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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]

Artillery designers are always searching for means of improving a gun’s external and internal ballistic properties and this resulted in both new theories surrounding gun construction based on the properties of materials and new methods of building guns capable of firing heavier projectiles to greater ranges. The concept of the accelerator gun sought to achieve the same result without the need for larger and heavier guns and reducing recoil through the use of multiple propellant charges fired sequentially, thus accelerating the projectile without the need for a single high-pressure discharge. It was a quest initiated in France, pursued in the United States and then adopted by a desperate Germany during the latter years of World War 2. [ABSTRACT FROM AUTHOR]

This research manuscript describes the process of degradation of an Armox 600 armour plate during the impact of a 5.56x45 mm SS109 projectile. The creation process of the numerical FEM model of the projectile is presented. The projectile impact angle is set between 15° and 90°, and this phenomenon is investigated via numerical and experimental approaches. The experiment is conducted under the same conditions as the numerical approach to validate the FEM model. The experiments are conducted using a high-speed camera. This research manuscript presents the influence of the projectile impact angle on the degradation of the armour plate and its protection capability for different angles. The results demonstrate the dependence of the transferred energy on the armour plate, speed of the particles after impact, and trace dimensions on the armour plate for different impact angles. [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]

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]

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]

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]

In the era of unmanned war, with the increasing muzzle velocity requirement, the design of gun is significantly restricted by recoil, especially for guns installed on unmanned aerial vehicles. A recoilless gun with combustible cartridge was designed to eliminate recoil and increase projectile velocity, and the influence of main parameters on recoil was studied. First, a design of a recoilless gun with high projectile velocity is proposed based on combustible cartridge case. Next, a classical interior ballistic model is developed during the recoilless gun firing cycle, and the effect of main parameters of interior ballistics on the performance is investigated. Additionally, simple nonlinear fitting formulae are defined to highlight the variation of recoil momentum with the time of interior ballistic model. Finally, numerical simulation results are compared with the test results to validate the feasibility of the design. The experimental results demonstrate that the classical interior ballistic model can be used to accurately analyze the effect of the parameters on the projectile velocity and the recoil reduction efficiency. The projectile velocity of the recoilless gun could raised to 1200 m/s and the recoil momentum could be eliminated almostly. Therefore, the newly designed recoilless gun effectively eliminates the recoil momentum and significantly improves the projectile velocity. The findings should make an important contribution to the field of engineering applications of recoilless gun. [ABSTRACT FROM AUTHOR]

The change of ambient temperature will cause the change of gunpowder burning rate, which will directly affect the ballistic performance of the projectile and cause the change of the overload of the projectile fuze system. In this study, the numerical simulation program of the interior trajectory of a large-caliber gun was established by MATLAB, and the variation rules of the corresponding trajectory parameters at different temperatures were obtained. ANSYS finite element software is used to analyze the force of the projectile fuze system under different ambient temperatures. The results show that under the same loading conditions, with the increase of ambient temperature, the maximum pressure in the gun bore and the muzzle velocity of the projectile increase significantly, and the stress and strain of the projectile fuze system in the bore increase gradually. The numerical simulation results are in good agreement with the theory, which reveals the influence of ambient temperature on the overload in the bore of the projectile fuze system to a certain extent, and provides theoretical support for the study of internal ballistics, charge design and gun use. [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]

Researchers use a variety of target materials, and sometimes combinations of materials, in their archaeological experiments to examine thrust‐spear or projectile penetration, impact angle, durability, and other issues involving prehistoric hunting weaponry. This variety of target materials is beneficial to archaeological science in several ways, but it may also hinder the comparison of results because many of these target materials do not necessarily share similar physical properties. Here, we assess the penetration properties of four different target materials—store‐bought meat, clay, and two types of gelatin—via static penetration tests of a modern broadhead‐tipped arrow and a stone‐tipped projectile attached to an Instron Universal Materials Tester. Our analyses of load‐deflection curves, peak load, and work energy demonstrate how the four target materials are similar in some ways but different in others, which suggests that researchers may strategically employ one or several depending on the question asked or hypothesis tested. [ABSTRACT FROM AUTHOR]

