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User expects his weapon to be light and reliable and to perform multiple times firing per unit time at the same time. In today's technology, the maximum number of firings can be made per unit time with steel barreled weapons, but in composite barrels; many problems occur due to overheating, strength and reliability. Meeting these opposite demands is an engineering problem. In this study, the design of a composite‐steel combination light gun barrel is studied. Firstly, pressure distribution through the barrel has been calculated using Vallier‐Heydenreich method. According to the calculations, analysis has been conducted using both steel barrel and composite barrel. After the analysis, a composite barrel has been manufactured and testing has been conducted on an all‐steel barrel and the manufactured composite barrel. Composite is carbon fiber and resin is epoxy resin. In composite material, carbon fiber is preferred at the rates of 50% and 60%, the material of the steel barrel is AISI 416R stainless steel. The manufactured steel barrels have the same outer diameter but different wall thickness ratios, firing tests were conducted in such a way that the number of shots per unit time was the same. Highlights: Stress distribution within a gun barrel was calculated using Vallier‐Heydenreich method.Design and finite element analysis analysis for an all‐steel gun barrel and a composite gun barrel was conducted.A composite gun barrel was manufactured; by using composite materials, the barrel was lightened by 24.8%.The manufactured composite gun barrel and an all‐steel gun barrel were tested by firing over 2500 shots. [ABSTRACT FROM AUTHOR]

Background: Plastic Surgery originated in war and still has an important role in the management of war wounds and their sequelae. Since June 2022 the Plastic Surgery department of Zaragoza's Miguel Servet University Hospital has been involved in the management of patients with injuries secondary to the Russo-Ukrainian War. In this paper we describe the activity of the plastic surgeons involved and the types of injuries and procedures performed. Methods: We included patients injured in the Russo-Ukrainian conflict transferred for multidisciplinary care to the General Defence Hospital in Zaragoza from June 2022 until December 2023. We gathered epidemiological data, mechanism of injury, anatomical location, types of plastic surgery performed, number of interventions and complications. Results: In the period from June 2022 to December 2023 the multidisciplinary team provided care for a total of 59 patients. Plastic surgeons were involved in the care of 16 patients with a total of 34 plastic surgery procedures: 7 microsurgical free flaps, 6 regional flaps, 4 grafts, 8 debridements, 3 flap remodelings, 4 Targeted Muscle Reinervations, 1 amputation and 1 hand surgery. Three patients suffered from major complications in the form of infections of the surgical wound. Conclusions: Our study showed the crucial role of Plastic Surgery in the management of war injuries and the high proportion of high-complexity microsurgical procedures needed to take care of this type of injury. Level of evidence: Level IV, Therapeutic. [ABSTRACT FROM AUTHOR]

The use of ordnance gelatine has been widespread in the field of ballistics as a simulant for soft tissue when assessing ballistic threats. However, the traditional method of preparing ordnance gelatine is time-consuming and requires precision to ensure that the final mold meets the required specifications. Furthermore, temperature control is necessary post-production, and there are limitations on its usage duration. To address these issues, manufacturers have developed pre-mixed, gelatine-like products that are stable at room temperature and require less preparation time. Nonetheless, it is uncertain whether these new products can perform in the same manner as the gold standard of ordnance gelatine. This study used five types of blocks, including ordnance gelatine (10% and 20%), Clear Ballistics (10% and 20%) and Perma-Gel (10%) and subjected them to 9 mm, 0.380 Auto fired from a universal receiver and a 5.56 × 45 mm ammunition fired by a certified firearms instructor. Delta-V and total energy dissipation were measured after each test using data collected from ballistic chronographs placed in front of and behind each block. High-speed video was recorded, and a cut-down analysis conducted. The findings revealed variations in energy dissipation and fissure formation within the block, with greater energy based on fissure formation observed in the ordnance gelatine. Additionally, the high-speed video showed the occurrence of secondary combustions occurring in the premixed gelatines. [ABSTRACT FROM AUTHOR]

The possibility of enhancing the ballistic performance of aramid fabrics such as Kevlar through the impregnation of nanoparticles is well established. In this study, the influence of the nanoparticle's specifications such as size, shape, and material on the underlying mechanisms is investigated. A colloid-based treatment process is used to impregnate dry nanoparticles into Kevlar fabric. Using a customized gas gun rig, neat and treated samples are tested to determine the kinetic energy absorbed. Silica, alumina, and zinc oxide nanoparticles ranging from 10 to 125 nm, with spherical or cylindrical shape are considered. Silica treated samples perform significantly better (83% increase in energy absorbed vs neat fabric) than alumina or zinc oxide treated samples, likely due to greater agglomeration between yarn interfaces leading to enhanced frictional mechanisms. The exit-face damaged zone area acts as a surrogate for energy absorbed as it correlates well across all samples. Compared to samples with three layers treated individually, samples with three layers treated together display a 21% enhancement in the energy absorbed. Specific energy absorbed for three layers treated together with 80-nm silica is nearly 3 times higher than that for the neat fabric. Samples with three layers treated together with 80-nm silica provide the same performance as the neat fabric for a projectile that is nearly 70 m/s faster. Hybrid structural materials such as nanoparticle-fabric composites offer a promising route to enhance ballistic performance without weight penalty, while being amenable to multifunctional applications. [ABSTRACT FROM AUTHOR]

Study of the engraving process is significant for interior ballistics. Due to the high transient and strong nonlinear characteristics of the engraving, research on the engraving mechanism is challenging. In this paper, based on the one-dimensional two-phase flow model of interior ballistics coupled with explicit dynamics software, finite element simulation of the engraving is carried out to obtain the changes of parameters during the engraving process, and the dynamic characteristics of the projectile engraving are discussed. By comparing the simulation results with the experimental data, the accuracy of the coupling method in this paper is verified. The relationship between the structural parameters of the sealing band and the extrusion resistance is revealed, and the influence of the extrusion resistance on the dynamic characteristics of the projectile is demonstrated. The simulation results can provide an essential reference for selecting a reasonable sealing band structure. [ABSTRACT FROM AUTHOR]

