Ballistic Material Research Articles

Experimental and numerical analysis of ballistic impat and material characterization of GFRP and Kevlar 29/epoxy composite laminate

Through experimental testing and numerical simulations, this study examines the effects of ballistic events on thin FRP composite laminated plates fabricated using a hand lay-up method. Experimental ballistic impact tests using a pneumatic gun are conducted on composite plates reinforced with woven glass and woven Kevlar 29 fibers. An advanced three-dimensional finite element model programed in Ansys/Autodyn v19.1 is employed to verify the experimental findings and analyze the ballistic perforation characteristics of the target. The crucial material constants needed for the constitutive material model used in the simulation are acquired through precise experimentation on samples prepared from the fabricated laminates. Significant agreement is observed between the FE simulations and experimental findings, particularly concerning the assessment of residual velocities of the projectile and damage pattern in the laminates. The results of this study show that when subjected to ballistic impact by a flat-ended cylindrical projectile, the thin woven FRP composite primarily experiences damage characterized by delamination, fiber breakage and matrix cracking. Additionally, based on current simulations, it is observed that the ballistic limit velocity of the Kevlar 29/epoxy laminate exceeds that of GFRP by 25.64% when both materials have an equal thickness of 2.8 mm.

Gamma-Ray Burst Pulses and Lateral Jet Motion

We propose that gamma-ray burst (GRB) pulses are produced when highly relativistic jets sweep across an observer’s line of sight. We hypothesize that axisymmetric jet profiles, coupled with special relativistic effects, produce the time-reversed properties of GRB pulses. Curvature resulting from rapid jet expansion is responsible for much of the observed pulse asymmetry and hard-to-soft evolution. The relative obliqueness with which the jet crosses the line of sight explains the known GRB pulse morphological types. We explore two scenarios: one in which a rigid/semirigid jet moves laterally and another in which a ballistic jet sprays material from a laterally moving nozzle. The ballistic jet model is favored based upon its consistency with standard emission mechanisms.

Products and dynamics of lava-snow explosions: The 16 March 2017 explosion at Mount Etna, Italy

Volcanic hazards associated with lava flows advancing on snow cover are often underrated, although sudden explosions related to different processes of lava-snow/ice contact can occur rapidly and are only preceded by small, easily underrated precursors. On 16 March 2017, during a mildly effusive and explosive eruption at Mount Etna, Italy, a slowly advancing lava lobe interacted with the snow cover to produce a sudden, brief sequence of explosions. White vapor, brown ash, and coarse material were suddenly ejected, and the products struck a group of people, injuring some of them. The proximal deposit formed a continuous mantle of ash, lapilli, and decimeter-sized bombs, while the ballistic material travelled up to 200 m from the lava edge. The deposit was estimated to have a mass of 7.1 ± 0.8 × 104 kg, which corresponds to a volume of 32.0 ± 3.6 m3 of lava being removed by the explosion. Data related to the texture and morphology of the ejected clasts were used to constrain a model of lava-snow interaction. The results suggest that the mechanism causing the explosions was the progressive build-up of pressure due to vapor accumulation under the lava flow, while no evidence was found for the occurrence of fuel-coolant interaction processes. Although these low-intensity explosions are not particularly frequent, the data set collected provides, for the first time, quantitative information about the processes involved and the associated hazard and suggests that mitigation measures should be established to prevent potentially dramatic accidents at worldwide volcanoes frequented by tourists and with fairly easy access, such as Etna.

Plywood Panel with UHMW Polyethylene Board Ballistic Resistance

In this study, bullet-proof building panels are investigated. The aim of this work is to verify whether the polyethylene-plywood panels withstand frontal impact with high-speed projectiles. Ultra-high molecular weight polyethylene (UHMWPE) is a promising ballistic material due to its favorable properties – significant impact toughness and a high strength-to-weight ratio, meantime it is lightweight. By setting different parameters such as laminated plywood width and various UWHMPE facade layers, the protective effect of the panels and their performance characteristics are discussed using a 9 mm caliber handgun Glock 17 Luger bullets. The results show positive results – 3 of 4 combinations resist the bullet. The board with an arrangement of 2x32 cm laminated plywood outside and UHMWPE material inside the room captures 4 bullets; the bullets pass through the plywood layer and stop in the polyethylene. The experiment also tested individual UHMWPE panels at 2 different thicknesses to monitor the damage to the material. The results of this study will be useful in designing ballistic panels for buildings like unclassified buildings (army headquarters, safe rooms) from small arms weapons also for individual use.