A promising direction in barrel ballistics aimed at increasing the muzzle velocity of a projectile is the use of new propellants as an attached charge. This paper presents an experimental and theoretical method for determining the law of propellant combustion in a manometric experiment (in a closed volume). Within the framework of this method, a small number of experiments could be sufficient to determine a change in the law of combustion during the propellant burnout and depending on pressure. This method is demonstrated on the example of processing three experiments with model high-density propellant. The laws of combustion of high-density propellants, obtained in this study, can later be used to calculate the gas-dynamic parameters of a shot from a barrel system or a nozzle bomb (in a semi-closed volume) using these propellants. [ABSTRACT FROM AUTHOR]

In the frame of an experimental setting, the formation of round-shaped compounded glass fragments on the exit site after gunshots through a windshield was examined. For that purpose, a 9 × 19 mm pistol (HK P30) and two different cartridges containing (a) a full metal jacketed round-nosed projectile and (b) a deformation projectile were used. On the basis of 52 gunshots, the morphology, impact angles and terminal ballistics of occurring compounded glass fragments were examined. The results showed that the compounded glass fragments' morphology allowed for the differentiation of two used projectiles. Fragments were able to cause round-shaped defects in a single cotton layer (T-shirt) with subsequent penetration of up to 2.4 cm into ballistic gelatin (10%, 4 °C). As a function of the projectile type, the compounded glass fragments showed different reproducible impact angles that differed notably from the known conical pattern of expelled glass fragments after bullet penetration. These findings might help to explain the atypical morphology of gunshot wounds with laminated glass as an intermediate target and prevent possible misinterpretations when reconstructing the sequence of events. [ABSTRACT FROM AUTHOR]

To improve the tactical and technical performance of pulse correction projectiles while maintaining stability in uncertain conditions and considering practical engineering constraints, this study performs a multi-objective robust optimization design of the aerodynamic shape and external ballistics of a projectile. The study utilizes an aerodynamic force engineering algorithm and numerical trajectory calculations to obtain the projectile's performance responses within the Latin hypercube design space. To enhance optimization efficiency, a stochastic Kriging surrogate model is established to capture the inherent uncertainty of limited input data. Ultimately, a Pareto optimal solution for the projectile is obtained using a non-dominated sorting multi-objective sparrow search algorithm. The results of this study demonstrate that the consideration of design uncertainty in the robust optimization of pulse correction projectiles leads to significant enhancements in both lateral correction ability and range while satisfying flight stability requirements. Moreover, when compared to deterministic optimization, the performance variability of the design is markedly improved. This research methodology provides valuable insights for optimizing the performance of pulse correction projectiles. [ABSTRACT FROM AUTHOR]

The high recoil force of a high-power gun produces a strong impact on the carrier, which severely limits the application of the high-power gun mounted on vehicles. A gas-controlled side-jet gun was designed to reduce the recoil force, and the gas-solid transient flow in the bifurcated tube of the gun was studied. First, a one-dimensional two-phase interior ballistics model was established considering the gas-solid coupling between the propellant gas and the valve in the front gas tube. Then, the propagation of the rarefaction wave in the barrel was studied, and the flow field distribution in the bifurcated tube was obtained. Finally, the mechanism of recoil reduction was analyzed. Results show that the bifurcated two-phase flow model can be used to accurately analyze the effect of the gas-controlled side-jet gun's parameters on the projectile velocity and the recoil reduction efficiency. The projectile velocities of the gas-controlled side-jet gun and the traditional gun are 955.7 m/s and 960 m/s, respectively. The projectile velocity loss of the gas-controlled side-jet gun is less than 0.5 %. The recoil momentum of the traditional gun and the gas-controlled side-jet gun are 538.62 N·s and 336.68 N·s, respectively. The recoil momentum of the gas-controlled side-jet gun decreases by 37.49 %. Additionally, the single firing time of the gas-controlled side-jet gun (18.91 ms) is less than that of the traditional single-barrel gun (more than 60 ms). Therefore, the newly designed gas-controlled side-jet gun significantly reduces the recoil momentum without losing the projectile velocity and continuous firing mode. [ABSTRACT FROM AUTHOR]

