Armor Systems Research Articles

An Attempt to Predict Transparent Armor Ballistic Performance through Quasi-Static Punch Shear Test

Abstract Background Transparent armor systems are traditionally designed following a trial-and-error approach, which involves high development costs associated with ballistic testing. This research article presents a novel methodology, termed quasi-static multi-punch shear testing, within the domain of transparent armor systems. Objective The primary aim is to establish a correlation between multi-hit ballistic tests at Level III-A according to the NIJ 0108.01 standard, achieved through an adaptation of the single-shot ballistic limit methodology, and the quasi-static multi-punch shear testing. The objective is to utilize a simple experimental methodology that provides insights into the multi-hit ballistic behavior of transparent armors. Methods Parameters such as absorbed energy and observed damage mechanisms were utilized to assess the potential relationship between these tests. Transparent armor samples that underwent testing using the quasi-static multi-punch shear test were subsequently cross-sectioned using a water jet cutting machine to facilitate visualization of material damage. In addition, drawing on insights from quasi-static multi-punch shear testing results, the K-means clustering algorithm was employed to predict the likelihood of a specific transparent armor system passing a multi-hit ballistic test. Results Various damage mechanisms were observed as a function of the punch displacement, and correlations were made with the load–displacement curves. Furthermore, the implementation of the K-means clustering algorithm successfully classified transparent armor into two groups: those that passed the ballistic test and those that did not. Conclusions This research significantly advances understanding of transparent armor system behavior under multi-hit conditions and offers a promising predictive tool for evaluating their performance through straightforward and cost-effective experimentation.

Additive manufacturing process in the production of ceramics used in armor systems: a review

The evolution of materials and their transformation processes into products has paralleled the development of humans. While the conventional steel transformation process is well understood, processes such as additive manufacturing have been studied for polymers, metals, and ceramics. Regarding ceramics, it is observed that most products stem from sintering processes, while additive manufacturing is still limited by operational constraints derived from the properties of this material class. Thus, it is essential to understand, within additive manufacturing processes for ceramics, which ones are possible to produce the green body or even the final product. This work focuses on presenting the technologies available in the market, showing in a comparative manner the main characteristics, applications, and limitations focus on ballistic applications.

Bio-inspired helicoidal hemp/basalt/polyurethane rubber bio-composites: Experimental, numerical and analytical ballistic impact study with residual velocity prediction using artificial neural network

Recent body armour trends emphasize mobility, flexibility, and cost reduction while maintaining ballistic effectiveness through the use of natural fiber composite. This study evaluates the ballistic impact performance of soft and hard armor using experimental, analytical, numerical, and machine learning methods. We developed a soft armor bio-composite using monolithic, hybrid, and helicoidal structured Hemp (H)/Basalt (B)/Polyurethane (PU) rubber and tested its V50 ballistic limit according to Millitary-Standred-662 F. For hard armour, a multi-layer armor system (MAS) consisting of Al2O3/SiC ceramic, intermediate soft armour bio-composites, and an Aluminum (Al)-5052 plate backing was tested with armour-piercing bullets as per National Institute of Justice (NIJ)-0101.06 standards (Level IV). Soft armor performance was evaluated using macro-homogeneous finite element (FE), the Ipson-Retch analytical, and an Artificial Neural Network (ANN) regression model. Results showed minimal discrepancies from experimental data, with differences of 13.33 %, 12.08 %, and 8.08 % in V50 ballistic limit. The mechanical and thermal behaviors of bio-composites were assessed using un-notched Charpy, FTIR, and TGA methods. Helicoidal laminates improved Charpy toughness by 9.44 %, 19.30 %, and 40.28 % compared to hybrid and monolithic ([H]15 and [H]10) laminates, and exhibited lower weight reduction at high degradation temperature of 395.76 ℃. Helicoidal laminates increased V50 ballistic performance by 155.80 %, 76.22 %, and 16.61 % compared to [H]10, [H]15, and hybrid laminates, respectively. Due to spiral load distribution reduces stress concentration and enhanced the damage resistance of the laminate. Stand-alone soft armor demonstrates crater formation and radial cracks (petaling) due to fiber wedging and the shearing effect of a bullet. In conclusion, MAS revels a maximum back face deformation (BFD) of 18.06 mm. Al2O3/Helicoidal/Al-plate MAS reduced weight and cost by 69.21 %, and 233.72 % compared to Kevlar™-based MAS, promoting sustainable, lightweight, economical designs. Due to its higher fracture toughness and lower density, SiC ceramic in MAS provides lower trauma and further reduced weight compared to Al2O3 ceramic.

