Small Arms Projectiles Research Articles

Performance of thin blast-loaded steel plates after ballistic impact from small-arms projectiles

It is known from real blast-load events that the combined effect of fragment impact and blast loading is more severe than the effect of the blast loading alone. The present study investigates this effect by comparing the blast response of thin steel plates pre-damaged by either ballistic impacts or idealized pre-cut circular holes under similar blast loading conditions. The ballistic impacts were performed with a rifle, firing 7.62 mm APM2 projectiles, and the subsequent blast loading was applied in a shock tube facility. During the blast tests, pressure measurements and two high-speed cameras were used to record the dynamic response of the target plates and allowed for a reliable experimental procedure. To investigate the strength-ductility trade-off dilemma of the material during extreme loading, three different steels with different levels of strength and ductility were used in the tests. Numerical simulations were conducted in an attempt to obtain more insight into the fracture characteristics of the plates.For similar loading conditions and material, the target plates exposed to ballistic impact showed a reduced resistance to fracture during blast loading compared with target plates containing pre-formed circular holes. As for the effect of material strength and ductility, the global deformation decreased, while the localization of plasticity increased, with an increased material strength. The fracture resistance was also observed to decrease with increased material strength. The numerical models were able to capture the main trends observed in the physical tests, i.e., a decrease in fracture resistance with initial ballistic impact, and a reduction in fracture resistance with increased material strength. The numerically predicted crack paths also showed a strong dependence upon the initial cracks caused by the petals from the ballistic impacts.

Normal and Oblique Impact on Polyurea-Coated ASTM1045 Steel Plates by Small-Arms Projectiles

Small-caliber steel core projectiles fired by light weapons pose a great threat to metal structures. Coating with polyurea (PU) is a potential option to improve the anti-penetration performance of metal structures. In this work, we carried out numerical simulations to clarify the dynamic characteristics of PU-coated ASTM1045 steel plates subjected to oblique penetration by 5.8-mm small-caliber steel core projectiles. The failure modes, dynamic response process, energy absorption characteristics, and comprehensive protection effects of target plates with different coating positions and thicknesses during the penetration process were compared and analyzed. The result showed that coating with a certain thickness of PU could enhance the protection ability of the steel plate against the oblique penetration of projectiles. In contrast to the results obtained from experiments in which the projectile penetrated the composite plate normally, when the PU coated both sides, the effect of improving the oblique penetration resistance of the steel plate was the best. The effect was lowest with a PU layer only on the back face. This study provides a reference for strengthening the bulletproof performance of various systems, including steel structures, weapons, and vehicles.

Effects of the impact of 7.62 mm small-arms projectiles on various building materials

The presented study deals with the experimental assessment of the effects (i.e. penetration depths) of 7.62 mm × 39 and 7.62 mm × 54 R multipurpose projectiles on various structural and shielding/cover materials. The materials selected for testing were hardwood, softwood, brick and sand. The primary focus of the testing was the effect of projectiles on samples during perpendicular impact at different impact velocities and therefore various impact energies. The secondary aim was to determine and observe projectile properties after target perforation. The observed parameters include the residual energy/velocity and structural properties of the projectiles (e.g. fragmentation).

Lead isotope ratios for bullets, forensic evaluation in a Bayesian paradigm

Forensic science is a discipline concerned with collection, examination and evaluation of physical evidence related to criminal cases. The results from the activities of the forensic scientist may ultimately be presented to the court in such a way that the triers of fact understand the implications of the data. Forensic science has been, and still is, driven by development of new technology, and in the last two decades evaluation of evidence based on logical reasoning and Bayesian statistic has reached some level of general acceptance within the forensic community.Tracing of lead fragments of unknown origin to a given source of ammunition is a task that might be of interest for the Court. Use of data from lead isotope ratios analysis interpreted within a Bayesian framework has shown to be suitable method to guide the Court to draw their conclusion for such task.In this work we have used isotopic composition of lead from small arms projectiles (cal. .22) and developed an approach based on Bayesian statistics and likelihood ratio calculation. The likelihood ratio is a single quantity that provides a measure of the value of evidence that can be used in the deliberation of the court.