Background: Use of ultrasound (US) for procedural needle guidance can improve success rates, safety, and accuracy. Often, training is performed on task trainers, which can be prohibitively expensive. Determining undesired needle placement is difficult when the needle is poorly visualized with US. Currently available simulation phantoms cannot provide real‐time feedback on the location of needle placement. Objectives: The primary objective was to develop and determine feasibility of a low‐cost simulation phantom with an internal circuit and LED light system to determine when a needle contacts internal structures. We also aimed to determine whether its use was associated with increased comfort level. Methods: Emergency medicine (EM) residents (PGY‐1 to PGY‐3) performed in‐plane and out‐of‐plane US needle guidance using homemade phantoms. Comfort levels were assessed by pre‐ and post intervention survey. Outcomes were measured on Likert scale (minimum = 1, maximum = 5). The primary outcome was change in confidence markers before and after the simulation task. Secondary outcomes were survey results of comparisons of these models to prior training experiences on simulators and humans. Results: All EM residents (30) in our program were invited to participate. Twenty participants enrolled and completed the study. In the primary outcome, median comfort with out‐of‐plane and in‐plane guidance increased after using the model but was more pronounced for out‐of‐plane guidance. On a posttest survey, residents rated the models overall very similar to prior experience on simulators (median 5/5 [IQR 4.0–5.0]) and moderately similar to humans (median 3/5 [IQR 3.0–4.0]). Conclusions: We created a low‐cost ballistic gelatin phantom with an internal electric needle guidance system. Use of the phantom for training was associated with increased learner comfort with the procedure. Learners rated the characteristics of the phantom as similar to higher‐cost commercial equipment and humans. [ABSTRACT FROM AUTHOR]

Sprinkler irrigation is widely used in agriculture because it allows for rational use of water. However, it can induce negative effects of soil erosion and of surface waterproofing. The scholars of these phenomena use the numerical integration of the equation of motion, but if there was an analytical solution, the study would be facilitated, and this solution could be used as software for regulating sprinklers. Therefore, in this study, the solution of the differential equation of the flight of droplets produced by sprinklers in the absence of wind was developed. The impossibility of an exact analytical solution to the ballistic problem due to the variability of the drag coefficient of the droplets is known; therefore, to find the integrals in closed form, the following were adopted: a new formula for the drag coefficient; a projection of the dynamic's equation onto two local axes, one tangent and one normal to the trajectory and some linearization. To reduce the errors caused by the latter, the linearization coefficients and their calculation formulas were introduced through multiple non-linear regressions with respect to the jet angle and the initial droplet speed. The analytical modeling obtained, valid for jet angles from 10° to 40°, was compared to the exact numerical solution, showing, for the total travel distance, a high accuracy with a mean relative error MRE of 1.8% ± 1.4%. Even the comparison with the experimental data showed high accuracy with an MRE of 2.5% ±1.1%. These results make the analytical modeling capable of reliably calculating the travel distance, the flight time, the maximum trajectory height, the final fall angle and the ground impact speed. Since the proposed analytical modeling uses only elementary functions, it can be implemented in PLC programmable logic controllers, which could be useful for controlling water waste and erosive effects on the soil during sprinkler irrigation. [ABSTRACT FROM AUTHOR]

A set of non-linear optimisation algorithms are combined with a finite element simulation code to analyse the energy absorption and elastic stress wave propagation problem in multilayer/multimaterial armour systems under ballistic impacts. An Abaqus Python script is used to simulate the ballistic event and to generate the variables and post-processing outputs necessary for the integration with the optimisation algorithms. A number of modelling strategies are considered and three optimisation algorithms are used: Particle Swarm Optimisation (PSO), Genetic Algorithm (GA) and Simulated Annealing (SA). The performance and efficiency of each algorithm are assessed through four benchmark tests with different levels of complexity. A multi-objective optimisation procedure is proposed that uses the most efficient algorithm based on every single-objective formulation, variables and constraints from the benchmark tests, resulting in a highly non-linear problem. The proposed optimisation methods successfully achieve the study purposes both in the simulation of generic ballistic impacts and in the quality of the optimised solutions, demonstrating the potential for this type of optimisation method on terminal ballistic applications, serving as a standpoint for further studies into higher energy impacts and material non-linearities. [ABSTRACT FROM AUTHOR]

The large compositional space of high entropy alloys (HEA) often presents significant challenges in comprehensively deducing the critical influence of atomic composition on their mechanical responses. We propose an efficient nonparametric kernel-based probabilistic computational mapping to obtain the optimal composition of HEAs under ballistic conditions by exploiting the emerging capabilities of machine learning (ML) coupled with molecular-level simulations. Compared to conventional ML models, the present Gaussian approach is a Bayesian paradigm that can have several advantages, including small training datasets concerning computationally intensive simulations and the ability to provide uncertainty measurements of molecular dynamics simulations therein. The data-driven analysis reveals that a lower concentration of Ni with a higher concentration of Al leads to higher dissipation of kinetic energy and lower residual velocity, but with higher penetration depth of the projectile. To deal with such conflicting computationally intensive functional objectives, the ML-based simulation framework is further extended in conjunction with multi-objective genetic algorithm for identifying the critical elemental compositions to enhance kinetic energy dissipation with minimal penetration depth and residual velocity of the projectile simultaneously. The computational framework proposed here is generic in nature, and it can be extended to other HEAs with a range of non-aligned multi-physical property demands. [ABSTRACT FROM AUTHOR]

Gunshot wound analysis is an important part of medicolegal practice, in both autopsies and examinations of living persons. Well-established and studied simulants exist that exhibit both physical and biomechanical properties of soft-tissues and bones. Current research literature on ballistic wounds focuses on the biomechanical properties of skin simulants. In our extensive experimental study, we tested numerous synthetic and natural materials, regarding their macromorphological bullet impact characteristics, and compared these data with those from real bullet injuries gathered from medicolegal practice. Over thirty varieties of potential skin simulants were shot perpendicularly, and at 45°, at a distance of 10 m and 0.3 m, using full metal jacket (FMJ) projectiles (9 × 19 mm Luger). Simulants included ballistic gelatine at various concentrations, dental silicones with several degrees of hardness, alginates, latex, chamois leather, suture trainers for medical training purposes and various material compound models. In addition to complying to the general requirements for a synthetic simulant, results obtained from dental silicones shore hardness 70 (backed with 20 % by mass gelatine), were especially highly comparable to gunshot entry wounds in skin from real cases. Based on these results, particularly focusing on the macroscopically detectable criteria, we can strongly recommend dental silicone shore hardness 70 as a skin simulant for wound ballistics examinations. [ABSTRACT FROM AUTHOR]

