Types Of Projectiles Research Articles

Explosive Ordnance Detection in Areas Designated for Mining

Nowadays, mining is becoming increasingly valued, as mines of various types provide a large part of the raw materials needed for construction. In order to ensure a continuous supply of extraction and raw materials, new areas need to be identified and opened up. However, some of these new areas may contain security risks such as explosive remnants of war. If we look back to the events of the World War II, there was perhaps no area in Europe that was not affected by the preparation or execution of some act of war. The warring parties deployed a full arsenal of weapons, some of which still pose a threat today. The various types of bombs, mines, projectiles and grenades were only partially operational. Explosive devices that were simply left behind or unexploded were buried beneath the surface, and continue to pose a growing threat to this day (almost eight decades later). The dismantling and disposal of the left-behind and often very poorly recovered explosive devices has been ongoing ever since. The problems of finding explosive devices and munitions tend to occur in areas where there has been no previous investment, construction or earthworks.

Forensic-radiological diagnosis of gunshot wounds

Although gunshot wounds are less common in Germany than in other countries, aproportion of suicides and violent crimes are committed with firearms, which is why basic knowledge of diagnosis is important. Fundamentals regarding forensic assessment of gunshot wounds are discussed alongside typical radiological findings. In addition to analyzing our own cases and evaluating official statistics, this article is based on adiscussion of basic research and expert recommendations. The article describes the characteristics of the bullet entry and exit as well as special features of the bullet trajectory, particularly in bony injuries, and discusses their significance for radiological findings. Pitfalls in interpretation, such as changes in body position and the deflection of projectile (fragments) in the body, are presented, as are the advantages of supplementary radiological diagnostics (projectile search before initiation of dissection, simple detection of an air embolism, clarity of bullet trajectory reconstruction). This article is intended to provide an overview of not only typical types of weapons and projectiles but also their effects on the body of the victim, which must be documented by the examiner.

Experimental Tests on External and Terminal Ballistics of Different Types of Projectiles Fired From .38 SPL Caliber Cartridges and Study of Permanent Cavitation in Anatomical Modeling With 10% Ballistic Gelatin.

The present study investigated the main morphological differences between the permanent cavities formed by 4 different types of projectiles fired from .38 SPL caliber cartridges in blocks of 10% ballistic gelatin with standardized formulation (Federal Bureau of Investigation Protocol), all fired from the same distance and from the same firearm, associated with its performances in external and terminal ballistics. The velocity or the mass presented by a firearm projectile will not always be solely responsible for the final configuration of the permanent cavity, in which the projectile design, for example, is an equally important element. Each type of projectile tested in the present work generated a different kind of permanent cavity, but they also varied in velocity (m/s) and energy (J). The use of 10% ballistic gelatin in scientific research that seeks to investigate the external and terminal ballistics of projectiles can contribute to the practice of professionals working either in forensic pathology or applied ballistics scenarios, as they can experimentally simulate the events that can occur in the tissues of victims inflicted by gunshot wounds, which also allows important applications in the medical, commercial, civil, and military sectors that deal with products and technologies related to the human body.

Ballistic resistance of 7XXX laminate aluminum alloy plates and base alloys subjected to different projectiles

The ballistic impact of two 7XXX aluminum alloys, 7A52-T6 and 7A62-T6, as well as their combination in a 7B52 laminate plate, was simulated and experimentally tested. Three types of projectiles were utilized hard ogival nosed, hard blunt nosed, and 304 steel core projectiles to investigate the ballistic resistance and failure mechanisms of the aluminum alloy targets. Additionally, an existing modified Gurson-Tvergaard-Needleman (GTN) model incorporating shear, void growth, and spalling failure mechanisms, was employed to simulate the ballistic impact process, utilized to analyze energy dissipation during impact. The results reveal that the 7A52 alloy only experiences ductile hole expansion failure, whereas the 7A62 high-strength aluminum alloy undergoes spalling and fragmentation subsequent to penetration, leading to potential impact hazards. Due to its backing layer being the highly ductile 7A52 alloy, the laminate plate will not produce fragments after penetration. The improved GTN model provided better predictions of the impact failure modes of the aluminum alloys. Concerning impact performance, when subjected to hard ogival projectiles, the laminate alloy did not enhance material impact resistance. However, when impacted by blunt-nosed projectiles, the laminate alloy exhibited a 27 % improvement over the 7A52 plate and an 11.9 % increase over the 7A62 plate. Furthermore, when impacted by 304 steel core ogival projectiles, the laminate alloy demonstrated over a 41.3 % improvement compared to the 7A52 plate and over a 15.5 % increase compared to the 7A62 plate. The laminate plate's high ballistic performance was attributed to the increased plastic deformation energy after spalling failure, while ensuring high energy absorption during ductile hole expansion penetration.