Energy balance model to assess the resistance of ballistic protection materials

NATO standards "AEP-2920 Procedures for the Evaluation and Classification of Personal Armor" and NIJ Standard – 0101.06, indicate the method to statistically assess the resistance of personal ballistic protection materials. To be validated and accepted through these procedures, a personal ballistic protection material should withstand an impact of a specific projectile with a probability of a partial penetration confidence level higher than 90%. The present study introduces an energy equilibrium method to assess the confidence level for the probability of partial penetration of ductile and brittle materials. The experiments performed in the Ballistics laboratory of the Royal Military Academy in Belgium, use a modified pendulum method that allowed the quantification of the energy balance before and after the ballistic impact. The results were then compared with the ones obtained using the method specified by the NATO standard and NIJ 0101.06, mentioned above. The outcome of this comparison shows the tendency of the values obtained by the pendulum method to faithfully follow the values obtained according to NATO and NIJ specifications. The presented method is not based on statistical estimations, but instead, an exact method, of computing the energy absorbed by the tested material. This is an advantage for the cases when the material to be evaluated is expensive or it is in the development phase and mass production is not possible.

Graphene Nanoplatelets on Multi-Scale Polymer Composites for Potential Ballistic Shielding

Continuous development, improvement and innovation of ballistic material systems with superior energy absorption performance has been the subject of numerous works nowadays. Some research has been carried out with the objective of replacing traditional metallic and ceramic materials and composites with high-performance polymeric composites. Due to their excellent properties, multi-scale polymer composites have been used in the most varied segments of the industry, being recently researched in applications such as ballistic materials. This work promotes the combination of high-strength three-dimensional woven aramid fiber fabrics with vinyl ester resin to produce a panel through the compression molding process. The resin was reinforced with graphene nanoplatelets (0.1, 0.2 and 0.3% wt). The impact, tensile and flexural strength were evaluated, along with dynamic-mechanical analysis by DMA and by Hopkinson split bar test, indicating a trend of better performance for the composite containing 0.1% of graphene nanoplatelets.

Exploration of disentangled UHMWPE tape as a soft body armour material

Disentangled ultrahigh molecular weight polyethylene (UHMWPE) is a very promising material with extremely high tenacity and modulus. In this work, the effect of drawing on the morphological, physical, and mechanical properties of disentangled UHMWPE tapes was studied. The tapes were characterised by using the density gradient column method , wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), polarised optical microscopy and scanning electron microscopy (SEM). The density and crystallinity of tape improved after each stage of drawing. The unoriented crystalline structure of the as-prepared UHMWPE tape gradually transformed into an oriented crystalline structure on drawing as confirmed by WAXD patterns. As the draw ratio increased, concomitant increase in birefringence, and tensile properties were also noticed. The tape obtained after the final stage of drawing had tensile properties similar to that of gel spun UHMWPE fibres. Hence, this tape was used to make prototype of soft armour panel (SAP) that stopped all the bullets fired when subjected to ballistic test and yielded very low back face signature (BFS) justifying the potential of disentangled UHMWPE tape as a ballistic material.

Influence of induction hardening on the damage tolerance of EA4T railway axles

Induction hardening, a more efficient and effective surface hardening technique of railway axles, has received considerable attention for its potential of replacing deep rolling to be the surface strengthening technique of EA4T axles. In order to establish guidance for industrial utilization of induction hardened railway axles, damage tolerance assessment on induction hardened EA4T axles is a necessity. The purpose of this paper is to evaluate the influence of induction hardening on the damage tolerance of EA4T axles subjected to flying ballast impact damage. Impact damages were introduced artificially by means of shooting balls of 2 mm in diameter to induction hardened specimens and untreated ones. The damage modes of two kinds of specimens were analyzed and the resultant loading capacity debit was evaluated. Based on the characterization of damages and fracture surfaces, failure mechanisms were discussed. Due to the high strength of hardened layer, it is more significant to resist plastic deformation under a moderate impact. Under ballistic impact, microcracks, material loses and adiabatic shear bands (ASBs) present in damage of hardened specimen. Fatigue strength of smooth hardened specimen was improved by 61 % in comparison with that of untreated one. As a result of stable and considerable compressive residual stress of induction hardened (IH) specimen, fatigue strength of damaged hardened specimen is markedly larger than the as received (AR) ones with similar defect size.

