Full Metal Jacket Projectile Research Articles

Experimental and Numerical Analysis of the Damage Mechanism of an Aramid Fabric Panel Engaged in a Medium-Velocity Impact.

The aim of this study is to analyze the ballistic impact behavior of a panel made of Twaron CT736 fabric with a 9 mm Full Metal Jacket (FMJ) projectile. Three shots are fired at different velocities at this panel. The ballistic impact test procedure was carried out in accordance with NIJ 010106. The NIJ-010106 standard is a document that specifies the minimum performance requirements that protection systems must meet to ensure performance. The 9 mm FMJ projectile is, according to NIJ 010106, in threat level II, but the impact velocity is in threat level IIIA. Analysis of macro-photographs of the impact of the Twaron CT736 laminated fabric panel with a 9 mm FMJ projectile involves a detailed examination of the images to gather information about the material performance and failure mechanisms at the macro- or even meso-level (fabric/layer, thread). In this paper, we analyze numerically and experimentally a panel consisting of 32 layers, made of a single material, on impact with a 9 mm FMJ projectile. The experimental results show that following impact of the panel with three projectiles, with velocities between 414 m/s and 428 m/s, partial penetration occurs, with a different number of layers destroyed, i.e., 15 layers in the case of the projectile velocity of 414 m/s, 20 layers of material in the case of the panel velocity of 422 m/s and 22 layers destroyed in the case of the projectile velocity of 428 m/s. Validation of the simulated model is achieved by two important criteria: the number of broken layers and the qualitative appearance. Four numerical models were simulated, of which three models validated the impact results of the three projectiles that impacted the panel. Partial penetration occurs in all four models, breaking the panel in the impact area, with only one exception, i.e., the number of layers destroyed, in which case the simulation did not validate the validation criterion. The performance of Twaron CT736 fabric is also given by the indentation depth values by two methods: according to NIJ 0101.06 and by 3D scanning. The NIJ 010106 standard specifies that a panel provides protection when the indentation depth values are less than 0.44 mm.

Ballistic behaviour of hybride carbon/basalt fiber reinforced epoxy-hBN composite

Ballistic behaviours of hybrid composite armors were investigated through experiments. The effects of hexagonal boron nitride (h-BN) nanopowders and number of layers on ballistic performance were examined. Four types of armors were manufactured by hand lay-up and vacuum bagging technique: 60 layers of fabric (30 layers carbon and 30 layers basalt fabrics) with 0% h-BN (1-A) and 1% h-BN (1-B), also 100 layers of fabric (50 layers carbon and 50 layers basalt fabrics) with 0% h-BN (2-A) and 1% h-BN (2-B) with epoxy resin. Ballistic impact tests were performed on the armors using a 9 mm full metal jacket projectile. The densities of the ballistic plates are 1.53, 1.56, 1.61 and 1.65 respectively. After three shots to each plate, the average hole depths were 5.55 mm on the 1-A coded plate, 4.34 mm on the 1-B armor, 4.68 mm on the 2-A plate, and 4.69 mm on the 2-B armor. All of the armors were able to confront for the velocities between [Formula: see text] m/s successfully. However, the h-BN showed a significant influence on the overall ballistic performance of composite armors. It has been found that the penetration depth decreases with the addition of h-BN. Also SEM-EDS mapping and XRD analysis were used to characterize the hybrid composites.

Mechanical analysis of helmeted headforms under ballistic impact with implications in performance evaluation of ballistic helmets

Behind helmet blunt trauma is a significant health concern in modern warfare. The ballistic response of the human head under ballistic impact is highly sought. Towards this end, we conducted ballistic experiments on three different headforms. The following headforms were considered: a) National Institute of Justice based rigid headform, b) Hybrid-III based flexible headform, and c) head model based headform. Headforms b, c were assembled with the Hybrid-III neck. An advanced combat helmet was fitted to the headforms. Helmet-head assembly was subjected to a 9 mm × 19 mm full metal jacket projectile having velocities of 430 ± 15 m/s. The response of the head surrogate in the front, back, side, and crown orientations was studied. Back face deformation (BFD), head kinematics, and intracranial pressures in headforms were measured. In addition, equivalent stress and maximum principal strain in the brain were obtained using concurrent finite element simulations. Results suggest that both local (i.e., due to the localized crushing of the helmet) and global (i.e., due to the bulk motion of the helmet-head parenchyma) responses were dominant under investigated ballistic impacts. Further, the type of the headform affected the biomechanical response. As compared to the rigid headform, a statistically significant increase in head kinematics was observed with the flexible headforms; changes in BFD were statistically insignificant. The orientation dependent responses have been observed. Overall, these results provide novel insights regarding the ballistic response of the headforms with the combat helmet and underscore critical considerations during the ballistic evaluation of helmets.