A design model of multi-layer modified aramid fabrics against fragment simulating projectiles and full metal jacketed bullets

Soft body armor is required to meet threats of both bullets and explosion fragments in battlefield. However, designing body armor that can protect against these two types of projectiles considering both critical velocity and back face deformation (BFD) is often based on experience and extensive ballistic experiments. This paper proposes a quick design model for determining the layers of aramid fabrics modified by polyethylene (PE) to protect against fragment simulating projectiles (FSP) and full metal jacketed bullets (FMJ). Firstly, ballistic experiments are conducted discovering the optimal concentration of PE modification against the sphere and FSP is 10 %. Secondly, finite element model is adapted to explore the protection capabilities of modified aramid fabrics against FSP and FMJ and a linear relationship between the BFD and the critical velocity has been observed. Thirdly, an analytical model is established to uncover the reason of this relationship. Finally, a design model is proposed to configure the improved outer tactical vest (IOTV) generation III based on the derived formulae of critical velocity and BFD for different layers of modified aramid fabrics against FSP and FMJ. The model indicates that the objectives of intercepting FSP or FMJ and reducing blunt trauma are usually not simultaneously attainable. 38 layers of modified aramid fabrics are sufficient to meet the protection requirements for both FSP and FMJ, regardless of critical velocity and BFD. Besides, 498 m/s is the threshold of FMJ impact velocity to determine the priority of intercepting bullets or reducing blunt trauma. The design model can serve for the development of lightweight and effective body armor.

Three-dimensional modeling of impact fractures in brittle materials via peridynamics

Accurate prediction of the impact fracture behavior of brittle materials is crucial in various industries. The paper employs the peridynamic method to model the penetration and damage in brittle materials during impact. The proposed three-dimensional peridynamic impact fracture model (3D-PDIFM) overpasses other numerical models by adopting a new computational technique to couple the impact collisions of different types of projectiles with the peridynamic method. Moreover, the 3D-PDIFM is highly efficient in impact fracture simulations by focusing on the effects of the projectile without simulating its particles, thereby saving more computational efforts. Validation through comparison with experimental measurements and observations ensures that the 3D-PDIFM accurately represents the real-world impact fracture behavior of brittle materials. The paper also highlights the efficiency of the 3D-PDIFM in comparison to traditional mesh-based numerical simulations. Therefore, the 3D-PDIFM can be significant for practical engineering applications as efficient simulations can save time and computational resources. Using the validated model, the impact fracture behavior of PMMA under various conditions, such as changes in panel thickness, impact area, and projectile velocity, is investigated. This analysis gains more insights into how these factors affect the brittle material's response to impact. Moreover, the impact fracture behaviors of tempered glass and float glass panels are examined under different conditions of impact loadings. This study also explains the penetration and impact fracture phenomena in brittle materials. Overall, using the 3D-PDIFM as a modeling and simulation tool can help engineers and researchers analyze the behavior of glass panels under various impact scenarios, thus allowing for optimization of design parameters to improve impact resistance.