Review of ballistic protection materials: Properties and performances

Ballistic clothing is a crucial safety element that helps to save lives of its wearers. According to the protection level, the ballistic vest is reinforced by one or two armor panels designed to resist to attacks destinated to upper parts of the body. The resistance behavior of ballistic body armor depends on several factors. The most important factors are related to the ballistic fabric properties such as the type of fabric, its thickness, its structure, its strength and strain, and the type of the employed resin. In this review paper, the factors influencing the ballistic performances of soft armor panel and hard armor panel are presented. They are investigated based on an in-depth review of previous research studies and experimental test results. This paper also reports the various methods developed by the researchers to improve the performance of ballistic materials. Thus, ballistic material manufactures and researchers could find some guidelines on promising materials and structures that can be used to build efficient body armors.

Pengembangan Baja Paduan Tahan Peluru Melalui Proses Hot-Forging Terhadap Morfologi Dan Sifat Mekanik

Laterite steel is steel that has a nickel content of up to 2%. The nickel content can produce steel with superior properties such as: high strength, corrosion resistance, and good weldability properties. With the superior nature of laterite steel is needed in the main tool of the indonesian national tantara weapon system. To find out the performance of damage to bulletproof materials, then conducted research on this laterite steel as a tough armour material by conducting research in the form of mechanical properties testing (Hardness, and Impact) and microstructures (Metalography). Samples are prepared in accordance with ASTM standardization. Based on the results of the hardness test, the average values of F and T samples were 663.9 HVN and 170.7 HVN. Material F qualifies as a ballistic resistant material (armour) because the hardness obtained in accordance with the classification and can withstand bullet penetration well. Then the impact test obtained the average value of the F and T samples is 9 joules and 148 joules. For F samples, the type of fault is a granular fracture and a T sample of the type of fault is a tenacious fracture. As a result of metallographics, sample F has a corrected phase is upper bainite as a matrix and martensite is generally shaped like a fine needle. Then the T sample has a formed phase is dominated by ferrite with soft and tenacious properties. As well as perlite as a matrix with quite hard and strong properties.

Experimental Study of Action Different Kinetic Energy on the Colon

The purpose of the study. To increase the effectiveness of surgical care for the wounded with combat trauma of the colon by studying of ballistic, morphological and functional features of the gunshot wounds. Patients and methods. A study of surgical treatment of 83 wounded with combat injuries of the colon, received in the area of anti-terrorist operation in the period from 2014–2018. For comparative analysis of treatment results, two clinical groups were formed: comparison and main. The comparison group included 42 wounded who were treated from April 2014 to February 2015 (the first and second periods of ATO), who used traditional surgical tactics. The main group included 41 wounded who were treated from March 2015 to 2018. Results. Analysis of the distribution of wounded with combat trauma by type of wound / injury revealed that the vast majority of them in both groups had shrapnel wounds – 49 (59.1%). There were 30 (36.1%) victims with bullet wounds, and 4 (4.8%) with closed injuries. The wounded patients with the battle trauma of the thick bowel by type of injury had missile wounds as a rule – 49 (59.1%). There were 30 (36.1%) patients with bullet wounds, and 4 (4.8%) with closed injuries. Most of the injuries were combined – 58 (69.9%), and with only abdominal injuries – 25 (30.1%), mostly multiple – 21 (25.3%). The great majority of the thick bowel injuries belonged to sigmoid – 32 (38.6%) and transverse colon – 21 (25.3%), which is explained by relatively large size of these parts of the intestine. Conclusions. The choice of surgical tactics and scope of surgical interventions on damaged organs and structures took into account the results of experimental study of mechanogenesis and pathomorphology of gunshot wounds of the colon, obtained in bench studies by modeling gunshot wounds on “thoracoabdominal ballistic material”.

