Theoretical Analysis of Bulletproof Capability of Multilayer Ceramic Composites Subjected to Impact by an Armor Piercing Projectile

Inspired by the theories of Tate and Zaera, a theoretical analysis model including the erosion of the projectile, the cracking of ceramic composites, and the deformation of metal backplate was established in this study to investigate the bulletproof capability of the ceramic composites under impact by an armor piecing projectile (AP). The analysis results were verified by ballistic tests. As for the ceramic composites, the volume of the cracked ceramic conoid and the change in the compressive strength were included. Regarding the deformation of the metal backplate, the plastic deformation work, the external work, and the conservation of kinetics were considered. Based on the thickness of the target plate, failure modes were separated into the plug type and the petal type. The ordinary differential equation solver of MATLAB, ode45, was adopted to solve relevant ordinary differential equations. In this study, the powder metallurgy was used to produce the Al2O3/ZrO2 multilayered ceramic composites of three layers; each layer was 3 mm in thickness. The ceramic composites were paired with a backplate made of 6061-T6 aluminum alloy with a thickness of either 1 mm or 4 mm. The ballistic tests were executed by using 0.30″ AP projectiles to impact the specimens. The results from theoretical model and ballistic tests were compared and shown consistent in the field of residual velocity, residual bullet mass, and the failure modes of the metal backplate.

Ballistic performance of powder metal Al5Cu-B4C composite as monolithic and laminated armor

In this study, ballistic performances of x wt.-% B4C (x = 5, 10, and 20) reinforced Al5Cu matrix composite samples were investigated as a monolithic and laminated composite armor component. Composite armor plates were produced by the powder metallurgy method. The prepared powders were pressed under 400 MPa pressing pressure. Green compacts were pre-sintered at 400 °C for 30 minutes in order to blow the lubricant. Subsequently, liquid phase sintering was performed at 610 °C for 210 minutes. In ballistic tests, 7.62 mm caliber armor-piercing bullets were used as the ballistic threat. In the ballistic tests of monolithic armors, only 10 mm thick powder metal composite plates were tested. In the ballistic tests of laminated composite armors, these powdered metal plates were layered with 10 mm thick alumina ceramic plate front layers and 10 mm thick AA5083 plates. Although all of the monolithic powder metal composite armors were penetrated, they showed multi-hit capability. All of the laminated composite armors provided full ballistic protection. It was determined that with the increase in B4C reinforcement rate, the ballistic resistance also increased due to the improvement in strength, hardness, and abrasive feature.

Comparative analysis of different types of ballistic barrels used in the ammunition researches

Manufacturers offer different types of ballistic barrels made in according to various standards. The paper presents comparison of three types of ballistic barrels: pressure, velocity and accuracy made according to C.I.P. and NATO EPVAT standards. Projectile velocities in a several measuring points on the flight path and propellant gas pressures in the barrels were measured and compared. The main aim of the article is to discuss whether all types of barrels to conduct most ballistic tests are needed, or whether one, the most universal in a specific caliber is enough. Keywords: mechanical engineering, ballistics, firearm, ammunition researches, ballistic properties

PROSPECTS FOR CREATING DISCRETE-REINFORCED ARMOR COMPOSITES BY EXPLOSION WELDING

The paper presents the results of research on the creation of discrete-reinforced composite armor (DAC) by explosion welding. The advantages of new-generation composite armor and comparative data with the best analogues of domestic bullet-proof vests and armor panels are presented. Based on the results of ballistic tests, it was found that the DAC armor corresponds to the level of protection for class 5, i.e. it is not penetrated by bullets of increased hardness. It is shown that even after multiple bullet hits, the DAC armor retains its integrity and strength.

The malfunction of a double-base propellant gas generator

The paper presents results of research aimed at determining the cause leading to the malfunction of a double base gas generator. For the purposes of this work, gas generator charges and combustion chambers were intentionally damaged in order to replicate failure conditions. Damage to the inhibitor covering the gas generator and contamination in the combustion chamber, was simulated. The damaged charges and chambers were subjected to ballistic tests.

Ballistic tests of double-based propelling charges with different carbon black content

Nitrocellulose and nitroglycerin are the main components of double-base propellants comprising up to 95% of their total mass. A chemical stabiliser and a burn rate modifier are required components, added in amounts of several percent. The study analyses the effect of carbon black content, contributing less than 1% of the propellant mass, on the burning rate of differently shaped propelling charges. The experiments, carried out on high energetic, double-base propelling charges, showed that the carbon black content significantly affects the burning rate of the propelling charge in the rocket motor chamber.