Secondary blast injuries may result from high-velocity projectile fragments which ultimately increase medical costs, reduce active work time, and decrease quality of life. The role of skin penetration requires more investigation in energy absorption and surface mechanics for implementation in computational ballistic models. High-speed ballistic penetration studies have not considered penetrating and non-penetrating biomechanical properties of the skin, including radial wave displacement, resultant surface wave speed, or projectile material influence. A helium-pressurized launcher was used to accelerate 3/8″ (9.525 mm) diameter spherical projectiles toward seventeen whole porcine legs from seven pigs (39.53 ± 7.28 kg) at projectile velocities below and above V50. Projectiles included a mix of materials: stainless steel (n = 26), Si3N4 (n = 24), and acetal plastic (n = 24). Tracker video analysis software was used to determine projectile velocity at impact from the perpendicular view and motion of the tissue displacement wave from the in-line view. Average radial wave displacement and surface wave speed were calculated for each projectile material and categorized by penetrating or non-penetrating impacts. Two-sample t-tests determined that non-penetrating projectiles resulted in significantly faster surface wave speeds in porcine skin for stainless steel (p = 0.002), plastic (p = 0.004), and Si3N4 ball bearings (p = 0.014), while ANOVA determined significant differences in radial wave displacement and surface wave speed between projectile materials. Surface wave speed was used to quantify mechanical properties of the skin including elastic modulus, shear modulus, and bulk modulus during ballistic impact, which may be implemented to simulate accurate deformation behavior in computational impact models. [ABSTRACT FROM AUTHOR]

Copyright of Problems of Mechatronics. Armament, Aviation, Safety Engineering / Problemy Mechatroniki. Uzbrojenie, lotnictwo, Inżynieria Bezpieczeństwa is the property of Index Copernicus International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Weapons and past weapon systems are important research topics in Paleolithic archaeology. Its popularity stems from its relevance for understanding broader technological evolution, subsistence strategies, and human behavior. However, identifying what weapon system was used has proven to be a significant methodological challenge over the last few decades and in spite of what some titles of recent publications suggest, the question is still not resolved. In this paper, we present the results of a ballistic analysis of the four modes of propulsion that are traditionally considered for the Paleolithic period (bow, spear-thrower, hand-cast and thrusting spear). We advocate a stepwise approach to the problem given the multiple variables involved. The goal of this study is to add an essential building block to current understanding by exploring the notion of reactional impact stress (RIS) on the basis of the angle of incidence developed by the different projectiles. Our results show the importance of RIS for accurately understanding the projectile impact phenomenon and the existence of a reproducible and mutually distinct RIS between the four tested weapon systems. These results shed a new light on approaches that have been used previously to examine weapon systems archaeologically, such as those relying on the length of "diagnostic impact fractures". Our results allow the proposition of an alternative approach that appears to hold great potential, in particular for identifying the use of the bow. While a reliable method for recognizing past propulsion modes is not yet established, we conclude that the solution lies within the integration of several fields, more in particular use-wear analysis, fracture mechanics in brittle solids, and ballistics and we progressively move forward in identifying the key building blocks of such a method. [ABSTRACT FROM AUTHOR]

Ballistic resistance is affected by the projectile and armor material used. The character and behavior of the projectile affects its ability to damage and penetrate armor. The velocity, mass and shape of the projectile are the main factors in determining the ability of the projectile to penetrate armor in this case the target plate. Therefore, this study aims to determine and analyze the effect of projectile mass and shape on the velocity with which it penetrates the armor material using a compressed air gun. Armor material as a ballistic test target using carbon steel plate with a thickness of 0.8 mm; 1.2 mm and 1.8 mm. Projectiles of lead materials with different masses and shapes are fired from the air gun under controlled air pressure, set at 2000 Psi, 3000 Psi, and 4000 Psi to provide thrust in the barrel. The plat target is placed at a distance of 5 m from the air gun. Speed gauges are placed after the air gun and after the target plate to determine the projectile's rate before and after passing through the target plate. The test results concluded that the velocity of the projectile ejected from the compressed air gun was influenced by the magnitude of the pressure and the mass of the projectile. The mass of the projectile has a more dominant effect on the velocity of the projectile compared to the amount of pressure applied. Different projectile shapes with the same mass have no significant effect on the velocity. However, the heavier mass projectile outperforms the lighter mass projectile through the target plate. It is required the right combination of velocity and mass of the projectile to be able to penetrate the target plate. [ABSTRACT FROM AUTHOR]