Projectile seating depth influence on a small arms cartridge performance

In the world of small-arms ammunition, precision reigns supreme. The most significant feature of ammunition for shooters is undoubtedly the repeatability from one shot to the next. This study explores the detailed assembly process of small arms cartridges, leveraging modern machinery and innovative designs employed by cartridge manufacturers. It emphasizes how these tools ensure the fundamental repeatability and precision necessary for the quality of each batch of rounds. Establishing standards for the highest possible quality requires assessing the impact of imprecise cartridge assembly on ballistic performance. Utilizing a free-flight ballistic tunnel, a high-speed camera, light- and target-screen systems, the authors analyzed the effects of varying projectile seating depths thus affecting cartridge overall lengths (COAL) and cartridge base to ogive distance (CBTO) on the initial velocity and bullets’ point of impact at 50 meters. The study was conducted for two types of projectiles, differing in their ogive profiles: secant and tangent ogive. The performance differences between these profiles provided valuable insights for future projectile designs, highlighting that low-drag projectiles are slightly more sensitive to the seating depth than tangent profile bullets, and the importance of it should be considered in mass, military production as well. It is a valuable resource for analyzing the trade-off between producing bullets with a low drag coefficient and ensuring high precision. The research enhances the understanding of internal and external ballistics but most importantly draws attention to the importance of the standards of assembly processes to ensure optimal performance and safety in the field.

First classification of iron meteorite fragment preserved in Chang’e-5 lunar soils

Lunar soil preserves numerous fragments of meteorites impacting on the Moon, providing a unique opportunity to investigate the distribution of the types of projectiles over billions of years. Here we report the first discovery of an iron meteorite fragment from the Chang’e-5 lunar soil, which consists mainly of martensite (quenched from taenite), kamacite, and schreibersite, with a trace of pentlandite. The meteorite fragment is Ni- and P-rich, S-poor, and based on its mineral chemistry and bulk composition, can be classified into the IID-group, a rare and carbonaceous group of iron meteorite originating in the outer Solar System. This meteorite fragment experienced only limited partial melting followed by fast cooling, suggestive of efficient preservation of intact remnants of iron meteorites impacting on the porous lunar regolith. Alternatively, it is a relic of a low-velocity impact of submillimeter-sized metal grains originated from an IID-like iron meteorite. Our observations demonstrate that it is feasible to achieve the type distribution of meteorites impacting on the Moon via systematically analyzing a large number of metal grains separated from lunar soils, thus shedding light on the dynamic evolution of the Solar System.

Ballistic perforation of aramid laminates: Projectile nose shape sensitivity

The influence of projectile shape on the ballistic properties and mechanism of aramid laminates is investigated through experiments and simulations. Three types of projectiles (blunt, hemispherical, and ogival) are used to obtain ballistic curves. The dynamic penetration process, deformation and damage characteristics of the targets are analyzed. A three-dimensional finite element model is established, and good agreement is observed between the simulation and test results. The findings demonstrate that projectile shape significantly impacts the ballistic response of aramid laminates. As the projectile transitions from blunt and hemispherical to ogival, the ballistic limiting velocity decreases continuously, the area of target plate deformation and damage decreases, and the occurrence of delamination becomes less pronounced. And the energy dissipation through local damage, elastic deformation and overall motion of the aramid material is decreasing and the energy dissipation through friction is increasing.

Performance of Carbon Fiber-Reinforced Polymer Plates Against Impact Loading

The carbon-fiber laminated composites are widely used in various industrial sectors due to their magnificent mechanical and engineering properties. While designing the structures of strategic importance, the impact perforation study and prediction of impact performance of such composites are of utmost importance. This work basically concentrates on two major areas of impact perforation study, determining impact perforation characteristics and understanding the perforation process. The objective has been achieved through experimental as well as numerical investigations. Microstructural analysis have also been carried out to understand different energy-absorbing mechanisms. The pneumatic gun setup is utilized to fire the projectile. In addition, square-shaped carbon fiber laminates and projectiles are modeled in ABAQUS/Explicit. The carbon fiber laminates of different thicknesses and layup sequences are impacted with three different types of projectiles. The cross ply, angle ply and quasi-isotropic layup sequences are considered in this study. The conical, blunt and ogive nose with caliber radius head (CRH) 1.5 projectiles are modeled as analytical rigid. Hashin criteria are adopted to replicate the behavior of carbon fiber laminates. The experimental and numerical calculations are compared and are found to be in good agreement. The different perforation features are calculated and the influence of ply orientations, thickness, projectile shape and impact velocities on the performance of targets against impact are discussed. An efficient and better laminate configuration under various ballistic conditions has been sought.