PERFORATION AND PENETRATION OF FIBER METAL LAMINATES TARGET BY HEMISPHERICAL PROJECTILE

This study aims to examine the phenomena that occur due to projectile penetration on fiber metal laminate. Ballistic testing was carried out experimentally according to National Institute of Justice standards (NIJ Standard 0101.06 level III-A) using a 9 mm full-metal jacket projectile with a normal angle of attack (90° to the target). The results showed that fiber metal laminate could withstand the projectile rate by penetrating the first layer (aluminum plate) and the second layer (aramid/epoxy), while the last layer was deformed to form a bulge. The pierced aluminum plate is characterized by petalling failure. Meanwhile, the aramid/epoxy was penetrated by the projectile with failure of the primary yarn to break the fiber.

Evaluation of Projectile Penetration Position on Perforated Plate on Ballistic Resistance of Composite Sandwich Panels

This paper evaluates the performance of perforated plates in composite sandwich panel under high-velocity impact. The ballistic resistance of composite sandwich panels made of steel plate on the outer layer and the rubber on the middle layer was evaluated using experimental and numerical methods. The front plate is modified with 3 mm diameter of holes, and the distance between the holes is 10 mm. Experimental testing was carried out by firing a 9 mm full metal jacket projectile at a distance of 5 m and an angle of attack of 90° on the target. Experimental results and numerical simulations show that the position of the projectile penetration at the side of the hole in the composite panel stops the projectile velocity faster at 1.1619 x 10−4 s with a maximum energy absorption of 532.9 J than at center of hole and middle of four holes. The failure of the side of the hole penetration position is the asymmetrical deformation of the back plate due to changes in the penetration position of the projectile with the initial trajectory, fractural projectile core and brass jacket projectile erosion. The projectile penetrates the front plate due to plastic deformation, and rubber in the middle layer is pushed and perforated in the projectile direction, causing the back plate to form a bulge.

Can Synbone® cylinders and deer femurs reproduce ballistic fracture patterns observed in human long bones?

Whereas gunshot injuries in human craniums have been well studied, reliable data on fracture patterns in ballistic long bone trauma remains scarce. Further information useful for forensic trauma interpretation and reconstruction may be retrieved from experimentally produced gunshot fractures. In order to avoid the use of human specimens for experimental research, it is of great interest to determine whether alternative models can reproduce the ballistic fracture patterns of human long bones. To address this question, we shot seven healthy adult human femurs and humeri each, ten samples each of two different polyurethane cylinders from Synbone® and four femurs from female red deer. The specimens were embedded in ballistic gelatin and perpendicularly shot from a distance of 2 m, using a 9-mm full metal jacket projectile at an impact velocity of 360 m/s. The macroscopical appearance of the detailed fracture pattern considering entry, exit and general cortical traits as well as the bullet’s energy lost upon impact were compared between the models. Despite some general similarities, neither of the two alternative models entirely reproduced the fracture patterns of human long bones. Comparing the two alternative models, the surrogate model revealed more significant differences to the human fracture than the animal model. This leads to the conclusion that the polyurethane material provides a different failure mechanism than real bone, underpinning the challenge in deploying an accurate analog.

Efficient design of Kevlar/basalt hybrid composite laminates under ballistic impact

Advanced composite materials such as Kevlar and basalt are most commonly used for the efficient design of body armor to predict the safety and reliability of the armor systems. The aim of this study is to develop the lightweight and efficient design of armor plate using the 3D Kevlar/basalt hybridization and different stacking sequences of composite laminates impacting with two impactors under high-velocity impact. Damage initiation and damage propagation based on the Yen criteria are developed to investigate the different failure modes of composites. The hybrid composite panels are modeled using 3D solid element considering the four different types of panels such as H3B3, H3K3, B3K3 and K3-16 impacting with fragment simulating projectile (FSP) and 9 mm full metal jacket(FMJ) projectiles. The efficient design of hybrid panel B3K3 showed excellent ballistic performance parameters in comparison to the other hybrid panels designed under the FSP and FMJ projectiles.

