ballistic protection
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Modern ballistic helmets made from textile composites offer enhanced protection with lightweight, but the discontinuity of the reinforcing materials is a potential problem affecting the helmet performance. This work uses 3D angle-interlock fabrics to provide reinforcement continuity, and evaluates 3D through-the-thickness angle-interlock (TTAI) fabrics to study the influence of fabric structural parameters on fabric mouldabilty and ballistic performance for ballistic helmet application. The mouldability was measured through experiments and modelled numerically, and the ballistic impact test was carried out to identify the optimal fabric structures for constructing ballistic helmet shells. The results show that increase in weft density of the TTAI fabrics causes decrease in the mouldability of the TTAI fabrics, and that the addition of wadding yarns into the TTAI fabrics has little influence on fabric mouldability compared to the conventional TTAI fabrics with the same weft density. However, the involvement of wadded TTAI fabrics demonstrates a 34% increase in ballistic energy absorption and 3% higher estimated ballistic limit over the conventional counterpart. Taking both mouldability and ballistic protection into account, the wadded TTAI fabric structure is an effective continuous reinforcement for ballistic helmet shells, offering required mouldability and improved ballistic performance.

Maraging steel is a low carbon steel known for its ultra high-strength after heat treatment. In combination with Additive Manufacturing (AM), the properties of maraging steel indicate potential to enable complex geometries and improved performance-to-weight ratios for ballistic protection. This study investigates the ballistic performance of AM maraging steel monolithic plates and profile panels fabricated by powder bed fusion. The mechanical properties of the maraging steel, both in the as-built state and after heat treatment, were revealed through quasi-static and dynamic tests in three different directions with respect to the build direction. Metallurgical studies were also conducted to investigate the microstructure of the material both before and after testing. The ballistic perforation resistance of the maraging steel samples was disclosed in a ballistic range by firing 7.62 mm APM2 bullets towards the different target configurations. Ballistic limit curves and velocities were obtained, demonstrating that the thickest heat-treated AM maraging steel plate has a particularly good potential for ballistic protection. The hard core of the armour piercing bullet broke in all tests and occasionally shattered during tests with heat-treated targets. However, due to the severe brittleness of the material, the targets showed significant fragmentation in some cases and most significantly for the profile panels.

Abstract SSAB Ramor 500 is a nickel-chromium-molybdenum-boron, alloy protection steel that is used in the quenched condition (hardness = 490–560 HBW) for ballistic protection. This datasheet provides information on composition, hardness, tensile properties, and bend strength. It also includes information on forming, heat treating, and joining. Filing Code: SA-875. Producer or source: SSAB AB.

The results of studies of the main characteristics of ballistic organocomposites with the use of aramid fibers of the third generation Rusar-S of various textile structures as a reinforcing filler are presented. Their physical and mechanical properties were determined, and an assessment of the splinter resistance of these materials was carried out. Use of new fibers in composite armored products enables to increase their anti-splinter resistance by 11%.

Due to its chemical and mechanical properties, polyurea gains more and more interest in military applications. In this study, polyurea and carbon nanotubes were processed as coating polymer composites for ballistic plates and/or packages, in order to increase their protection potential, meanwhile maintaining an appropriate weight and an economic accessibility. In this respect, the composite material was layered on various commercially-available materials and various thicknesses and further, the performances of the products obtained were tested in order to assess their behavior against traumas produced by shockwave, blunt, shooting and fragment.

The purpose of this study is to examine the projectile penetration resistance of the base metal and heat-affected zones of armor steel weldments. To ensure the proper quality of armor steel welded joints and associated ballistic protection, it is important to find the optimum heat input for armor steel welding. A total of two armor steel weldments made at heat inputs of 1.29 kJ/mm and 1.55 kJ/mm were tested for ballistic protection performance. The GMAW welding carried out employing a robot-controlled process. Owing to a higher ballistic limit, the heat-affected zone (HAZ) of the 1.29 kJ/mm weldment was found to be more resistant to projectile penetration than that of the 1.55 kJ/mm weldment. The ballistic performance of the weldments was determined by analyzing the microstructure of weldment heat-affected zones, the hardness gradients across the weldments and the thermal history of the welding heat inputs considered. The result showed that the ballistic resistance of heat affected zone exist as the heat input was decreased on 1.29 kJ/mm. It was found that 1.55 kJ/mm does not have ballistic resistance.

This study describes a simple, practical, inexpensive, improved, and efficient novel method for obtaining polyurea-polyurethane-multiwall carbon nanotubes (MWCNTs) nanocomposites with enhanced mechanical properties, and their experimental testing in a dynamic regime. SEM and micro-CT investigations validated the homogeneity of the nanocomposite films and uniform dispersion of the nanofiller inside the polymeric matrix. The experimental measurements (TGA, DSC, DMA, and tensile tests) revealed improved thermal and mechanical properties of these new materials. To demonstrate that these nanocomposites are suitable for ballistic protection, impact tests were performed on aluminum plates coated with the polyurea-polyurethane MWCNTs nanocomposites, using a Hopkinson bar set-up. The experimental testing in the dynamic regime of the polyurea- polyurethane-coated aluminum plates confirmed that the nanocomposite layers allow the metal plate to maintain its integrity at a maximum force value that is almost 200% higher than for the uncoated metallic specimens.

In this paper, hybrid composite plates for ballistic protection were investigated experimentally and numerically, with a target to reduce the weight of currently used body armor inserts and, at the same time, satisfy the requirements of the National Institute of Justice’s (NIJ) ballistic protection standards. The current study has three phases to improve the ballistic plate’s energy absorption capability. The first phase is devoted to studying the effect of the material types, including three different fibers: carbon fiber, date palm fiber, and Kevlar fiber. The second phase is dedicated to studying the effect of hybridization within layers. The two previous phases’ results were analyzed to optimize the material based on the hybrid composite ballistic plate’s maximum energy absorption capability. The commercial finite element software package LS-DYNA was employed for numerical modeling and simulation. The hybrid composite ballistic plate could absorb more impact energy than the non-hybrid Kevlar plate with the same area density from the numerical simulation results. This study provides lighter-weight ballistic inserts with a high protection level, making movement easier for the wearer. The numerical results were verified by comparing results of a plate made of 40 layers of Kevlar with an actual ballistic test. The results indicated that the simulation results were conservative compared to the ballistic test.