The balancing force of the interior ballistics is an important issue in the design of the recoilless gun. It has been found in practice that the balancing force design method for recoilless guns based on the traditional classical interior ballistic theory cannot guide the balance from the physical mechanism and process. In order to study the unbalanced force experienced by the recoilless gun during the firing of the projectile and the variation law of its various parameters with time, the analysis and calculation method of the balanced interior ballistics is proposed in this article. This method separately models the aerodynamic and propellant combustion processes of the recoilless gun, using the characteristic line method to solve the model numerically. This method can be used to predict the change of the unbalanced force acting on the recoilless gun during the projectile firing of the recoilless gun. The reliability of the algorithm is verified by the interior ballistic performance when China 78 type 82 mm recoilless smoothbore gun launches the projectile. The study found that the unbalance impulse generated by the gas inside the barrel fired by the recoilless gun accounts for only 1.5 % of the total recoil impulse, but it has a great influence on the amount of impulse a shooter has can take. This approach provides a better understanding of this complex internal ballistic process, which has important implications for the design and improvements of recoilless guns. [ABSTRACT FROM AUTHOR]

Launching large (> 1 g) well-characterized projectiles to velocities beyond 10 km s - 1 is of interest for a number of scientific fields, but is beyond the reach of current hypervelocity launcher technology. This paper reports the development of an explosively driven light-gas gun that has demonstrated the ability to launch 8-mm-diameter 0.36-g magnesium projectiles to 10.4 km s - 1 . The implosion-driven launcher (IDL) uses the linear implosion of a pressurized tube to shock-compress helium gas to a pressure of 5 GPa, which then expands to propel a projectile to hypervelocity. The launch cycle of the IDL is explored with the use of down-bore velocimetry experiments and a quasi-one-dimensional internal ballistics solver. A detailed overview of the design of the 8-mm launcher is presented, with an emphasis on the unique considerations which arise from the explosively driven propellant compression and the resulting extreme pressures and temperatures. The high average driving pressure results in a launcher that is compact, with a total length typically less than a meter. The possibility to scale the design to larger projectile sizes (25 mm diameter) is demonstrated. Finally, concepts for a modified launch cycle which may allow the IDL to reach significantly greater projectile velocities are explored conceptually and with preliminary experiments. [ABSTRACT FROM AUTHOR]

Copyright of Problems of Mechatronics. Armament, Aviation, Safety Engineering / Problemy Mechatroniki. Uzbrojenie, lotnictwo, Inżynieria Bezpieczeństwa is the property of Index Copernicus International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The wounding potential of a projectile depends on its kinetic energy. The aim of the study was to investigate the deceleration of non-deforming full metal jacket handgun bullets (FMJ) in gelatine blocks of increasing length. The temporary cavity (TC) was visualized using a SA-X2 Photron camera. 126 test shots in 9 mm nominal calibre were fired under strict temperature control conditions (4°C) at small gelatine blocks ranging from 2 to 12 cm in length. The deposited energy was calculated based on the loss of bullet velocity through high-speed video analysis. The length of the TC was measured, when the TC reached its maximum height. The volume of the TC was approximated by a cylinder. Regression analysis showed a linear correlation between the length of the bullet path and the energy transfer. The constant deceleration of the FMJ bullets in gelatine up to 12 cm bullet path was confirmed across various brands and velocity ranges (270–450 m/s). Higher impact velocities correlated with increased loss of energy in the target medium. The shape of the bullet tip influenced the characteristic of deceleration. The volume of the tubular temporary cavity, derived from high-speed video records, was found to be proportional to the energy transferred. The proposed approach might be a valuable tool in advancing wound ballistics research. • Deceleration of FMJ bullets proportional to bullet path in compact target models. • Higher impact velocities resulted in greater loss of energy in the target medium. • The shape of the bullet tip influenced the characteristic of deceleration. • Proportionality of the temporary cavity to the transferred energy. [ABSTRACT FROM AUTHOR]