Contact shots to the head often leave behind biological traces inside firearm barrels, a phenomenon of great forensic interest. Until now, the visualization and preservation of these traces presented a significant challenge, lacking a reliable method. This study addresses this gap by searching for a suitable method to extract the traces within a casting. Using alginate or gelatine as suitable materials, the results were hampered by serious adhesion issues and their extraction out of the firearm barrel was impeded. Finally, the combination of 11% gelatine with 1% alginate, introduced into the barrel around a 'central spine', succeeded to consistently produce replicable castings. Experimental contact shots displayed a distinct staining gradient from the muzzle to the rear of the barrel, as revealed through endoscopy and proved in the macroscopic casting. The technique proved effective for various common handgun barrels and successfully preserved blood and gunshot residue (GSR) patterns within the barrel. This method offers the dual benefits of visually mapping staining patterns and securing localized samples for targeted molecular genetic analysis in forensic investigations. [ABSTRACT FROM AUTHOR]

We present here the fabrication at the wafer level and the electrical performance of two types of graphene diodes: ballistic trapezoidal-shaped graphene diodes and lateral tunneling graphene diodes. In the case of the ballistic trapezoidal-shaped graphene diode, we observe a large DC current of 200 µA at a DC bias voltage of ±2 V and a large voltage responsivity of 2000 v/w, while in the case of the lateral tunneling graphene diodes, we obtain a DC current of 1.5 mA at a DC bias voltage of ±2 V, with a voltage responsivity of 3000 v/w. An extended analysis of the defects produced during the fabrication process and their influences on the graphene diode performance is also presented. [ABSTRACT FROM AUTHOR]

Functionally graded materials (FGMs) with a gradual transition from ceramic to metal are believed to have superior ballistic performance compared to ceramic/metal composite armors. Therefore, multilayered SiC/AA7075 FGM samples of size 50 × 50 mm are synthesized using a relatively simple and inexpensive technique, i.e., powder metallurgy. The armor requirements depend upon the type of threat and hence, the region and circumstances. Therefore, unlike most of the available investigations, the present study deals with FGM armors with low areal density (< 30 kg/m2) against 7.62 × 39 mm Hardened Steel Core bullets. Two different FGM designs comprising 3 and 5 layers of SiC/AA7075 composite, with 10-30-50 wt.% SiC and 10-20-30-40-50 wt.% SiC, respectively, are developed herein along with a homogeneous composite with 30 wt.% SiC for comparison. The fabrication process involves the stacking of powder blends pertaining to different layers in the die cavity followed by hot pressing at a temperature of 400 °C and 325 MPa pressure. The green compacts are then subjected to pressureless sintering at 540 °C for 3 h. Solution heat treatment and aging are found to enhance the hardness of each layer significantly. The results of the depth of penetration-based ballistic evaluation profoundly establish the superiority of FGM armors over homogeneous composites. Besides, a one-dimensional stress wave propagation-based analysis is also presented herein to explain the reason for the better ballistic performance of FGMs. [ABSTRACT FROM AUTHOR]

To enhance the comprehensive performance of artillery internal ballistics--encompassing power, accuracy, and service life--this study proposed a multi-stage multidisciplinary design optimization (MS-MDO) method. First, the comprehensive artillery internal ballistic dynamics (AIBD) model, based on propellant combustion, rotation band engraving, projectile axial motion, and rifling wear models, was established and validated. This model was systematically decomposed into subsystems from a system engineering perspective. The study then detailed the MS-MDO methodology, which included Stage I (MDO stage) employing an improved collaborative optimization method for consistent design variables, and Stage II (Performance Optimization) focusing on the independent optimization of local design variables and performance metrics. The methodology was applied to the AIBD problem. Results demonstrated that the MS-MDO method in Stage I effectively reduced iteration and evaluation counts, thereby accelerating system-level convergence. Meanwhile, Stage II optimization markedly enhanced overall performance. These comprehensive evaluation results affirmed the effectiveness of the MS-MDO method. [ABSTRACT FROM AUTHOR]

Purpose. Solution of the three-dimensional nonlinear problem of external ballistics and development of an approximate mathematical model of the dynamic process for cargo falling from low-speed aircraft, which makes it possible to obtain an analytical solution, which is possible in combination with a geometric representation of the dynamic process using computer algebra. Methodology. Utilizing a blend of analytical and numerical research algorithms, an innovative model was devised, grounded in a nonlinear system of differential equations characterized by time-varying coefficients. The applied three-dimensional approach to the dynamic problem with an initial velocity from a UAV, in the presence of frontal and side wind loading, made it possible to use the nonlinear theory of external ballistics. This streamlining of the problem involved solving a related system of differential equations with variable coefficients along corresponding coordinates, leveraging an asymptotic approach. Furthermore, the formulation of the problem incorporated applied mathematical analysis and modeling, accommodating various pertinent environmental parameters. Findings. The creation of mathematical models and algorithms for calculating the parameters of the dynamic process of falling loads from low-speed aircraft within the framework of the theory of nonlinear external ballistics is an urgent problem both from the point of view of the development of the dynamic theory of the specified class of systems, and the creation of effective calculation algorithms with the possibility of practical application. As a result of the research, characteristic valuations of the influence of variable coefficients on the results of estimated accuracy of landing as a derivative of time were obtained. The obtained analytical and graphical dependences with the provision of appropriate assessments of the applied approach make it possible to establish the correlation of methods and results. Originality. The relevance of scientific research in the field of nonlinear external ballistics is based both on the internal trends of the development of this science and on the urgent needs of modern industry. In this paper, an approximate analytical solution of the nonlinear problem of external ballistics is proposed, which is subject to the applied conditions of motion. The resulting dependencies made it possible to establish the relationship between the parameters and find the degree of their influence on the landing time function. Practical value. The derived analytical findings and solution methodology can be integrated into practical applications within the realms of mathematical physics and engineering computations. This is particularly pertinent in the advancement of control algorithms for ballistic systems. [ABSTRACT FROM AUTHOR]

The analysis was performed on six commonly used 5.56 x 45 mm projectile types (M193, M855, M855A1, L31A1, M995, and AP45). The projectile's impact velocity (chosen as 900 m/s) was the same in the examination process. This made it possible to assess how the projectile's design has affected its performance against a hard steel target. These evaluations included numerical simulations (Ansys Autodyn) of projectile impacts. Using the available experimental data, the materials in the computational model were first validated. A short description and CAD model of projectiles is also given. Relevant conclusions were reported. [ABSTRACT FROM AUTHOR]

