromising ballistic protection.Originality/valueThis study reveals the coupled influence of oblique impact angles on the failure mechanisms of long-rod penetrators and the energy absorption characteristics of ceramic-rubber composite armor. It provides new insights into asymmetric stress-induced shear localization and projectile erosion under high obliquity. The integration of viscoelastic effects, ceramic fragmentation, and frictional interactions enhances understanding of composite armor performance. Moreover, the application of multi-objective structural optimization demonstrates that significant weight reduction or improved resistance can be achieved without compromising protection, offering valuable guidance for the lightweight design and efficiency enhancement of advanced armor systems.

This study investigates the ballistic performance of epoxy matrix composites reinforced with raffia fabric, aiming to evaluate their potential as the second layer in multilayered armor systems (MAS), replacing conventional synthetic aramid (Kevlar™) laminates. Composite plates with different volumetric fractions of raffia fabric (10, 20, and 30%) were manufactured and integrated with a ceramic front layer (Al2O3/Nb2O5) in MAS structures, which were then subjected to ballistic impact tests using high-energy 7.62 mm caliber ammunition. The backface signature (indentation depth) measured in ballistic clay, used as a human body simulant, showed that only the 10% raffia-reinforced composite (ER10) met the National Institute of Justice (NIJ 0101.06) safety threshold of 44 mm. Higher raffia contents (20% and 30%) led to increased indentation, compromising ballistic integrity. Scanning electron microscopy (SEM) of the fractured surfaces revealed typical energy dissipation mechanisms, such as fiber rupture, fiber pull-out, and interfacial delamination. The results indicate that raffia fabric composites with 10% fiber content can serve as a cost-effective and sustainable alternative to Kevlar™ in personal armor applications, while maintaining compliance with ballistic protection standards.

There has been a reported increase in combat-related head, face, and neck (HFN) injuries among service personnel wearing combat body armor (CBA) that have deployed to Iraq and Afghanistan. Modern ceramic plate CBA has decreased the incidence of fatal-penetrating injuries to the torso but offers no protection to the limbs and face which remain exposed to gunshot wounds and fragments from explosive devices. The aim of this review was to systematically summarize the literature reporting on HFN injuries sustained by combat personnel wearing CBA and to highlight recommendations for increased protection to the facial region. Three major contributing factors were identified with this proportional increase in HFN injuries, namely the increased survivability of soldiers because of CBA, fragments injuries from explosive devices, and the lack of protection to the face and limbs. There appears to be no evidence to suggest that by virtue of wearing CBA the likelihood of sustaining an HFN injury increases as such, but a higher incidence of fragment injuries to the HFN region may be due to the more common use of improvised explosive devicess and other explosive devices. Further development of lightweight protection for the face is needed.

Ceramic armor with improved ballistic performance, lower weight, and, in specific cases, complex geometry is of high importance for the armor integrators and users. The combination of a high level of consolidation and the tailored heterogeneous structures of these ceramics may be important for reducing fracturing and delaying crack propagation under high-velocity ballistic impacts, therefore improving their ballistic performance. This can be attained by a beneficial combination of advanced ceramic compositions and processing, e.g., through an additive manufacturing (AM) approach. For example, the functionally graded (FG) monolithic ceramic armor obtained by AM can encompass a few layers, where the front layer has higher hardness, and the layer(s) behind may have higher fracture toughness. The ingredients reinforcing the ceramic structure may also be involved. The graded architecture should provide the internal stress reduction under high-velocity mechanical (ballistic) impacts. The reaction bonding that provides consolidation of the AM-based ceramic armor may also be involved. The considered principles of the FG materials' formation may be employed for personnel, vehicular, and structural armor systems. The possibility of formation of ceramic armor with graded structures and compositions using AM was reviewed and analyzed for the first time. The proposed armor designs, which can be obtained by AM, may provide enhanced ballistic performance combined with lower weight.

<div class="htmlview paragraph">Advanced lightweight ceramic/composite armor systems have been investigated for the defeat of ball and armor piercing projectiles. Several material systems have been identified that will provide weight reductions of approximately 33% - 45%. The materials investigated for this effort include Boron Carbide (B<sub>4</sub>C) and Silicon Carbide (SiC) ceramics combined with high strength fiber reinforced plastic backing materials such as Kevlar 29, KM2, Spectra 900, 1000 and SpectraShield. An extensive database is also being complied for other less expensive alternative armor materials against an array of small arms threats. The materials and systems developed are applicable for combat vehicles, aircraft, executive vehicles and personnel protection.</div>