The appearance of high-entropy alloys (HEAs) makes it possible for a material to possess both high strength and high ductility. It is with great potential to apply HEAs under extreme conditions such as in the penetration process. In this paper, experiments of WFeNiMo HEA and tungsten heavy alloy (WHA) projectiles penetrating medium-carbon steel were conducted by using the ballistic gun and two-stage light-gas gun that can accelerate projectiles to impact velocities ranging from 1162 m/s to 2130 m/s. Depth of penetration (DOP) at elevated impact velocities of HEA and WHA projectiles were obtained firstly. Combined with the macroscopic and microscopic analysis of the residual projectiles, the transition of the penetration mode of the WFeNiMo HEA projectile was identified systemically. The experimental results indicated that the penetration mode of the HEA projectile changes from self-sharpening to mushrooming with the increase of impact velocity, while for the WHA projectile, the penetration mode is always mushrooming. The microstructure of the residual HEA projectiles showed that the phases tangle with each other and the morphology of the microstructure of the phases differs in the two penetration modes. Besides, the evolution of shear bands and fractures varies in the two modes. The evolution of the microstructure of HEAs causes the sharp-pointed nose to disappear and the HEA projectile ultimately becomes blunt as the impact velocity increases. [ABSTRACT FROM AUTHOR]

The ricochet phenomenon has been studied worldwide for a long time in consideration of its significance in ballistics. A ricochet projectile has proven to be worthless to its launcher, as warheads fail to penetrate the interior of targets and strike the facilities and personnel of enemies effectively. A large portion of related research has been dedicated to avoiding ricocheting, which mainly focuses on improving the penetration ability of a projectile in order to obtain a better penetration effect, while investigations on the proactive protection of key targets from damage caused by a ricochet projectile are minor. This study analytically explores the ricochet range of a projectile obliquely penetrating a thick steel target. Firstly, the moment of momentum equation of the ricochet projectile based on theoretical mechanics is utilised to analytically calculate its trajectory, where a mathematical model of a two-stage ricochet impacting is established through the geometrical analysis of the ricochet process for determining the ricochet range of a projectile and the size of the bulletproof structure. Then, impact experiments of a projectile obliquely penetrating thick steel targets at different striking velocities and inclination angles are carried out, and the influences of the striking velocity and angle of attack on the damage pattern, area and penetration depth are discussed to identify the ricochet phenomenon. Moreover, the deflection angle of the ricochet projectile is computed, which is compared with the experimental measurements in order to validate the accuracy of this proposed model. This proposed research may promote security protection during live-firing training and provide a theoretical foundation for the optimisation of purposeful protection. [ABSTRACT FROM AUTHOR]

In shooting crimes, ballistics tests are often recommended in order to reproduce the wound characteristics of the involved persons. For this purpose, several "simulants" can be used. However, despite the efforts in the research of "surrogates" in the field of forensic ballistic, the development of synthetic models needs still to be improved through a validation process based on specific real caseworks. This study has been triggered by the findings observed during the autopsy performed on two victims killed in the same shooting incident, with similar wounding characteristics; namely two retained head shots with ricochet against the interior wall of the skull; both projectiles have been recovered during the autopsies after migration in the brain parenchyma. The thickness of the different tissues and structures along the bullets trajectories as well as the incident angles between the bullets paths and the skull walls have been measured and reproduced during the assemblage of the synthetic head models. Two different types of models ("open shape" and "spherical") have been assembled using leather, polyurethane and gelatine to simulate respectively skin, bone and soft tissues. Six shots have been performed in total. The results of the models have been compared to the findings of post-mortem computed tomography (PMCT) and the autopsy findings.Out of the six shots, two perforated the models and four were retained. When the projectile was retained, the use of both models allowed reproducing the wounds characteristics observed on both victims in terms of penetration and ricochet behaviour. However, the projectiles recovered from the models showed less deformation than the bullets collected during the autopsies. The "open shape" model allowed a better controlling on the shooting parameters than the "spherical" model. Finally, the difference in bullet deformation could be caused by the choice of the bone simulant, which might under-represent either the strength or the density of the human bone. In our opinion, it would be worth to develop a new, more representative material for ballistic which simulates the human bone. [ABSTRACT FROM AUTHOR]