Electronic cross section, stopping power and energy-loss straggling of metals for swift protons, alpha particles and electrons

Understanding and quantifying the electronic inelastic interactions of swift ions and electrons in metals is fundamental for many applications of charged particle beams. A common theoretical approach is moreover desirable for the case of both types of projectiles, as large numbers of secondary electrons arise as the result of ion interaction with metals. The electronic cross section, stopping power and energy-loss straggling resulting from the interaction of swift protons, alpha particles and electrons when moving through the metals aluminum, iron, copper, molybdenum, platinum and gold, are calculated theoretically for a wide energy range of the projectiles. The model is based on the dielectric formalism, which realistically accounts for the excitation spectrum of each metal through the Mermin Energy-Loss Function–Generalized Oscillator Strength (MELF-GOS) methodology. The impact of the complexity of the excitation spectrum of each metal (encompassing interband transitions and collective excitations), as well as the different sources of (sometimes conflicting) optical data is analysed in detail. Specific interactions are considered for each projectile, such as electron capture/loss and electron cloud polarisation for ions, and indistinguishability, exchange and low-energy corrections for electrons. An estimate of possible contributions of surface excitations to the interaction probabilities of low energy electrons is given. Comparison of our results with a large collection of available experimental data shows good agreement. As a practical and useful outcome of the work, we provide analytical expressions fitting all our calculated quantities, which can be applied for simulation or comparison purposes.

Methods of calculation and engineering protection of critical infrastructure objects and other strategic facilities against long-range projectiles

Relevance. One of the key areas of russia's military operations against Ukraine is the destruction of critical infrastructure objects (CIO) of strategic importance. The main types of enemy means for air strikes on CIO are air-launched, ground-launched and water-launched missiles, as well as barrage munitions. The vast majority of the CIO were built in Ukraine above ground, without any engineering structural protection systems to counter air threats, explosions or other impacts related to military operations. The importance of developing the most effective methods of engineering structural protection of the CIO from various types of projectiles as soon as possible was demonstrated by the experience of Ukraine's war with russia, in particular, the analysis of the significant impact of damage to the CIO in the energy sector. At present, Ukraine has a certain lack of regulatory data for designing reliable protective structures for CIO. The aim of this work is to develop a regulatory base for making calculations for the possible impact of various types of forceful effects from air strikes, terrorist attacks, etc. when designing the CIO and other strategic facilities. Currently, the issue of organising the defence of critical infrastructure and other strategic objects is being systematically addressed on the basis of the "Country-Fortress" principle, which provides for the organisation of echeloned air defence combined with comprehensive civil and engineering defence measures. In addition, it is necessary to provide for the reliable protection of existing facilities, taking into account the hazards and threats of today. The process of reducing the risks of damage to the CIO involves identifying threats, their comprehensive assessment, developing measures to reduce threats and their prompt implementation, followed by an assessment of the measures effectiveness. Results. The presented methods of risk assessment of critical infrastructure damage, methods of their engineering and analytical calculations and methods of engineering structural protection against ammunition of various types allow developing an effective integrated system of protection of strategically important objects. The article deals with both the protection of existing facilities and the design of new ones, taking into account the requirements for engineering protection and civil defence.

Studying the ballistic performance of a metal target under combined KE projectile impact

In this article, using analytical, numerical and experimental methods, the range of the ballistic limit thickness (BLT) of the metal target in the impact with the combined kinematic energy (KE) projectile is investigated. The design of these types of projectiles is to achieve effective damage behind the target and they consist of two components that are coaxial and back to back. The first KE projectile (FKEP) is a filled cylinder and acts as a leading projectile, while the second KE projectile (SKEP) is a hollow cylinder carrying a fuse and explosive materials and causing damage (behind the target) is obtained by the complete passage of this projectile from the target. There is little research available in the field of penetration analysis of these projectiles, and only a semi-analytical model based on shock theory has been presented for the analysis of hollow cylindrical projectile penetration. In this research, using the shock theory, a new analytical model is presented to predict the performance of the combined KE projectile in the metal target. In parallel, experimental tests of combined KE projectile hitting a metal target (using a Gas Gun weapon) and also a 2D axisymmetric simulation (LS Dyna software) were performed in the range of 200–850 m s−1 impact velocity. The average difference between the results of experimental tests and numerical simulation with the results of the analytical model is 7 and 5% respectively.

Ballistic Behavior of Bioinspired Nacre-like Composites.