Numerical and experimental investigation on 3D angle interlock woven fabric under ballistic impact

3D woven fabric has great potential applications in body armor due to its good mouldability. This paper reports the ballistic mechanism of 3DAWF under the Full Metal Jacket (FMJ) projectile impact. Numerical simulation of 3DAWF under ballistic impact employing strain rate effect material models was established to capture the yarns’ behaviors under high-speed impact loadings. Membrane elements construct a full-size mesoscale model based on real 3DAWF structure to improve computational efficiencies. The ballistic impact tests of 3DAWF subjected to the FMJ projectile were carried out to validate and evaluate the finite element analysis (FEA) model. From the results of the tests and theoretical model, it was found that the FEA model exhibits a relatively good correlation with tests on residual velocities, deformation, and damages. This work revealed the impact damage evolution, energy absorption mechanism, and the stress wave distribution in the 3DAWF, and the findings are instructive for the design of 3DAWF for ballistic protection.

Ricochet quantification using a multiple sensor approach

This study investigates the ricochet behaviour of three different small-arms projectile types using a novel ricochet measuring device. The results can be used to estimate the danger potential of ricochets on shooting ranges.A ricochet is the change of direction and velocity of a projectile after impacting an oblique surface. This impact produces strong vibrations on a rigid plate.During this impact, flexural waves travel radially outwards from the point of impact. These waves are used to determine the properties of the impactor with accelerometers situated on the target surface. With the use of two measurement plates, one can produce a ricochet and detect the velocity at the same time.Accelerometers are suitable for accurate momentum measurements of single impacts. However, depending upon strike velocity and the impact angle, a ricochet can separate in multiple fragments after being deflected. From the operational safety perspective, these fragments need to be detected, as well. The approach of a coupled sensor concept was chosen to solve this problem.Thermographic sensors were additionally used to visualise the heat which is produced after penetrating a rubber layer pasted in front of the steel target plate. With this approach one was able to detect the position of impact. The investigations showed that the measurement system performance is better with a multiple sensor design, which includes accelerometers for the velocity, impact strength and partly the position measurement, while the thermographic sensor was used for the position measurement and partly the momentum measurement.The investigated ammunition showed plausible fragmentation behaviour, and the results can already be used to estimate the danger potential of different ammunition types. Frangible projectiles fragment to small particles already after being deflected under a small angle. However, Full Metal Jacket projectiles with or without a steel core do not fragment under angles which are less than 5°.The objective of the paper is to demonstrate the possibility of measuring the complex ricochet mechanics of small projectiles using standard accelerometers with the adequate signal processing approach. This measuring system is supported by an off the shelf thermographic camera.

Projectile Impact Resistance of UHPFRC Structures for Various Methods of Fresh Mixture Placement

This paper present results of an experimental investigation of the projectile impact resistance of ultra-high-performance fibre-reinforced concrete (UHPFRC) slabs. The paper also investigates transparent viscous liquid, based on the ultrasound gel, as an effective suitable tool to replace fresh mixture of ultra-high-performance concrete. The description of the viscous behaviour of both materials and optimisation of the ultrasound gel is shown. An arrangement of fibres in the UHPFRC mixture was demonstrated by the ultrasound gel with an addition of steel fibres. The influence of horizontal and vertical casting of thin slabs against penetration by a projectile was tested and described. The resistance to the penetration was investigated using full-metal jacket projectile with soft-lead core. The results indicated various penetration depths and crater diameters in the target specimens for both methods of casting. Various methods of casting resulted in various arrangement of fibres for both horizontally and vertically casted slabs. However, the protective capacity was guaranteed for both placement methods. The desired outcome was determination of the UHPFRC mechanical properties and projectile impact resistance, depending on the orientation of fibres which depended on the method of placement of the fresh mixture into the formwork. The direction of mixture placement into the formworks had a significant impact on achieved mechanical properties of the hardened concrete. Based on the present findings it was found that slabs from ultra-high-performance fibre-reinforced concrete casted horizontally appear to be more efficient in protection against projectile impact.