Three-Dimensional Printing of Cuttlebone-Inspired Porous Ceramic Materials.

Lightweight and strong ceramic materials are attractive for tissue engineering, aerospace, armor systems, and many high-temperature applications. Cuttlebone, primarily composed of bioceramics, features a unique S-shaped wall structure that contributes significantly to its remarkable mechanical properties. Here, we explore the hierarchical structure and components of the cuttlebone and reveal the high ceramic content in S-shaped walls. Inspired by the design of the cuttlebone, we developed a high ceramic loading slurry for three-dimensional printing cuttlebone-like structures. As shown in the compression test, the fabricated bioinspired ceramics exhibit excellent mechanical properties and can withstand 1.07 million times their own weight, outperforming traditional ceramic foams. The specific strength and modulus are 59.5 and 785.6 MPa/(g cm-3), 9 and 36 times that of the natural cuttlebone. The failure mechanisms are also systematically studied on the basis of tuning the structural parameters. These findings provide effective solutions and inspiration in fabricating high-performance ceramic structural materials.

Virtual fit assessment of U.S. army body armor using NASA spacesuit techniques

Fit and accommodation are critical design goals for a body armor system to maximize Soldiers’ protection, comfort, mobility, and performance. The aim of this study is to assess fit and accommodation of body armor plates for the US Army. A virtual fit assessment technique, developed, validated, and deployed by NASA for spacesuit design, was adopted for this work. Specifically, 3D manikins of the Soldier population were overlaid virtually with geometrically similar surrogates of the armor plates. Trained subject matter experts with the US Army and NASA manually assessed the fit of the armor plates to manikins using a computer visualization tool and selected the appropriate plate size and position. A prediction model was built from the assessment data to predict the plate size from an arbitrary body shape and the resultant patterns of body-to-plate contact were quantified. The outcome indicated a unique trend of the plate sizes covarying with anthropometry. More pronouncedly, when the overlap between the body tissue and armor plate was quantified, female Soldiers are likely to experience a 25 times larger body-to-plate contact volume and 6.5 times larger contact depth than males on average, due to sex-based anthropometric differences. Overall, the prediction model and contact patterns provided key metrics for virtual body armor fit assessments, of which the locations, patterns, and magnitudes can help to improve sizing and fit of body armor systems, as previously demonstrated for NASA spacesuit design.

A facile method for the estimation of ceramic performance in light armor systems

AbstractBallistic armor material development has been historically constrained by the limitations of existing predictive models. Traditional approaches, primarily reliant on finite element models, are not only computationally intensive but also often fall short in accurately predicting the ballistic performance of ceramics, particularly with novel materials. This challenge is exacerbated by the lack of clear correlations between a ceramic material's mechanical properties and its ballistic efficacy in existing equations. In this context, we have developed a novel empirical equation that represents a significant shift from conventional methods. This facile formula provides a more cohesive and predictive way to estimate ballistic performance from material mechanical properties, accurately defines performance relations between different material types, and addresses the gaps that have hindered previous methodologies. This new ballistic efficacy equation conclusively answers the old question as to which mechanical properties correlate with performance in light armor systems and opens avenues for the rapid development and optimization of more effective ceramic armor materials.

Predicting projectile residual velocities using an advanced artificial neural network model

In this research, we delve into the fascinating dynamics of projectiles and their interactions with materials, with a keen focus on residual velocity — the speed a projectile retains after striking a target. This parameter is pivotal, especially when considering the design of protective barriers in various environments. Traditional methods of gauging residual velocity have been cumbersome, resource-intensive, and occasionally inconsistent. To address these challenges, we introduce an innovative approach using an Artificial Neural Network (ANN) model through MATLAB R2021a. This computerized tool, trained on a rich dataset from prior research, can predict residual velocities by considering multiple factors, including the initial speed of the projectile, its material and shape, and the thickness of the target. This paper meticulously details the development, training, and validation of the ANN model, highlighting its superior accuracy when compared to traditional methods like the Recht-Ipson model. The developed ANN model demonstrated remarkable performance compared to the Recht-Ipson model. During training, it exhibited a Mean Absolute Percentage Error (MAPE) of 0.0259 and a Root Mean Squared Error (RMSE) of 1.5993. For validation, MAPE was 0.0295, and RMSE was 2.2056. In contrast, the Recht-Ipson model displayed higher errors, with MAPE and RMSE values of 0.2349 and 14.1791, respectively. Furthermore, we discuss the potential of the ANN model in predicting not just residual velocities but also absorbed energy, showcasing its versatility. The practical implications of our findings are vast. From designing safer infrastructures in urban settings to enhancing armour systems in military applications, the ANN model's predictions can be a cornerstone for innovation.