In view of the influence of projectile-barrel coupling on tank firing accuracy, a finite element model of projectile-barrel coupling based on vibration theory was established. By defining user subroutines to simulate the change of the physical field of interior ballistics, the load condition under which the propellant gas radial pressure acts on the inner wall of the barrel and varies with the motion of the projectile is realized. On this basis, the dynamic characteristics of projectile-barrel coupling considering the radial effect of propellant gas pressure were studied. The reference targets such as cradle, projectile and muzzle were selected for analysis, and compared with the situation without considering the radial effect of propellant gas pressure. The results show that the motion trend of the projectile in the bore and the response law of muzzle vibration change greatly when considering the radial effect of propellant gas pressure and these changes may seriously affect the law of projectile dispersion. The radial effect of propellant gas pressure can cause stronger dynamic response, which cannot be ignored in the simulation of artillery firing process. This work provides a practical reference for further study of tank firing accuracy. [ABSTRACT FROM AUTHOR]

A new model has been defined that enables the estimation of the lethal radius (radius of efficiency) of HE (High Explosive) artillery projectiles against human targets. The model is made of several modules: CAD (Computer Aided Design) modeling, fragment mass distribution estimation, fragment initial velocity prediction, fragment trajectory calculation, effective fragment density estimation, and high explosive projectile lethal radius estimation. The results were compared with the experimental results obtained based on tests in the arena used in our country, and the agreement of the results was good. This model can be used in any terminal-ballistics scenario for high explosive projectiles since it is general, parametric, fast and relatively easy to implement. [ABSTRACT FROM AUTHOR]

It is important to know the process of hot spot creation to improve the safety of working with melted TNT. One of the probabilities is the air bubbles in TNT that melted during the firing and internal ballistics, which are the results of casting problems. Thus, in this paper, the accuracy of this probability was studied. Melted TNT is a highly viscous fluid, so in this study by improving the numerical code, the effects of the temperature‐dependent physical properties have been seen in the calculations. The results show that the viscosity work makes the bubble heated and rises, its temperature in comparison with the fluid environment. But the variations are a maximum of 4 °K. Therefore, it seems that the studied factors in this paper can′t be the reason for melted TNT undesirable ignition. [ABSTRACT FROM AUTHOR]

As a parameter important ballistic, the research about polygonal and grooved barrels' behavior has not been widely carried out. The pressures, velocities, stresses, deformations, and strains generated by the firing of 9 mm × 19 mm ammunition in weapons with polygonal barrels are analyzed numerically and experimentally, compared with those generated in pistols with grooved barrels. The Finite Element Method with equal boundary and loading conditions was used in both types of guns, specifying the actual materials of the projectile and the barrels. Subsequently, experimental tests were carried out on various weapons with 9 mm ammunitions of 115, 122, and 124 gr. The results show that the 9 mm bullet fired in a polygonal barrel undergoes a maximum deformation towards its exterior of 0.178 mm and interior of 0.158 mm, with stress up to 295.85 MPa. Compared with 0.025 mm maximum external deformation and 0.112 mm internal deformation of 9 mm projectiles fired in a grooved barrel, with stress up to 269.79 MPa. The deformation in the polygonal barrel is in a greater area, but the rifling impression left is less deep, making its identification more difficult. Although there are differences in the stresses and strains obtained, similar velocity and pressure parameters are achieved in the two types of barrels. This has application in the development and standardization of new kinds of barrels and weapons. [ABSTRACT FROM AUTHOR]