Ballistic Performance of Ramie Fabric Reinforcing Graphene Oxide-Incorporated Epoxy Matrix Composite

Graphene oxide (GO) incorporation in natural fiber composites has recently defined a novel class of materials with enhanced properties for applications, including ballistic armors. In the present work, the performance of a 0.5 vol % GO-incorporated epoxy matrix composite reinforced with 30 vol % fabric made of ramie fibers was investigated by stand-alone ballistic tests against the threat of a 0.22 lead projectile. Composite characterization was also performed by Fourier-transform infrared spectroscopy, thermal analysis and X-ray diffraction. Ballistic tests disclosed an absorbed energy of 130 J, which is higher than those reported for other natural fabrics epoxy composite, 74–97 J, as well as plain Kevlar (synthetic aramid fabric), 100 J, with the same thickness. This is attributed to the improved adhesion between the ramie fabric and the composite matrix due to the GO—incorporated epoxy. The onset of thermal degradation above 300 °C indicates a relatively higher working temperature as compared to common natural fiber polymer composites. DSC peaks show a low amount of heat absorbed or release due to glass transition endothermic (113–121 °C) and volatile release exothermic (~132 °C) events. The 1030 cm−1 prominent FTIR band, associated with GO bands between epoxy chains and graphene oxide groups, suggested an effective distribution of GO throughout the composite matrix. As expected, XRD of the 30 vol % ramie fabric-reinforced GO-incorporated epoxy matrix composite confirmed the displacement of the (0 0 1) peak of GO by 8° due to intercalation of epoxy chains into the spacing between GO layers. By improving the adhesion to the ramie fabric and enhancing the thermal stability of the epoxy matrix, as well as by superior absorption energy from projectile penetration, the GO may contribute to the composite effective ballistic performance.

Natural Fiber Reinforced Composites as Bulletproof Panel Materials

The panel attached in bulletproof vests must fulfill the standard of NIJ 0101.06. It must resist the penetration of the bullet and has a back-face signature that does not exceed 44 mm by ballistic testing. This research included both numerical simulation and ballistic tests for validation using type IV ballistic bullet. This research involved composite epoxy-HGM-hemp (Boehmeria Nivea) and epoxy-HGM-sisal (Agave Sisalana) as bulletproof panel materials with their woven-thickness characteristic. The properties of materials are obtained by performing ASTM D3039 test. As a result, by varying the thickness or each amount of layer, the thinnest panel of each material that fulfills the standard of NIJ 0101.06 is obtained.

Comparative Analysis of Object Digitization Techniques Applied to the Characterization of Deformed Materials in Ballistic Tests

Several three-dimensional scanning methods have been developed and improved over the past 40 years. The peculiarities of each technique, associated with the computational advances of the period, allowed the increasing application and diffusion of the technology in several sectors, among them those related to metrology in ballistics and the testing of protective materials. The specific goal of such ballistic tests is to estimate the depth of indentation caused by projectiles. In particular, this study presents a comparative analysis between two three-dimensional optical scanning methods, taking into account the same object of interest. The comparative analysis was based on reference planes detected by Random Sample Consensus methodology in each cloud. By comparing the results of the different techniques, it was found for this case that three-dimensional reconstruction by stereo images estimated values closer to the real ones in comparison to those estimated by the structured light scanner, mainly due to the fact that, for three-dimensional reconstruction, the image acquisition was conducted statically.

Ballistic performance of sandwich panels made of wood/plastic/metal and woven glass fiber

This study investigated the ballistic properties of oriented strand board panels supported by different proportions of woven glass fiber and waste polypropylene. In the ballistic tests, galvanized metal plates of three different thicknesses (M1, M2, and M3) were used to absorb the initial velocity of the projectile. The materials forming the ballistic panel were arranged using the hand lay-up method. The waste polypropylene plates were melted on the upper and lower surfaces of the lay-up forming the panel. Production conditions were applied at 170‒175°C and 3.5‒4.0 N/mm2 for 10 min. Ballistic tests were performed on the panels according to the Level IIA category of the US National Institute of Justice standard. As a result of the ballistic test firing, the ballistic panel consisting of 1.5-mm-thick metal plate, 50 woven glass fibers, and OSB exhibited the best strength. As a result of the study, it was determined that the mechanical properties of the material that absorbed the initial velocity of the projectile were effective in the ballistic performance of the panels.