Although underwater submerged launching has been rigorously investigated for decades, there remains a dearth of comprehensive understanding regarding the underwater interior ballistic characteristics for varying barrel lengths. To address this knowledge gap, the present study aims to explore, via numerical simulations, the initial velocity of interior ballistics, projectile drag, and the mechanism of initial flow field formation at the muzzle under various barrel lengths, thereby considering the influence of differing barrel lengths. The five distinct lengths of barrels are expressed as dimensionless ratios of the weight of water column in front of the projectile to the weight of the projectile in order to be more general. Five different ratios of water-to-projectile weight are investigated: 1.0, 1.2, 1.5, 1.8, and 2.0, all possessing identical diameters and evaluated under equivalent launch conditions. Different ratios significantly impact muzzle velocity, with shorter barrels yielding higher muzzle velocities, while ensuring complete propellant combustion. Further investigations indicate that variations in drag constitute the fundamental cause of initial velocity changes. Furthermore, it is observed that barrels of different lengths exhibit identical characteristics at the point of maximum drag. The initial flow field at the muzzle exhibits considerable variations in terms of length, profile dimensions, and intensity. The findings of this study offer valuable insights into exploring the mechanism of submerged launching and will be utilized to investigate the optimal barrel length. [ABSTRACT FROM AUTHOR]

During engineering blasting operations, various man-made elements (particles) can be formed from the structure due to the impact of an explosion, which, as experimental data show, can have a completely arbitrary shape and a fairly large mass and speed. This article is devoted to consideration of the ballistics of elongated elements and the derivation of the calculated dependencies that allow one to estimate the trajectory of their movement. [ABSTRACT FROM AUTHOR]

In this study, the ballistic resistance of SiC (silicon carbide) and a SiC mixture S80B20 (80% SiC/20% B4C) backed with UHMWPE (ultra-high-molecular-weight-polyethylene) fiber board was investigated by striking it with a.30-06 armor piercing projectile. The front plate of the high hardness ceramics is intended to passivate the bullet and limit the bullet's impact kinetic energy, and the high strength backing plate undergoes plastic deformation, absorbing the bullet's residual energy. Ballistic tests revealed that an 8 mm thick S80B20 ceramics produced at a sintering temperature of 2120° or 2140°C, combined with a composite plate, can successfully resist.30-06 armorpiercing rounds with energy greater than 3900 J. The optimal SiC plate meeting the NIJ 0101.06 Level IV was an 8 mm thick SiC sheet backed with 9 mm of fiber board (total thickness, 17 mm; areal density, 33.217 g/m2). The 8 mm thick 80% SiC/20% B4C plate sintered at 2120°C, backed with 7 mm fiber board, had an areal density of only 29.615 kg/m2. If the depth of penetration is less than 44 mm, the fiber board thickness must be increased from 7 to 8 mm, increasing the areal density to 30.552 kg/m2. Compared with the SiC ballistic plate, the density of the composite is 2.665 kg/m2 lower. [ABSTRACT FROM AUTHOR]

The use of non-lethal weapons has spread worldwide, being introduced as an alternative to firearms in many countries such as the United States or the United Kingdom. Among non-lethal weapons, conducted electrical weapons have been adopted worldwide, to control unruly suspected criminals or to neutralise violent situations. The stun gun belongs to this category and is the most widely available, with more than 140,000 units in use by police officers in the field in the US, and an additional 100,000 electrical stun guns owned by civilians worldwide. In Italy, the use of conducted electrical weapons by law enforcement has only recently been introduced, with private use and commercialisation still prohibited, mainly due to controversies related to the potential dangers of such devices. Before the official adoption, several experiments had to be carried out, with mechanisms that reproduced the ballistics of the stun gun. Here we present the case of a man who suffered a self-injury trauma to his hand during a ballistics exercise with a crossbow loaded with stun gun probes. [ABSTRACT FROM AUTHOR]

We present theoretical analysis and design considerations of a THz superradiant FEL. We derive analytical expressions for the spectral parameter of THz radiation, emitted superradiantly in a rectangular waveguide using a Longitudinal Section Magnetic mode expansion. The results compare well with numerical simulations using UCLA GPTFEL code. GPT simulations of the accelerator e-beam transport show that the chirp provided by a hybrid photocathode RF gun, can produce tight bunching at the undulator site below σ = 100fs. This enables intense superradiant emission up to 3THz, limited by the beam bunching factor. Phase-space analysis of the beam transport indicates that keeping the beam bunching parameter small enough for higher THz frequency operation is limited by the energy spread of the beam in the gun. [ABSTRACT FROM AUTHOR]

Stromboli is a volcanic island in a persistent state of activity, located off the northern coast of Sicily. The paroxysms have been the most powerful explosive phenomena at Stromboli in the last 150 years. These explosions can produce ballistic projectiles that can heavily affect trails and observation sites as well as hit inhabited areas at lower elevations, down to the coast. On July 3, 2019, a paroxysm significantly affected a great portion of the island with ballistic projectiles. In particular, many decimeter and meter-sized spatter bombs hit the W flank of Stromboli, and ignited multiple fires. In May 2022, we conducted an Unmanned Aerial System photogrammetric campaign over a sector of the W flank of Stromboli that was heavily affected by the paroxysm. The largest clasts were still preserved after 3 years, not disturbed by significant mass wasting phenomena or human interference, and they were not yet hidden by the post-fire regrowth of the brush vegetation. In this study, we constrained the main sources of uncertainty affecting the bombs distribution on the ground, by characterizing a percentage of uncertain clasts, testing various density estimators, and by modeling an areal buffer around the mapped clasts. We produced a 0.18 km2 wide 1.6-cm resolution orthomosaic, a 10-cm resolution Digital Surface Model, and 2813 outlines of the mapped ballistics. Spatial distribution of the ground cover and associated uncertainty were analyzed as a function of the distance and of the angular direction from the source. [ABSTRACT FROM AUTHOR]