Ballistic impact response of Kevlar® reinforced thermoplastic composite armors

The ballistic impact response of thermoplastic-based composite armors made from Kevlar® fabric and polypropylene (PP) matrix has been investigated against ballistic test standard NIJ-STD 0106.01 Type IIIA. Kevlar® fabrics of different architectures, namely 2D plain woven, 3D orthogonal and 3D angle interlock fabrics, were produced and used as reinforcements to fabricate composite armor panels, using compression molding technology. Interfacial property between PP and Kevlar® was improved by adding a coupling agent called maleic anhydride grafted PP. Reduced density was observed in Kevlar® thermoplastic-based composites as compared to that of the thermoset-based laminates. Ballistic impact tests were imparted with 9 mm full metal jacket (FMJ) on armor panels having different fabric architecture. Ballistic test results revealed that 2D armor was 2.4–7% more susceptible to damage than 3D armors. Hydrocode simulations were carried out using ANSYS AUTODYN v. 14.0 to obtain an estimate for the ballistic limit velocity and simulate failure modes. Post-impact damage patterns obtained from the simulations were compared with the experimental results to assess the performance of the simulations. Good correlation between the hydrocode simulations and experiments was found, both in terms of failure modes and damage patterns. 3D composite armors were able to confront the 9 mm FMJ projectile; however, the 2D plain woven armors failed. The increase in the ballistic limit from 2D plain woven armor to 3D orthogonal and 3D angle interlock armors was 16.44% and 20%, respectively, indicating the effect of fabric architecture.

Experimental model for civilian ballistic brain injury biomechanics quantification

Biomechanical quantification of projectile penetration using experimental head models can enhance the understanding of civilian ballistic brain injury and advance treatment. Two of the most commonly used handgun projectiles (25-cal, 275 m/s and 9 mm, 395 m/s) were discharged to spherical head models with gelatin and Sylgard simulants. Four ballistic pressure transducers recorded temporal pressure distributions at 308 kHz, and temporal cavity dynamics were captured at 20,000 frames/second (fps) using high-speed digital video images. Pressures ranged from 644.6 to −92.8 kPa. Entry pressures in gelatin models were higher than exit pressures, whereas in Sylgard models entry pressures were lower or equivalent to exit pressures. Gelatin responded with brittle-type failure, while Sylgard demonstrated a ductile pattern through formation of micro-bubbles along projectile path. Temporary cavities in Sylgard models were 1.5–2× larger than gelatin models. Pressures in Sylgard models were more sensitive to projectile velocity and diameter increase, indicating Sylgard was more rate sensitive than gelatin. Based on failure patterns and brain tissue rate-sensitive characteristics, Sylgard was found to be an appropriate simulant. Compared with spherical projectile data, full-metal jacket (FMJ) projectiles produced different temporary cavity and pressures, demonstrating shape effects. Models using Sylgard gel and FMJ projectiles are appropriate to enhance understanding and mechanisms of ballistic brain injury.

Dynamic X-ray imaging of the penetration of boron carbide

The U.S. Army Research Laboratory has adapted two 1-MeV x-ray pulsers to obtain multiple dynamic, real time x-rays of the impact of 7.62-mm APM2 armor-piercing projectiles on a boron carbide ceramic. The goal was to conduct a high fidelity diagnostic analysis of the impact during the initial transient period and document the penetrator/target interaction. Three conditions ofthe projectile were tested: the full metal jacket projectile; the steel core and lead tip only; and just the steel core. These different conditions allow the observation of the tip breakup mechanism and determination of the average penetration velocity, the time for initiation of rigid body penetration into the ceramic/backing and the ballistic contributions of the projectile components.

Comparison of the Terminal Ballistics of Full Metal Jacket 7.62-mm M80 (NATO) and 5.56-mm M193 Military Bullets: A Study in Ornance Gelatin

Great controversy has surrounded the replacement of the 7.62-mm caliber by the reduced 5.56-mm caliber as the standard U.S. military rifle. Although its relevance to human wounding can be debated, the terminal ballistics of military small arms in ordnance gelatin remains a convenient medium for comparative testing. In the present study, 7- by 10- by 24-in. (18 by 25 by 61 cm) blocks of 20% ordnance gelatin were fired upon from a range of 19 ft (6 m) under high-speed cinemagraphic surveillance. The tendency of the M193 5.56-mm full metal jacket projectile to break up in soft tissue simulant was confirmed as a fundamental difference from the 7.62-mm M80 NATO ball.