Results of experimental research of wound ballistics of separate types and calibers of modern bullets

There was made the analysis of wound ballistics of modern expansive bullets in comparison with shell bullets on 25 blocks of ballistic plasticine (ROMA PLASTILINA No. 1, Ballistic Testing Backing Material), made in the USA, in which one shot from an AKS-74 automatic firearm and carbine ZBROYAR Z-10 with an optical sight was fired. The bullet speed was the highest in 5.45x39 caliber cartridge with a V-max bullet. – 1185 m/s, low in the bullet caliber cartridge .308 Win with a bullet SP, – 664 m/s. The difference is significant at the level of significance α=0.05. In terms of the size of the entrance hole, the largest is from the bullet of cartridge .308 Win with a bullet SP – 10.0 cm, the smallest - from the bullet "PS" with a steel core 5.45x39 mm, cartridge sample of the year 1974 (7H6) – 1.2 cm. The difference is significant at the level of significance α=0.05. In the expansive bullet of type "V-Max" of shortgun cartridge of caliber 5.45x39 mm, the size of the entrance hole was 9.1 cm, with asterial shape having radial gaps and turned edges of ballistic plasticine on the outside. All cartridges with expansive bullets did not have an exit hole after the shot. The dimensions of the formed residual cavity were the largest after firing with .308 Win caliber cartridge with a bullet SP – 25.0x5.0 cm., the smallest – bullet of a military caliber cartridge of 5.45x39 mm (7H6) – 6.0x4.0 cm. The difference is significant at significance level α=0.05. The shape and character of the residual cavity in ballistic plasticine was significant for all expansive bullets, in contrast to the bullet of a military cartridge 5.45x39 mm (7H6), where no such changes are detected. The considerable signs of expansion properties and deformation of the bullet in the form of a "flower of death" were identified in the bullet of caliber cartridge .308 Win with a bullet SP, other bullets with expansive properties showed significant fragmentation, with the location of fragments both in the residual cavity and outside its borders at different distances. Expansive bullets differ significantly at the level of significance α=0.05. The low flight speed of bullets (m/s) of .308 Win caliber cartridges with bullets BTHP and SP is due to their structure, weight, and caliber. Bullet of type V-max with cartridge 5.45x39 mm has the highest speed – 1185 m/s, and due to its design has significant expansive properties. Common to expansive bullets is a entrance hole, the blind nature of the lesion with the presence of a large residual cavity, which is due to kinetic energy return 114.37 E, J/mm2 inside the object of lesion. Fragmentation of expansion bullets occurs inside an object with fragments located at different distances. A .308 Win caliber cartridge with SP bullet causes deformation of s bullet by the type of "death flower" causing significant damage.

Study of dynamic compressive responses of ultra‐high molecular weight polyethylene felt impregnated with shear thickening fluid

AbstractIn this study, the effect of high strain rate on the dynamic mechanical properties of shear thickening fluid (STF) impregnated felt of ultra‐high molecular weight polyethylene (UHMWPE) was investigated by split‐hopkinson pressure bar. UHMWPE felts are randomly oriented nonwoven fabric that holds each other due to inter‐fiber coupling either by thermal calendaring or mechanical entanglement. Its lower areal density and highly porous structure can be utilized in lightweight ballistic resistance material. The junction points inside its porous structure make it easier to hold abundant STF. Shear thickening fluid was prepared by dispersing 100 nm dry silica powder into polypropylene glycol at 67.5 wt% concentration using probe ultrasonicator at 25°C. Rheological characterization of prepared STF was conducted using MCR702 advanced Anton Paar rheometer. It was done by performing a steady shear rate and thixotropy tests for shear thickening and structural regeneration behavior. In‐house fabricated split‐hopkinson pressure bar setup was used to evaluate dynamic compressive behavior at different strain rates by changing triggering pressure. It was found that STF impregnated felt shows a higher amplitude of strain rate augmentation and energy absorption than a neat felt. The impact energy absorption increases with increasing strain rate. However, the peak stress shows an opposite trend with an increased strain rate in STF impregnated felt.