A coupled framework of ballistic simulations and an optimized machine learning (ML) model was developed to accurately predict the kinetic energy reduction of a projectile impacting a target. ML models can require a significant number of data points for proper training, testing, and validation. High-performance computing (HPC) resources can be used to simulate the ballistic impacts of various projectiles against several different target materials using appropriate physics-based hydrocodes. Computational modeling can explore areas where experiments would naturally be cost-prohibitive. These hydrocodes can evaluate large parametric spaces varying the projectile and target variables that are required to train an ML model. In this study a large, generated set of data points was used to develop an optimized artificial neural network (ANN) algorithm to create a fast-running model without prior knowledge of the mathematical relationships between all the input and output variables. The optimized ANN model was developed using Optuna in an HPC environment to tune the hyperparameters needed for the ANN model. This fast-running ML model could then be leveraged to investigate designing optimized targets that could protect against different types of projectiles. The results of this work showed that the optimized ANN model predicted the kinetic energy reduction with a mean absolute percentage error of 2.7% across the validation data. Overall, the optimized ANN model showed excellent agreement across the range of data considered by the computational models. [ABSTRACT FROM AUTHOR]

A new area of underwater equipment research focus is the use of underwater unmanned vehicles (UUVs) with launch mechanisms to deploy lightweight and small-sized robots for functions including communication, exploration, and detection. The internal ballistic mathematical model of the underwater launch system for small robots is established in this paper. The internal ballistic parameters and the robot displacement and velocity change rule over time are obtained. The optimization calculation of the crucial parameters to be determined by the particle swarm algorithm is completed. Following optimization, the gas cylinder's initial pressure is 2 MPa, its capacity is 30 L, its opening area is 9.683 × 10−5 m2, and its opening time is 0.02 s. A numerical simulation is performed for the small robot's underwater launch process, based on the mathematical and physical model supplied by Fluent 2020 software. The results yield the robot's motion law and the properties of the flow field during the launch process. The purpose of the underwater launcher experiment is to determine the robot's motion characteristics. The accuracy of the theoretical model is confirmed by comparing and analyzing the numerical simulation results with the actual data. [ABSTRACT FROM AUTHOR]

Ballistics is an area of flight, and fewer subjects were of greater importance to nation states in the eighteenth century. William Mountaine who published on the topic in 1747 and 1781, wrote: 'It is not possible in the nature of things for any one kingdom to continue long in a state of peace and tranquility', and 'the art of gunnery has from time to time engaged the attention of the most eminent mathematicians'. This paper describes the slow up-take of ideas, first put forward explicitly by Benjamin Robins in 1742, which challenged the belief that air resistance could be neglected in the flight of cannon balls, and asks why it could be, that for a topic so pressing, a clearly wrong mathematical theory was upheld for so long. While considering a number of factors, it argues the attraction of beautiful and simple geometry can be beguiling. [ABSTRACT FROM AUTHOR]

The object of research is the complex realm of energy localization and coherent ballistic electronic transport within low-dimensional silicon quantum wires, specifically those doped with germanium atoms. Unlike their three-dimensional counterparts, low-dimensional systems exhibit unique electronic transport behaviors, necessitating novel analytical approaches for a comprehensive understanding. The core of this investigation leverages the Phase Field Matching Theory (PMFT) and the tight-binding (TB) approximation, sophisticated methodologies that enable a deep dive into the quantum mechanical nuances of these systems. Through this lens, we examine the intricate dynamics of dispersion relationships, phase factors, group velocities, and notably, the impact of defects introduced by the germanium doping. This research meticulously analyzes how these defects affect electronic and thermal conductivities, along with densities of states, offering new insights into the role of Fano resonances in the fluctuation of transmission and reflection spectra. These resonances, we find, are crucially dependent on the nature of the defects, their configuration, and the electronic parameters in their vicinity, underscoring the nuanced interplay between material composition and electronic properties in low-dimensional systems. The implications of our findings extend far beyond the theoretical. They pave the way for significant advancements in nanotechnology and the design of electronic devices, highlighting the potential for creating more efficient, high-performance components. Furthermore, this work proposes a framework for developing non-destructive testing methodologies that could revolutionize material science by enabling the precise analysis of defects in low-dimensional systems without causing damage. This is particularly critical for the ongoing development of materials with optimized properties for various applications, from electronics to energy storage. In essence, this research not only enriches our understanding of the physics governing low-dimensional systems but also offers practical insights into leveraging these properties for technological innovation. By bridging the gap between theoretical physics and material science, our study sets the stage for the next generation of electronic components and non-destructive evaluation techniques, marking a significant step forward in the application of quantum mechanics to real-world challenges. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) may have a crucial role in the forensic documentation and analysis of firearm injuries. The aim of this forensic ballistics case study was to explore whether two types of expanding bullets and a full metal-jacketed bullet could be differentiated by inspecting bullet fragments and fragmentation pattern in CT. Three types of.30 caliber bullets (full metal-jacketed Norma Jaktmatch, expanding full-copper Norma Ecostrike, and expanding soft-point Norma Oryx) were test fired from a distance of 5 m to blocks of 10% ballistic gelatine. CT scans of the blocks were obtained with clinical equipment and metal artifact reduction. Radiopaque fragments were identified and fragmentation parameters were obtained from the scans (total number of fragments, maximum diameter of the largest fragment, distance between entrance and the closest fragment, length of the fragment cloud, and maximum diameters of the fragment cloud). The fragmentation patterns were additionally visualized by means of 3D reconstruction. In CT, the bullet types differed in several fragmentation parameters. While the expanding full-copper bullet Ecostrike left behind only a single fragment near the end of the bullet channel, the soft-point Oryx had hundreds of fragments deposited throughout the channel. For both expanding bullets Ecostrike and Oryx, the fragments were clearly smaller than those left behind by the full metal-jacketed Jaktmatch. This was surprising as the full metal-jacketed bullet was expected to remain intact. The fragment cloud of Jaktmatch had similar mediolateral and superoinferior diameters to that of Oryx; however, fragments were deposited in the second half of the gelatine block, and not throughout the block. This case study provides a basis and potential methodology for further experiments. The findings are expected to benefit forensic practitioners with limited background information on gunshot injury cases, for example, those that involve several potential firearms or atypical gunshot wounds. The findings may prove beneficial for both human and wildlife forensics. [ABSTRACT FROM AUTHOR]

In examining deaths resulting from gunshot wounds, it is important to describe the wound pathway created by the projectile. Forensic pathologists must identify all entrance and exit wounds and account for all projectiles. Occasionally, confusion arises as to whether a skin defect represents an entrance wound or not, an exit wound, or some other type of wound. Herein, we propose the descriptor "bullet track skin defect" as a formal description for a superficial skin defect created along the pathway of a projectile within the body. Specifically, we define the "bullet track skin defect" as a partial‐ or full‐thickness skin defect produced by a projectile traveling beneath the skin in a relatively tangential fashion as part of a wound pathway within the body. It is somewhat analogous to a traditional graze or superficial tangential wound, wherein the projectile traveling outside the body strikes the skin tangentially from above, without entering the body. However, the projectile is already traveling within the body with the bullet track skin defect, disrupting the skin tangentially from below rather than from above, without exiting the body. Although these defects are not a common presentation of gunshot wounds, they are certainly not rare. With this case series, we suggest that such defects may be referred to as "bullet track skin defects." Alternative language that can substitute for "bullet track skin defects" includes "bullet track skin wounds" or "bullet track cutaneous defects." [ABSTRACT FROM AUTHOR]