RADAR IDENTIFICATION OF HOSTILE FIRE BY MEANS OF THE ELECTROMAGNETIC COMPLEX NATURAL RESONANCES OF PROJECTILES

The authors discuss and demonstrate the feasibility of using ultra wide band microwave radar to detect and identify small arms flre. Detection and tracking is by standard radar techniques, but identiflcation is carried out by exciting the projectiles Complex Natural Resonances and using this aspect independent information to assign a caliber to the incoming projectiles. The typical sizes of small arms projectiles (calibers 5.56mm through to 13mm) imply that ultra wide band illumination in the microwave region of the spectrum between 1.5{5.5GHz is required to excite these object's fundamental resonances. The authors give a discussion of the efiects of motion on the quality of the complex natural resonance data obtainable and present both simulated and laboratory data for the radar cross section of three difierent caliber projectiles (5.56mm, 7.62mm and 13mm).

Toxicological Responses of Red-Backed Salamander (Plethodon cinereus) Exposed to Aged and Amended Soils Containing Lead

The use of lead in military and civilian small arms projectiles is widely acknowledged to have resulted in high soil lead concentrations at many small arms ranges. These ranges are often adjacent to wildlife habitat or have become habitat when no longer used. To assess the potential toxicity of lead to terrestrial amphibians in contaminated areas, we exposed 100 red-backed salamanders (Plethodon cinereus) to either a control soil or one of four soil treatments amended with lead acetate for 28 days. Analytical mean soil concentrations were 14 (control), 553, 1700, 4700, and 9167 mg Pb/kg soil dry weight. An additional 60 salamanders were also exposed for 28 days to one of six field-collected soil samples from a small arms range and a skeet range. The field soil concentrations ranged from 11 (background) to 16,967 mg Pb/kg soil dry weight. Food consisted of uncontaminated flightless Drosophila melanogaster. Salamander survival was reduced in amended soil treatments of 4700 and 9167 mg/kg by 15% and 80%, respectively. Inappetence was observed at 4700 and 9167 mg/kg and growth decreased in the 9167 mg/kg treatment. Total white blood cells decreased 32% at 4700 mg/kg compared to controls and were 22% lower in the 9167 mg/kg treatment. In contrast, survival was 100% for all field-collected soils with no hematological effects. At 16,967 mg/kg there was evidence of soil avoidance and decreased growth. These data suggest marked differences in toxicity and bioavailability of the lead-amended soil in contrast to the field-collected soil containing lead.

Perforation resistance of five different high-strength steel plates subjected to small-arms projectiles

Thin plates of high-strength steel are frequently being used both in civil and military ballistic protection systems. The choice of alloy is then a function of application, ballistic performance, weight and price. In this study the perforation resistance of five different high-strength steels has been determined and compared against each other. The considered alloys are Weldox 500E, Weldox 700E, Hardox 400, Domex Protect 500 and Armox 560T. The yield stress for Armox 560T is about three times the yield stress for Weldox 500E, while the opposite yields for the ductility. To certify the perforation resistance of the various targets, two different ballistic protection classes according to the European norm EN1063 have been considered. These are BR6 (7.62 mm Ball ammunition) and BR7 (7.62 mm AP ammunition), where the impact velocity of the bullet is about 830 m/s in both. Perforation tests have been carried out using adjusted ammunition to determine the ballistic limit of the various steels. In the tests, a target thickness of 6 mm and 6 + 6 = 12 mm was used for protection class BR6 and BR7, respectively. A material test programme was conducted for all steels to calibrate a modified Johnson–Cook constitutive relation and the Cockcroft–Latham fracture criterion, while material data for the bullets mainly were taken from the literature. Finally, results from 2D non-linear FE simulations with detailed models of the bullets are presented and the different findings are compared against each other. As will be shown, good agreement between the FE simulations and experimental data for the AP bullets is in general obtained, while it was difficult to get reliable FE results using the Lagrangian formulation of LS-DYNA for the soft core Ball bullet.