Frequency Scanning Conformal Sensor Based on SIW Metamaterial Antenna

A conformal transverse slotted substrate integrated waveguide (SIW) metamaterial leaky-wave antenna sensor with uniform slots is investigated and analyzed for mmWave sensing applications. Firstly, its planar version is introduced. Then, its performance is compared with the curved SIW antenna. The metamaterial characteristics of the antennas are investigated. The transverse slots on the array forms a composite right/left-handed (CRLH) metamaterial structure that controls the radiation direction as the function of frequency. It behaves like a left handed metamaterial and radiates backward in the lower frequencies of the band (28-45GHz), whereas it behaves like a right handed metamaterial that scans forward direction at the higher frequencies (45-62GHz). Approximately 80° beam scanning is obtained in curved version with acceptable side lobe levels, whereas 110° beam steering is achieved with the planar version. Theoretical analysis and the simulation results are confirmed successfully by the experimental results in the 28-40 GHz band. Besides, a practical example of conformal SIW metamaterial antenna on military helmet made of a ballistic material is illustrated. The calculated spatial peak power density values of the proposed curved SIW metamaterial antenna on the outer surface of a head phantom are demonstrated.

Analysis of thermal anomalies at Copahue Volcano between October 2011 and the December 2012 eruption with MODIS

Copahue volcano is an active stratovolcano located in the Southwest of the Agrio-Caviahue depression in the Province of Neuquén at the border between Argentina and Chile, and the most recent eruptive activity involved five cycles between 1992 and 2016. The Moderate Resolution Imaging Spectroradiometer (MODIS) is an instrument onboard the satellites Terra and Aqua that provides, on average, four images per day and has channels centered at 4 μm and 12 μm that are useful for detecting volcano temperature anomalies. In this work, we evaluated the normalized temperature index (NTI) as implemented by MODVOLC and the radiance recorded by MODIS at 4 μm as measures of precursory volcanic activity between October 2011 and January 2013, with a special focus on the December 2012 eruption. We evaluated the thermal anomalies identified by MODVOLC based on a global threshold of −0.8 and observed that they were namely syn- or post-eruptive and mostly correlated with the presence of incandescence material related to Strombolian activity. The global nighttime threshold was adapted to the local context of Copahue and we observed that a threshold of −0.875 is a more suitable value for the examined period. An analysis of time series of the NTI and of the radiance at 4 μm based on 116 MODIS images, resulted in that the adapted threshold allowed the detection of anomalies undetected by the global value. The anomalies were in either case unrelated to precursory activity but correlated with surface expressions of activity such as the emission of volcanic ash, volcano degassing, and the ejection of ballistic and incandescent material. The knowledge on the chronology of activity prior to and during the eruption could be improved, as regards the thermal behavior of the volcano in relation also to geochemical, deformation, and seismic signals. The replication of this kind of analysis in other periods of activity at Copahue and other volcanoes, the evaluation of other algorithms and the incorporation of data acquired by other satellite instruments are necessary to improve our knowledge on the temperature behavior of volcanoes before and during periods of unrest. This would ultimately contribute towards the improvement of volcano monitoring capabilities in volcanic areas.

Numerical Study of Epoxy-Ramie Fiber Composite as a Type IV Ballistic Resistant Material

This paper studies the response of epoxy-ramie fiber composite as ballistic-resistant material using a finite element model. The simulation test was conducted by varying the number of layers and referred to NIJ 0101.06 Type IV as the boundary condition. The model used was a panel made from epoxy-ramie composite laminates with a certain thickness and a 7.62 mm bullet. NIJ states that ballistic material should withstand penetration, and the back-face signature (BFS) should not exceed 44 mm. The impact energy is not briefly mentioned in NIJ failure criteria. The properties of the composite and the bullet were obtained from scientific literature and previous study. The effect of the number of layers on impact response was evaluated by the penetration, deformation, BFS, and absorbed energy.

CRIMINALISTICS ASPECTS OF THE STUDY BALLISTIC CHARACTERISTICS AND STRIKING PROPERTIES OF BULLETS OF PISTOL CARTRIDGES OF 9 × 21 IMI CALIBER