Purpose. Development of an approximate nonlinear model for the solution of the external ballistics problem with determination of the nonlinear system parameters and development of a methodology for calculating the aerodynamic characteristics of the cargo, located on the external suspension of unmanned aerial vehicle (UAV) in order to increase the efficiency of their delivery to the specified landing target by means of asymptotic approach with given parameters of the studied system and external load. Methodology. The development of an effective model was carried out using analytical and numerical research algorithms based on a nonlinear system of differential equations in a general form with time-varying coefficients. In order to obtain a solution to the nonlinear problem of external ballistics in a two-dimensional formulation, the assumption of a significant influence of the projection of the velocity function on the ordinate axis in relation to the component on the abscissa axis is introduced. The problem is reduced to the solution of a related system of differential equations with variable coefficients along the corresponding coordinates using the asymptotic approach for a small parameter of the coefficient of frontal aerodynamic resistance. Applied mathematical analysis and modeling have been used for the problem formulation considering studied environmental parameters. Findings. Analytical dependences of the nonlinear problem of ballistics and application of finite-element analysis (FEA) with respect to the cargo motion from the UAV in the presence of the initial speed and wind load in the plane of motion are proposed. It is shown that the obtained analytical solution is correlated with the direct numerical calculation of the basic differential equation with respect to the ordinate axis. Originality. A mathematical nonlinear model of the dynamic process is proposed, assuming the prevailing influence of the speed function along the ordinate axis compared to the function along the abscissa axis. To obtain an approximate analytical solution of the basic nonlinear system of differential equations with variable coefficients the asymptotic perturbation method is applied. The dependence for the axial displacement function is presented considering actual time-flight parameter. Practical value. The obtained analytical dependencies for estimating the time and distance reaching the target with the initial speed of movement and the presence of wind load can be used in applied problems of mathematical physics and engineering calculations of functional dependencies and control of the cargo delivery process and target reaching from an UAV. The obtained analytical results and the solution algorithm can be integrated into applied problems of mathematical physics and engineering calculations, particularly the development of ballistic system control algorithms. [ABSTRACT FROM AUTHOR]

This review covers the effect of ageing on solid gun and rocket propellants in terms of their ballistic properties. A brief overview of the types of methods, which can be used to determine such parameters, is provided and the literature is described in terms of broad motivation areas for the research. It has been demonstrated that understanding the effects and outputs of propellants, and how these might be affected by ageing, remains an important area of research in the field of energetic materials. [ABSTRACT FROM AUTHOR]

Low velocity ballistic deformation behavior of closed-cell aluminum metal foam targets fabricated by powder metallurgy technique has been investigated. The metal matrix of aluminum (60 micron) was mixed with carbamide (CH4N2O) particles of size one mm. Green samples were obtained by compacting the mixture followed by sintering process using a muffle furnace and the metallic foam thus obtained had an average pore size of 1.5 mm. Compared to metallic material, significant reduction in hardness and density was observed when the porosity was increased from 5 to 30%. Using a gas gun setup, low velocity (100 m/s and conical projectile) ballistic experiments were conducted on metal foam targets to understand the deformation behavior. Not any penetration of the projectile was observed when the percentage of porosity was less than 5%. When the percentage of porosity was increased, the projectile was able to perforate the target as the fracture toughness decreases. The size of fragmented areas of the perforated targets and depth of penetration (DoP) of the projectile were measured. Decrease in DoP (improved ballistic resistance) was observed with the increase in relative density of the closed foam target. Even though the projectile could perforate the foam target, no cracks were observed which enhances the suitability of the metal foams to be used as structural applications of defense vehicles. [ABSTRACT FROM AUTHOR]

As one of the most widely used personal protective equipment (PPE), body armors play an important role in protecting the human body from the high-velocity impact of bullets or projectiles. The body torso and critical organs of the wear may suffer severe behind-armor blunt trauma (BABT) even though the impactor is stopped by the body armor. A type of novel composite material through incorporating shear stiffening gel (STG) into ethylene-vinyl acetate (EVA) foam is developed and used as buffer layers to reduce BABT. In this paper, the protective performance of body armors composed of fabric bulletproof layers and a buffer layer made of foam material is investigated both experimentally and numerically. The effectiveness of STG-modified EVA in damage relief is verified by ballistic tests. In parallel with the experimental study, numerical simulations are conducted by LS-DYNA® to investigate the dynamic response of each component and capture the key mechanical parameters, which are hardly obtained from field tests. To fully describe the material behavior under the transient impact, the selected constitutive models take the failure and strain rate effect into consideration. A good agreement between the experimental observations and numerical results is achieved to prove the validity of the modelling method. The tests and simulations show that the impact-induced deformation on the human body is significantly reduced by using STG-modified EVA as the buffering material. The improvement of protective performance is attributed to better dynamic properties and more outstanding energy absorption capability of the composite foam. [ABSTRACT FROM AUTHOR]

This paper is investigating the use of composite armour reinforced by nanomaterials, for the protection of light armoured (LAV) and medium armoured military vehicles (MAV), and the interaction between the composite materials and high-performance ballistic projectiles. Four armour materials, consisted of front hybrid fibre reinforced polymer cover layer, ceramic strike-face, fibre reinforced polymer intermediate layer and the metal matrix composite reinforced backplate, were manufactured and assembled by adhesive technology. The proposed laminated protection system is suitable for armoured ground vehicles; however, it could be used as armour on ground, air and naval platforms. The design of the protection system, including material selection and thickness, was elaborated depending on the performance requirements of Level 4 ＋ STANAG 4569 military standard (projectile 14.5 mm ( 114 mm API B32) and especially on a design philosophy which is analysed with the specifications. The backplate of this new composite is a hybrid material of Metal Matrix Composite (MMC) reinforced with carbon nanotubes (CNTs), manufactured with the use of powder metallurgy technique. The composite backplate material was morphologically, mechanically and chemically analysed. Results show that all plates are presenting high mechanical properties and ballistic characteristics, compared to commonly used armour plates. Real military ballistic tests according to AEP - STANAG 4569 were carried out for the total composite armour systems. After the ballistic tests, AA2024-CNT3 showed the best protection results, compared with the other plates (AA2024-CNT1 and AA2024-CNT2), with the projectile being unable to fully penetrate the composite plate. [ABSTRACT FROM AUTHOR]