Numerical Modeling on Ballistic Impact Analysis of the Segmented Sandwich Composite Armor System

This research delves into the design, modeling, and finite element impact analysis of the segmented sandwich composite armor system subjected to impact loading, considering different parameters such as materials to be used, armor height, and armor design configuration. Initial studies were performed to select the ideal model that will provide the best impact resistance at the least weight and with minimal fabrication requirements. Material type, thickness, and overall model configuration were defined during the initial model development period. Once the final design was defined, finite element analysis was performed using 2017 ABAQUS software to observe the performance of the model and to validate the efficiency of the chosen armor. Based on the results from the material selection and thickness validation, the optimal design with the best impact resistance was noted as 1.2 mm thick rectangular segmented silicon carbide tiles, serving as the top layer that covers the three-level gradient core composed of a titanium metal honeycomb frame filled with silicon carbide inserts, and finally a 2 mm thick glass epoxy composite layer made from four laminas in a 0/45/90/-45-degree configuration serving as the last layer of the armor.

Ballistic performance evaluation of 3-dimensional orthogonal composite soft armor systems

Ballistic performance evaluation of 3-dimensional orthogonal composite soft armor systems

Design of an add-on ceramic composite armour against 14.5 × 114 mm API/B32 projectile for the armoured vehicles and investigation of the ballistic performance of the armour

Abstract A ceramic/composite add-on armour system with innovative ceramic geometry (cylindrical) against 14.5 × 114 mm API/B32 projectile was developed and ballistic performance of the armour was investigated both experimentally and numerically. Numerical analysis was used to calculate exit velocities of the projectile after passing through the ceramic/composite layer (before penetrating the Armox 500T which simulates hull structure of an armoured vehicle) and also contributed to the selection of optimum ceramic thickness. The calculated projectile velocity-time curves (from numerical analysis) for three different ceramic thicknesses are given comparatively in the study. The curve characteristics are the same for three different analyses. The duration of the total absorption of the projectile energy is about 0.2 microseconds (ms). There were differences in the transmission of the stress wave and the delamination in the Ultra-High-Molecular-Weight Polyethylene (UHMWPE) layers differed as ceramic thickness increases. The separation between the layers varied with the change in projectile energy. As a result of the ballistic test, the armour prevented 14.5 × 114 mm API/B32 ammunition with desired damage mechanisms. In the x-ray image taken after the shootings, it was seen that the ceramic damage was local which enhanced multi-hit resistance capability and the geometry of the cylindrical alumina played an important role in the localization of the ceramic zone damage during the projectile penetration process. Due to this cylindrical ceramic geometry, the projectile moving on after the moment of impact constantly encounters a curved and new surface, and thus it is deflected and exposed to more wear. The areal density of the armour was also reduced by using the UHMWPE (which is one of the composite material whose fibres have the lowest density and good mechanical properties) composite plate as the backing plate.

A Numerical Study on the Ballistic Trauma of B4C ceramic backed UHMWPE Composite Armor System

A Numerical Study on the Ballistic Trauma of B4C ceramic backed UHMWPE Composite Armor System

Ballistic performance of monolithic rubber-ceramic composite armor

This work presents the research results regarding the ballistic response characteristics of monolithic ceramic armors. Two different configurations of armors are considered for investigation, aiming at identifying ways to increase the ballistic performance of Small Arms Protective Insert (SAPI). The first configuration consists of a monolithic ceramic tile (Al2O3) with a backing plate made of high-performance Kevlar-29 fiber reinforced composite; the second one has the same design as the first, but the monolithic ceramic tile is covered by a thin rubber layer. The impact behavior of the ceramic composite armors is analyzed numerically, using the finite element method. Some characteristic features, including the ballistic performance and the fracture conoid angle (for the ceramic tile) are discussed. The numerical models developed for the two armor configurations are validated by ballistic tests, where the projectile impact on the armors and the mechanical integrity of the armor systems after impact are observed. The results from simulations and experiments show that the Al2O3/Kevlar 29 composite armor is able to capture a 7.62 mm bullet with a striking velocity of 690 m/s and the rubber-ceramic composite armor is able to capture 5.56 × 45 mm bullet M855 (with an armor piercing tip) with an impact velocity of 894 m/s. It has been found that, when a rubber layer is placed on the front face of a ceramic composite armor, better ballistic performance is achieved. The experiments show that, when a rubber material is impacted by a projectile, its behavior at high velocities and high strain rates changes from elastic to brittle.