In this paper, the ballistic performance of a multilayered composite inspired by the structural characteristics of nacre is numerically investigated using finite element (FE) simulations. Nacre is a natural composite material found in the shells of some marine mollusks, which has remarkable toughness due to its hierarchical layered structure. The bioinspired nacre-like composites investigated here were made of five wavy aluminum alloy 7075-T651 (AA7075) layers composed of ~1.1-mm thick square tablets bonded together with toughened epoxy resin. Two composite configurations with continuous layers (either wavy or flat) were also studied. The ballistic performance of the composite plates was compared to that of a bulk monolithic AA7075 plate. The ballistic impact was simulated in the 300-600 m/s range using two types of spherical projectiles, i.e., rigid and elastoplastic. The results showed that the nacre plate exhibited improved ballistic performance compared to the bulk plate and the plates with continuous layers. The structural design of the nacre plate improved the ballistic performance by producing a more ductile failure and enabling localized energy absorption via the plastic deformation of the tablets and the globalized energy dissipation due to interface debonding and friction. All the plate configurations exhibited a better ballistic performance when impacted by an elastoplastic projectile compared to a rigid one, which is explained by the projectile plastic deformation absorbing some of the impact energy and the enlarged contact area between the projectile and the plates producing more energy absorption by the plates.

Ballistic performance of additive manufacturing 316l stainless steel projectiles based on topology optimization method

Material and structure made by additive manufacturing (AM) have received much attention lately due to their flexibility and ability to customize complex structures. This study first implements multiple objective topology optimization simulations based on a projectile perforation model, and a new topologic projectile is obtained. Then two types of 316L stainless steel projectiles (the solid and the topology) are printed in a selective laser melt (SLM) machine to evaluate the penetration performance of the projectiles by the ballistic test. The experiment results show that the dimensionless specific kinetic energy value of topologic projectiles is higher than that of solid projectiles, indicating the better penetration ability of the topologic projectiles. Finally, microscopic studies (scanning electron microscope and X-ray micro-CT) are performed on the remaining projectiles to investigate the failure mechanism of the internal structure of the topologic projectiles. An explicit dynamics simulation was also performed, and the failure locations of the residual topologic projectiles were in good agreement with the experimental results, which can better guide the design of new projectiles combining AM and topology optimization in the future.

Study of the effects of projectile strength and density in the asteroid deflection by hypervelocity impact

In recent years, potentially hazardous asteroids (PHAs), which have orbits approaching the Earth and are a threat to humankind, have been attracting attention. It is necessary to prevent them from impacting the Earth, and asteroid deflection by hypervelocity impact is one of the best impact avoidance. This asteroid deflection needs to be greater, but momentum enhancement factor β, which represents deflection efficiency, is affected by various factors. This study focused on projectile strength and density, and experiments for small-scale impacts and numerical simulations for large-scale impacts were conducted to clarify these effects on β. In experiments, six types of projectiles with different strengths and densities and the same shape and size were impacted into brick targets at 1-3.5 km/s using a Two-Stage Light Gas Gun to investigate the effects in actual impacts. In simulations, three types of projectiles with different densities and the same shape and mass were impacted into granite targets at 3-10 km/s using AUTODTN to investigate the effects in asteroid-deflection-scale impacts, which are difficult for experiments. In conclusion, the effect of projectile strength on β is less, and the one of projectile density on β is high. It is demonstrated that projectiles whose density is close to the target density increase β, namely, are suitable for asteroid deflection regardless of impact scale. Additionally, a crater formed by hypervelocity impact is a preferably flat shape for asteroid deflection, and the effect of crater shape on β is higher at large-scale impact. Further study of this effect and the scaling one could be expected.