To accelerate the practicality of electromagnetic railguns, it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore damage. In this paper, a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun, and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network (PFN) is carried out. Various test methods such as spectrometer, fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity, transient magnetic field strength and stress-strain of rail. Combining the simulation results and experimental data, the damage condition of the contact surface is analyzed. [ABSTRACT FROM AUTHOR]

In this paper, the numerical simulation method is used to study the ballistic performances of hourglass lattice sandwich structures with the same mass under the vertical incidence of fragments. Attention is paid to elucidating the influences of rod cross-section dimensions, structure height, structure layer, and rod inclination angle on the deformation mode, ballistic performances, and ability to change the ballistic direction of fragments. The results show that the ballistic performances of hourglass lattice sandwich structures are mainly affected by their structural parameters. In this respect, structural parameters optimization of the hourglass lattice sandwich structures enable one to effectively improve their ballistic limit velocity and, consequently, ballistic performances. [ABSTRACT FROM AUTHOR]

A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles (RMPs) impacting liquid-filled tanks, and the corresponding hydrodynamic ram (HRAM) was studied in detail. PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process. The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s. The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system, and further compared to those of steel and aluminum projectiles. Significantly different from the conical cavity formed by the inert metal projectile, the cavity formed by the RMP appeared as an ellipsoid with a conical front. The RMPs were demonstrated to enhance the radial growth velocity of cavity, the global HRAM pressure amplitude and the front panel damage, indicating the enhanced HRAM and structural damage behavior. Furthermore, combining the impact-induced fragmentation and deflagration characteristics, the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed. The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis. Finally, the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed. It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior. [ABSTRACT FROM AUTHOR]

A terminal ballistic analysis of the effects of 7.62 mm X 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study. The findings of an instrumented ballistic testing combined with 3D advanced numerical simulations performed using the IMPETUS Afea® software yielded the conclusions. The experimental verification proved that slight differences in the pitch-andyaw angles of a projectile upon an impact caused different damage types to the projectile's core. The residual velocities predicted numerically were close to the experimental values and the calculated core deviations were in satisfactory agreement with the experimental results. An extended matrix of the core deviation angles with combinations of pitch-and-yaw upon impact angles was subsequently built on the basis of the numerical study. The presented experimental and numerical investigation examined thoroughly the influence of the initial pitch and yaw angles on the after-perforation projectile's performance. [ABSTRACT FROM AUTHOR]

Machine learning (ML) is well suited for the prediction of high-complexity, high-dimensional problems such as those encountered in terminal ballistics. We evaluate the performance of four popular ML-based regression models, extreme gradient boosting (XGBoost), artificial neural network (ANN), support vector regression (SVR), and Gaussian process regression (GP), on two common terminal ballistics' problems: (a) predicting the V50 ballistic limit of monolithic metallic armour impacted by small and medium calibre projectiles and fragments, and (b) predicting the depth to which a projectile will penetrate a target of semi-infinite thickness. To achieve this we utilise two datasets, each consisting of approximately 1000 samples, collated from public release sources. We demonstrate that all four model types provide similarly excellent agreement when interpolating within the training data and diverge when extrapolating outside this range. Although extrapolation is not advisable for ML-based regression models, for applications such as lethality/survivability analysis, such capability is required. To circumvent this, we implement expert knowledge and physics-based models via enforced monotonicity, as a Gaussian prior mean, and through a modified loss function. The physics-informed models demonstrate improved performance over both classical physics-based models and the basic ML regression models, providing an ability to accurately fit experimental data when it is available and then revert to the physics-based model when not. The resulting models demonstrate high levels of predictive accuracy over a very wide range of projectile types, target materials and thicknesses, and impact conditions significantly more diverse than that achievable from any existing analytical approach. Compared with numerical analysis tools such as finite element solvers the ML models run orders of magnitude faster. We provide some general guidelines throughout for the development, application, and reporting of ML models in terminal ballistics problems. [ABSTRACT FROM AUTHOR]

The paper presents the methodology used to digitally document the cavities preserved in the northern city wall of ancient Pompeii, to obtain a detailed documentation of the visible ballistic traces attributed to the impact of Roman artillery during the siege of Sulla in 89 BC, in the area from the Vesuvio to the Ercolano Gate. Building on previous studies by the team, authors intend to illustrate the workflow carried out to analyse the morphological characteristics of the existing traces by means of reality-based 3D digitsl models. These virtual replicas are intended to improve the knowledge of selected case studies due to their high relevance. In addition, some stone projectiles still preserved in the Antiquarium will be analysed. The final objective is to define a suitable approach for quantifying the terminal ballistics of Roman artillery based on conclusive evidence, thus allowing not only the virtual, but also the physical reconstruction of the launching weapons used in the war event. [ABSTRACT FROM AUTHOR]

The definitions of stored gravitational energy are given. The value of the limited gravitational energy of two massive mutually nonpenetrating balls is calculated. It is established that the stored gravitational energy is always positive. A formula is presented for the maximum possible gravitational energy of two massive balls, which can be used to estimate the energy of the merger of space objects, in particular, gaseous, dusty, and plasma, as well as for ballistic calculations of space flights. [ABSTRACT FROM AUTHOR]

In a tidal disruption event (TDE), a star is destroyed by the gravitational field of a supermassive black hole (SMBH) to produce a stream of debris, some of which accretes onto the SMBH and creates a luminous flare. The distribution of mass along the stream has a direct impact on the accretion rate, and thus modelling the time-dependent evolution of this distribution provides insight into the relevant physical processes that drive the observable properties of TDEs. Analytic models that only account for the ballistic evolution of the debris do not capture salient and time-dependent features of the mass distribution, suggesting that fluid dynamical effects significantly modify the debris dynamics. Previous investigations have claimed that shocks are primarily responsible for these modifications, but here we show – with high-resolution hydrodynamical simulations – that self-gravity is the dominant physical mechanism responsible for the anomalous (i.e. not predicted by ballistic models) debris stream features and its time dependence. These high-resolution simulations also show that there is a specific length-scale on which self-gravity modifies the debris mass distribution, and as such there is enhanced power in specific Fourier modes. Our results have implications for the stability of the debris stream under the influence of self-gravity, particularly at late times and the corresponding observational signatures of TDEs. [ABSTRACT FROM AUTHOR]