The article presents data based on the results of experimental studies on the external ballistics parameters and the nature of changes in the trajectory of the kinetic energy of four types of pistol cartridges bullets 9 × 21 IMI (9 × 21 mm.), which were shot from two samples of carbines with different lengths of the rifled part of the barrel. Of particular interest are data on the nature of the shell interaction and expansive bullets of cartridges of the indicated caliber with the tissues of a biological object, the imitation of the interaction with which was carried out using ballistic testing backing material (ballistic clay). The use of a simulator of biological tissues of the human body made it possible to determine the features of the shock-contact interaction of shell and expansive bullets with them, as well as to establish the nature of the behavior of these bullets in the thickness of a viscoelastic medium. It was experimentally found that under certain conditions, 9 mm jacketed bullets are capable of inflicting through wounds to the human body at firing distances up to 25 m inclusive, while the bullet, after breaking through the barrier, has energy characteristics that are sufficient to inflict a penetrating injury of varying severity on another biological object. Due to the use of ballistic clay, it became possible to visualize the maximum amount of damage caused by shell and expansive bullets, as well as to determine the features of the formation of exit wounds, taking into account the destabilization of shell bullets in the thickness of the obstacle. It should be noted that at firing distances up to 5 m inclusive, shell bullets, due to the loss of gyroscopic stability in the tissues of a biological object, which have a sufficiently large thickness, are capable of inflicting wounds, the volume and severity of which are comparable to or exceed the corresponding parameters of wounds caused by expansive bullets. The obtained results of measurements of the velocity of the of shell bullets after overcoming an obstacle in the form of a viscoelastic medium can later become the basis for calculating the contact speed of a bullet with a known length of the channel of the inflicted wound. The article for the first time presents the calculated data on the parameters of the flight path of shell and expansive bullets of pistol cartridges 9 × 21 IMI (9 × 21 mm.) at firing distances up to 100 m. The presented results of experimental studies and calculated data will allow experts in the field of forensic ballistics and forensic medicine to solve the tasks set by the pre-trial investigation authorities. Key words: ballistic clay, biological object, elements of the trajectory of a bullet flight, carbine, pistol cartridge, wound, wound channel, damaging properties, damage.

Post deformation analysis of the ballistic impacted magnesium alloys, a short-review

From the mechanistic point of view, magnesium alloys are lightweight materials and are receiving increasing attention in the past several years in various fields. Prof. Liang Zhen from Harbin Institute of Technology, China and the United State military are showing keen interest in the development of magnesium alloys as ballistic resistant material. However, their use is still limited owing to low ductility, low formability, and average mechanical properties. The magnesium alloys components must withstand the shockwave under hypervelocity ballistic impact. The ballistic testing can produce gradient variations of the strain and stress-energy away from the crater, and useful for the development of these alloys in the military and aerospace industry. Therefore, the present review article shed light on the post deformation analysis of the Mg alloys subjected to the different projectiles under ballistic impact, and the underlying mechanisms were discussed. In the end, some important issues regarding the ballistic impact and further studies in this field were proposed.

FEA of SAW penetration of Ramor 500 steel

Abstract Ramor 500 steel plates are used as a ballistic material due to their greater hardness and strength properties. This steel can be produced with a 2-30 mm thickness sheet which may attain 505-590 HV hardness. In the present work, Ramor 500 steel pairs are joined using a submerged arc welding (SAW) process and taking various parameters into consideration. An austenitic additional wire is used for the welding process which contains Cr, Ni, and Mn. The source model prototype was developed using ANSYS software and considering a time-dependent three dimensional thermal model with source cooling. The highest tensile stress voltage value was determined in the sample applying a constant current of 250 A, 25 V and 30 cm × min-1welding speed. It was observed that the welding seam width increases as welding tension grows and that welding height and depth increase and decrease more or less in tandem. A ANSYS thermal cooling analysis revealed that welding tension grows with heat transfer which increases 15 mm from the main center of the welding area.

FEA of SAW penetration of Ramor 500 steel

Abstract Ramor 500 steel plates are used as a ballistic material due to their greater hardness and strength properties. This steel can be produced with a 2-30 mm thickness sheet which may attain 505-590 HV hardness. In the present work, Ramor 500 steel pairs are joined using a submerged arc welding (SAW) process and taking various parameters into consideration. An austenitic additional wire is used for the welding process which contains Cr, Ni, and Mn. The source model prototype was developed using ANSYS software and considering a time-dependent three dimensional thermal model with source cooling. The highest tensile stress voltage value was determined in the sample applying a constant current of 250 A, 25 V and 30 cm × min-1welding speed. It was observed that the welding seam width increases as welding tension grows and that welding height and depth increase and decrease more or less in tandem. A ANSYS thermal cooling analysis revealed that welding tension grows with heat transfer which increases 15 mm from the main center of the welding area.