Comparison of biophysical characteristics and predicted thermophysiological responses of three prototype body armor systems versus baseline U.S. Army body armor systems <br>

Comparison of biophysical characteristics and predicted thermophysiological responses of three prototype body armor systems versus baseline U.S. Army body armor systems <br>

Experimental investigation on the ballistic performance of B4C/Aramid/UHMWPE composite armors against API projectile under different temperatures

In the design of lightweight composite armor, it is crucial to consider the challenging conditions of extreme environments encountered during service. This study proposes to investigate the effect of temperature on the ballistic performance of a B4C/aramid III/UHMWPE composite armor system against 12.7 mm armor-piercing incendiary (API) projectiles with an impact velocity of ∼500 m/s. A series of ballistic experiments were conducted under low temperature (-40 ℃), high temperature (+70 ℃), and room temperature (+20 ℃) respectively considering two shooting distances of 100 m (long-range shooting) and 30 m (close-range shooting). The structural failure modes and associated mechanisms were identified and analyzed in detail from both macroscopic and microscopic scales. The experimental results indicate that the designed composite armor is believed to perform better than the existing design schemes in resisting the 12.7 mm half-speed API projectile on the basis of similar or less areal density. The ballistic performance of the composite armor system is significantly enhanced at low temperatures and weakened at high temperatures in terms of structural damage levels and backplate bulge deformation. The decrease in shooting distance transformed the panel failure mode essentially from non-penetration to penetration under room and high temperatures, whereas the specimens under low temperatures could prevent penetration. Both the ceramic and composite laminate materials are affected by temperature and show different microscopic damage modes, indicating the damage mechanism changes at the microscopic level. These findings provide valuable insight into the design of lightweight composite armor systems to adapt to extreme service environments.

Experimental Investigation of Ballistic Performance of Free Particle Armor Systems

Recent armor studies generally rely on improving the single-shot capabilities of ceramic armors. In multi-shot studies, ballistics tests assume that there is a certain distribution, so these successive shots were not made from exact same point. With these shots, thus, the armor completely loses its effectiveness. In this study, the ballistic performance of damaged and undamaged free particle armor system in multiple hits from exact same and different points was experimentally investigated. The new armor system, consisting Al2O3 free ceramic balls, tested with 9 mm FMJ and 7.62 mm API ammunition. This armor system prevented perforation in multi-hits from the same point, and the depth of depression in ballistic clay was 9.42 mm and bullet deviation in trajectory was 27 mm. In the shots with dispersion, depression depth was limited to 3.52 mm and deviation increased with each shot. As a result, it has been found that the free particle armor system performs more ballistic efficiency than conventional armors even in the most challenging conditions. The ceramic balls, being more irregularly and densely spaced with each shot, increase the likelihood of the bullet hitting at larger angles and increase ricochet in direct proportion.

Determination of the Worst Case for the Ballistic Test of the Soft Armour System Using the 9mm FMJ Bullets Differing in the Structure

Abstract Ballistic tests require significant rigor and the development of a worst case model during the research processes. The purpose of this study was to evaluate the effect of bullet type (manufacturer) on V50 and Behind Armor Blunt Trauma (BABT) results for two ballistic applications: p-aramid and UHMWPE fibre. The results confirmed the thesis that the source of the bullets implies the test results obtained in terms of the number of penetrated layers in the ballistic system, backface signature deformation profiles (p-BFS) and the level of residual energy transferred to the user of the personal protection.