The problems of the motion and destruction of large cosmic bodies under the influence of thermal and force loads in the Earth's atmosphere are considered. Based on the modified physical theory of meteors, a mathematical model of the trajectories of the motion of such bodies during the penetration of the planet's atmosphere is constructed. A computational experiment is carried out for known meteoroids selected as the reference ones in order to determine the effect of the ballistic parameters of the entry of these meteoroids (the angle of inclination of the trajectory to the Earth's surface and velocity) on the process of their destruction in the Earth's atmosphere. It is shown that these characteristics have a significant influence on the motion and destruction of cosmic bodies. [ABSTRACT FROM AUTHOR]

At present, compound targets are usually used to evaluate the mechanism of weapon injury and killing efficiency as well as the protective performance of soft armor. In order to study the ballistic impact response of the skin-gelatin composite target under the protection of UHMWPE panel, the structural design scheme of UHMWPE panel with different specifications was drawn up and prepared. Ballistic impact experiments were carried out on the UHMWPE panel with 7.62 mm pistol projectile, and the damage morphology, residual velocity and energy absorption mechanism of the target plate were analyzed. The finite element models of 7.62 mm pistol bullet penetrating UHMWPE panel and UHMWPE panel-skin-gelatin were constructed, and the impact response characteristics and damage morphology of the composite target were analyzed under different area densities, incident velocities and angles of attack. The results showed that different specifications and processes will affect the protective performance of UHMWPE panel. With the increase of incident velocity and angle of attack, the concave depth of the panel becomes larger and the damage becomes more serious. Furthermore, in the process of penetration, the constraint definition of the model will affect the stress propagation of the composite target. This study provides a new idea for the evaluation of weapon injury mechanism and killing efficiency and the evaluation of protective performance of body armor. [ABSTRACT FROM AUTHOR]

A detailed mapping of volcanic ballistic projectiles emplaced in a defined area, represents the starting point to derive preparatory data in hazard and risk studies of ballistics phenomena. Considering as case study the 3rd July 2019 paroxysmal eruption occurred at Stromboli volcano, we map and analyse at very high spatial resolution (8 cm) the distribution of the ballistic spatter clasts emplaced on the E flank of the volcano. The resulting map identifies and reproduces as geospatial polygon elements 152,228 spatter clasts with areal dimensions from 0.03 to 4.23 m2. Dispersed on 0.407 km2, the spatters cover an area of 29,000 m2 corresponding to an erupted products volume from 2.3 to 7.0 × 103 m3, calculated here for the first time. Spatial analyses indicate that the area mostly affected by the clasts emplacement is between N67.5 and N135 directions, identifying a preferential deposition between N112.50 and N123.75 directions. The clasts size distribution rapidly decreases with the size increase, highlighting a nearly constant ratio small/large clasts regardless the distance from the vent. Finally, additional investigations reveal that clasts dispersion parameters decrease progressively with the distance from the vent only along one direction (N67.5), highlighting how the morphology influences the deposition and remobilisation of mapped ballistics. [ABSTRACT FROM AUTHOR]

A mathematical simulation of the internal ballistics of a shot from a gun, depending on the design of the charge of the gun, has been performed. A general system of equations defining the unsteady movement of a two-phase gas–powder mixture in the channel of the barrel of a gun in the one-dimensional approximation is presented. Results of simulation of a shot from a gun charged with tubular powder or chopped powder are presented. The influence of the gradual ignition of a powder in a gun and of its nonstationary and erosion burning in it on the parameters of the ballistic process in the gun and the influence of the mass and disposition of an igniter in the gun on the dynamics of a shot from it were investigated. [ABSTRACT FROM AUTHOR]

Fluctuations in outer space's temperature would affect the spacecraft's regular operation. This paper aims to study the temperature influences of the aluminum honeycomb buffer in the tether-net launcher. Firstly, a buffer structure was designed to attenuate the pyroshock generated by the pyrotechnic device. Secondly, the mechanical properties of aluminum honeycomb at different temperatures were obtained through quasi-static compression experiments. Then, the internal ballistic responses of the launcher were gained by the closed bomb tests and the equivalent classical interior ballistic model. Finally, the recoil performance of the launcher with aluminum honeycomb buffer at different temperatures was studied. It is revealed that the aluminum honeycomb crushing force gradually decreases with the temperature increases. The peak pressure, burning rate coefficient and velocity increase while the peak time decreases with the temperature increase for the interior ballistics. For the launcher recoil responses, the average launch recoil decreases if the aluminum honeycomb doesn't enter the dense stage. The impact acceleration, projectile velocity and displacement increase as the temperature increase. The paper spotlights the temperature's influence on the recoil characteristics of the aluminum honeycomb buffer, which provides a new idea for buffering technology of pyrotechnic devices in a complex space environment. [ABSTRACT FROM AUTHOR]

In this research, the ballistic behavior of the ceramic-reinforced aluminum matrix composite plates is investigated to provide an optimal design for protecting against 7.62 mm bullet at the speed of 800 m/s experimentally and numerically. The target materials are Al5083 alloy as the metal matrix and alumina ceramic balls as the reinforcement. To simulate a 3D numerical model, ABAQUS FE code has been utilized. After validation the numerical model by experiments, the effect of ceramic ball weight percentage include 15%, 30% and 45% and the target thickness 20, 25 and 30 mm is considered on the ballistic results like the kinetic energy, residual velocity and depth of penetration. Finally, it was found that the specimen with 25 mm thickness and 30% alumina is optimum based on existing ballistic protection criteria. [ABSTRACT FROM AUTHOR]

A methodology is developed based on the coupling of a finite element code with an optimisation module for the design of land vehicle armouring composed of lightweight aluminium alloy and high strength steel plate. Following an experiment/simulation correlation, a numerical model has been built and calibrated considering monolithic plates and then verified considering a bi-metal protection against tungsten carbide projectile mimicking the core of a 7.62x51 AP8 ammunition. In addition, a method is proposed to obtain the vres - vi curve for the full 7.62x51 AP8 bullet from the vres - vi curve obtained from the core only. [ABSTRACT FROM AUTHOR]