Failure analysis through fragmentation behaviour of Al 2024 alloy subjected to high strain Rates- experimental and numerical studies

The failure mechanisms through fragmentation and their effect on the Al2024 alloy and its temper condition when subjected to high strain rates experienced in aerospace and defence applications are scarce in the literature. The present work deals with the investigation of as-received Al2024- T3 and its temper condition Al2024-T3 + T6 subjected to the ballistic impact on single stage gun in the velocity range of 50–250 m/s for their deformation behaviour. Three types of nose-shaped projectiles- blunt, hemispherical and ogive were triggered onto 3 mm target plates in the normal direction. The difficulty in retrieving the fragments during the experimental investigations motivated the perception of the numerical analyses. Two approaches such as the Conventional Erosion Model (CEM) and Node Separation Model (NSM) on LS DYNA software were developed and adopted. The residual velocities, Ballistic Limit Velocities (BLV), Kinetic Energy Absorption (KEA) and their deformation mechanisms were compared and analysed for the two target alloy conditions to obtain better ballistic-resistant material. Ogive projectile has shown to be the best penetrator for the alloy materials and additionally, the KEA for the tempered condition was higher compared to the Al2024-T3 and Al2024-T3 + T6 just above the BLV. The NSM methodology for fragmentation analysis has been proved to be a promising technique and the estimates were comparable and realistic to those of experimentally obtained estimates.

Modeling and ballistic tests of selected soft point projectiles in a water medium

Methods used nowadays in forensic laboratories allow to stop some kinds of projectiles with degree of deformation which lets to use them for comparing traces to projectiles found on the crime scene. However they are not useful for every type of projectiles. Comparative physical tests are enough to indicate the best method for soft catching projectiles. For this aim point of view no modeling needed. The paper presents the results of ballistic tests of impact of chosen types of soft point projectiles into water. The behavior of projectiles of various shapes, with different kinetic energy, was analyzed. On the basis of the obtained results, the projectiles with the highest susceptibility to deformation were identified. Research works described in the paper were performed within the framework of the project Laboratory stand for stopping high-energy projectiles financed from the National Centre for Research and Development (Agreement no. DOB-BIO10/04/02/ 2019). The project is implemented in cooperation with Warsaw University of Technology, Military Institute of Armament Technology and Tebbex 2 since 2019 to 2022.

The false nose shape in a high velocity projectile penetration into dry sand

The present article deals with a particularly interesting phenomenon of a false nose that is formed during the high velocity penetration of a projectile into a granular soil like sand. The false nose is composed of compacted, fractured, and comminuted sand particles. It is formed as a cap in front of flat nose projectile and accompanies the projectile during its penetration. Only limited sparse experimental evidence exists on the false nose shape that is mostly observed after the penetration event. So far, no theoretical study was carried out to assess the false nose shape and its effect on penetration. The present paper conjectures that the shape of the false nose is equal to the optimal shape formed from the target soil material that yields the minimal resistance during its penetration in the soil. This nose together with the original flat nose projectile behind, yield a stable deep penetration that is comparable to projectiles with shaped noses. The present study extends the approach of a full false nose in front of a flat nose projectile, to a partially added false nose in front of a hemispherical, spherical, or other short noses. Analysis of experimental images of false noses verifies the above conjecture and prove that the shape of the false nose is very close to the optimal shape of a projectile nose that is made of compacted soil. These findings enable implementation of the well-proven DISCS approach (which was originally developed for penetration of projectiles with slender noses into various compressible media) and extend it for flat, spherical and hemispherical projectiles penetration into a granular soil. The efficiency of the proposed approach is demonstrated through numerous examples for the above types of projectiles, at various impact velocities, showing very good agreement with experimental data.

Research on the Dynamic Response Properties of Nonlethal Projectiles for Injury Risk Assessment.

Based on the models already on the market, we have manufactured six types of nonlethal projectiles. We have made convex heads out of polyurethane foam (PUR) filled with mineral fillers like alumina (Al2O3) and montmorillonite (MMT). We chose a suitable holder for nonlethal projectiles. Also, we made a custom industrial model and used CAD modeling in SolidWorks to simulate the deformation of the nonlethal projectiles. The polymeric nonlethal projectile holders were then 3D-printed. We performed a dynamic mechanical analysis (DMA) and discussed the results. Likewise, we conducted ballistic impact experiments on nonlethal projectiles (XM1006) and nonlethal projectiles manufactured that were evaluated using a rigid wall and a pneumatic launcher. Furthermore, we looked at cell structure, the spread of the mean pore diameter, and the particle size distributions of the mineral fillers using scanning electron microscopy (SEM). We evaluated and discussed injury risks from nonlethal impacts. Data on nonlethal projectile lethality and safe impact speed are collected. This study explains how lab studies and real-world practice coexist through nonlethal projectile properties.