Investigation of the Performance of a V-shaped Inner Plate Array Armor System Against 7.62 mm Caliber Bullets

Investigation of the Performance of a V-shaped Inner Plate Array Armor System Against 7.62 mm Caliber Bullets

Study on the protective performance of high-performance multi-scale (SiCh-p+B4Cp)/5083Al ceramic array armor with excellent ballistic properties

Ceramic array armor suffers from insufficient constrained capability of ceramic units in the embedded armor structure, leading to weak interfacial bonding at ceramic unit connections, significantly reducing the overall ballistic performance. In this study, centimeter-sized SiC hexagonal prisms and micrometer-sized B4C powders were used as reinforcing materials. A high-strength, high-toughness, and multiscale array (SiCh-p + B4Cp)/5083Al armor with strong interfacial bonding was prepared using pressure infiltration technique. The (SiCh-p + B4Cp)/5083Al armor was combined with ultra-high molecular weight polyethylene and 6252 armor steel to form an integrated armor system. To investigate the effect of constrained material on its ballistic performance, the array structures with epoxy and 5083Al as constrained material were prepared for comparison. Ballistic performance tests were conducted using 12.7 mm Armor-Piercing Incendiary (API). The damage mechanisms of the armor structure were studied through finite element simulation and a combination of macroscopic and microscopic analyses. The results demonstrate excellent overall ballistic performance of the (SiCh-p + B4Cp)/5083Al armor system. The high-strength and high-toughness 55 vol%B4Cp/5083Al composite material exhibits strong interfacial bonding with SiCh-p, providing robust support to the SiCh-p. The armor back deformation was reduced by 50 %, and the ceramic layer dissipated more than 70 % of projectile kinetic energy, The materials prepared in this study exhibit significant potential in ballistic performance.

Nanocoatings for ballistic applications: A review

Abstract The manufacturing of ballistic impact-resistant (BIR) body armours has evolved over the years with the aim of reducing their weight and enhancing their energy-absorbing capacity upon ballistic impacts. The incorporation of nanoparticles into advanced BIR body armour systems is considered one of the promising techniques. The methods employed in incorporating various nanoparticles in the manufacturing of textile-based body armour systems face a research gap in the optimisation of the associated parameters. This article discusses the mechanism involved in the energy absorption of composites and nanocomposites upon ballistic impact. The current review article highlights the chemical, physical, and mechanical properties of various nanoparticles incorporated into BIR body armour systems. BIR nanocomposites consisting of carbon nanotubes, graphene nanoplatelets, nano-silica, nanoclays, nano-alumina, etc., have been discussed herein. In addition, the significance of various techniques for the dispersion of these nanoparticles was also highlighted. Various methods, such as sol–gel, PVD, CVD, thermal spray, and electroless methods for coating the nanoparticles on the surface of the fibre/fabric were also discussed.

Ballistic Behavior of Epoxy Composites Reinforced with Amazon Titica Vine Fibers (Heteropsis flexuosa) in Multilayered Armor System and as Stand-Alone Target.

Seeking to improve personal armor equipment by providing mobility and resistance to penetration, this research aimed to explore the potential of sustainable materials in order to assess their ability in ballistic applications. Titica vine fibers (TVFs) extracted from aerial roots of Heteropsis flexuosa from the Amazon region were incorporated at 10, 20, 30, and 40 vol% into an epoxy matrix for applications in ballistic multilayered armor systems (MASs) and stand-alone tests for personal protection against high-velocity 7.62 mm ammunition. The back-face signature (BFS) depth measured for composites with 20 and 40 vol% TVFs used as an intermediate layer in MASs was 25.6 and 32.5 mm, respectively, and below the maximum limit of 44 mm set by the international standard. Fracture mechanisms found by scanning electron microscopy (SEM) attested the relevance of increasing the fiber content for applications in MASs. The results of stand-alone tests showed that the control (0 vol%) and samples with 20 vol% TVFs absorbed the highest impact energy (Eabs) (212-176 J), and consequently displayed limit velocity (VL) values (213-194 m/s), when compared with 40 vol% fiber composites. However, the macroscopic evaluation found that, referring to the control samples, the plain epoxy shattered completely. In addition, for 10 and 20 vol% TVFs, the composites were fragmented or exhibited delamination fractures, which compromised their physical integrity. On the other hand, composites with 30 and 40 vol% TVFs, whose Eabs and VL varied between 166-130 J and 189-167 m/s, respectively, showed the best physical stability. The SEM images indicated that for composites with 10 and 20 vol% TVFs, the fracture mode was predominantly brittle due to the greater participation of the epoxy resin and the discrete action of the fibers, while for composites with 30 and 40 vol% TVFs, there was activation of more complex mechanisms such as pullout, shearing, and fiber rupture. These results indicate that the TVF composite has great potential for use in bulletproof vests.