Influence of boundary conditions on the ballistic performance of high-strength fabric targets

High-strength fabric is commonly used in personnel protection systems against small arms projectiles and fragments. An understanding of the characteristics of high-strength fabric under ballistic impact would provide useful insights for fabric armor design. A numerical model is formulated and used to study the perforation of square plain-woven fabric targets when the fabric is (i) clamped along all four edges with its yarns aligned parallel to the edges, (ii) clamped along all four edges with yarns running 45° to the edges and (iii) clamped along two edges with yarns aligned parallel to the edges. In addition, high-speed ballistic tests are carried out to validate the computational results. It is found that the ballistic resistance of such systems is sensitive to boundary conditions and yarn orientation. Targets that are unclamped on two edges can absorb more impact energy than those with all four sides clamped. Orientating the yarns 45° to the clamped edges can improve energy absorption significantly. Stresses in primary yarns (those in contact with the projectile) increase rapidly when their ends are clamped; this leads to rapid failure at the impact point and a lower energy absorption. For fabrics clamped along four edges, the regions near the four corners are not stretched during impact if the yarns are parallel to the edges, whereas clamping with the yarns 45° to the edges facilitates energy dissipation by the entire fabric. It is also observed that slippage at clamped edges contributes to higher energy absorption by fabric targets.

Lead Isotope Ratio Determination for the Forensic Analysis of Military Small Arms Projectiles

A study focusing on the ability to utilize isotopic analysis of Pb used in small arms projectiles from varying geographic origin was undertaken using the GV Instruments Isoprobe multicollector inductively coupled plasma mass spectrometer. With the exception of two classes of ammunition, these samples were able to be distinguished from one another. Also, following rigorous normalization and mass bias correction, these data were compared to data collected by geochemists in localities corresponding to projectile manufacture. This comparison was successful when projectiles in certain economically isolated countries were analyzed. Pb isotopic analysis with MC−ICPMS is shown to be useful as a tool for distinguishing between ammunition of various manufacturing origins.

On the physics of momentum in ballistics: Can the human body be displaced or knocked down by a small arms projectile?

Shooting incidents are often portrayed as resulting in a sometimes violent backwards displacement of the victim. This opinion is also not infrequently held by expert witnesses. The physical force responsible for this would be momentum (mass x velocity). The physics of momentum in ballistic injury is explained in detail. The maximum momentum transferred from different small arms projectiles including large calibre rifles and a 12-gauge shotgun only results in a backwards motion of a 80 kg target body of 0.01-0.18 m/s, which is negligible compared to the velocity of a pedestrian (1-2 m/s). Furthermore, counterbalance is constantly maintained by neurophysiological reflexes. So the effect of the momentum transferred from the missile is virtually zero and there is no backwards motion of the person shot. Empirical evidence verifying these calculations can be obtained from hunting big game, from human gunshot victims and from a video documentary demonstrating the lack of any backwards motion of a person wearing body armour after hits from a centre fire rifle. So the alleged backwards hurling of a person shot is nothing but a myth which should be refuted not only because it is incorrect but also because it can result in miscarriages of justice.

Protective Ability of the Standard U.S. Military Personal Armor System, Ground Troops (PASGT) Fragmentation Vest Against Common Small Arms Projectiles

This study analyzes the ballistic protection provided by the standard U.S. Military Personal Armor System, Ground Troops fragmentation vest against threats from handgun and shotgun projectiles. Damage assessment was conducted using 10% ordnance gelatin, a tissue simulant which has been proven to have a close correlation with living tissue. The standard fragmentation vest was shown to provide protection from commonly encountered handgun bullets and shotgun pellets, but not from shotgun slugs or center-fire rifle bullets.

Design of SFRC barriers against impact of small arms projectiles

In this paper we present some results from a work developed in order to get some rational design method of SFRC against the impact of small projectiles. Firstly, we describe the way through which trials were done. Second, we present the principal results of this work. Based on it, a model is proposed to calculate both penetration depth of the projectile if it is not to perforate and residual velocity if it is to perforate, as well as perforation or scabbing threshold thicknesses. Owing to its physical basis and overall principles its application goes beyond -at least at the beginning- the field of steel fiber reinforced concrete. 1. Plates