A "plated bullet" has a thin layer of electroplated metal covering the lead core of the projectile. In certain situations, this thin layer of electroplated metal can fracture upon discharge of the firearm. When such fracturing occurs, vaporous lead can escape through the fracture lines of the spinning projectile, resulting in a spiral‐shaped deposition of dark residue surrounding a central bullet defect. The spiral‐shaped pattern is referred to as "comet‐tailing," or the "vortex effect." In this report, three homicide cases with associated comet‐tailing are presented. Police, death investigators, and forensic pathologists should be aware of this unique finding. [ABSTRACT FROM AUTHOR]

The main objective of this article is to obtain equations of motion of the spin-stabilized projectile in the presence of non-constant wind. Introducing models allowing utilization of inhomogeneous wind is dictated by new possibilities created by the use of e.g. lidars in the Fire Control Systems (FCS). Constant feed of wind data can replace meteorological messages, increasing the FCS effectiveness. Article contains results of projectile flight simulations which indicate the positive effect that the derived explicit form of the model has when considering software development for modern Fire Control Systems. [ABSTRACT FROM AUTHOR]

Copyright of Archivos de Criminología, Criminalística y Seguridad Privada is the property of Sociedad Mexicana de Criminologia Capitulo Nuevo Leon, A.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper deals with an adaptation of the standard interior ballistics model for the case of amphibious rifle shooting ammunition under water. The adapted mathematical model was validated and experimentally verified using the 5.56 mm underwater projectile shot from the 5.56 mm amphibious rifle. The dependence of the underwater interior ballistic processes on the powder mass was investigated. The results of theoretical mathematic model solution correspond very well with experiment. The described mathematical model and the dependence of the underwater interior ballistic processes on the powder mass can be a reference for designers in the design process of the underwater ammunition or underwater rifle. [ABSTRACT FROM AUTHOR]

Copyright of Radio Electronics, Computer Science, Control is the property of Zaporizhzhia National Technical University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Modelling and simulation of projectile flight is at the core of ballistic computer software and is essential to the study of performance of rifles and projectiles in various engagement conditions. An effective and representative numerical model of projectile flight requires a relatively good approximation of the aerodynamics. The aerodynamic coefficients of the projectile model should be described as a series of piecewise polynomial functions of the Mach number that ideally meet the following conditions: they are continuous, differentiable at least once, and have a relatively low degree. The paper provides the steps needed to generate such piecewise polynomial functions using readily available tools, and then compares Piecewise Cubic Hermite Interpolating Polynomial (PCHIP), cubic splines, and piecewise linear functions, and their variant, as potential curve fitting methods to approximate the aerodynamics of a generic small arms projectile. A key contribution of the paper is the application of PCHIP to the approximation of projectile aerodynamics, and its evaluation against a set of criteria. Finally, the paper provides a baseline assessment of the impact of the polynomial functions on flight trajectory predictions obtained with 6- degree-of-freedom simulations of a generic projectile. [ABSTRACT FROM AUTHOR]

A fiber-optic confocal sensor for noncontact ballistic measurements is described. Determination of motion at velocities of 1.7 km/s with an uncertainty as small as ±0.3% is demonstrated for both a projectile and a free-surface target. The fibers detect the passage of the object at their conjugate image points created by low F/# optics. This results in an output signal comprising a train of sharp pulses each precisely identifying when the ballistic object traverses an image point. Since the ballistic object does not contact the sensor at the time of imaging, the measurements do not perturb the motion, enabling multi-fragment measurement, as well as repetitive measurements of the same object point. [ABSTRACT FROM AUTHOR]

Sabot asymmetric discard after the projectile being launched from the muzzle at various angles of attack and 4Ma is investigated. This is implemented by the coupling computational fluid dynamics (CFD) and six degrees-of-freedom exterior ballistic code through the unstructured dynamic mesh and user defined function. The flow field characteristics during sabot discard process and the trajectory parameters of all three sabots have been obtained. In addition, the aerodynamic coefficients of the projectile are also obtained. The numerical results show that the asymmetric discard of sabot is more obvious along with the increasing angle of attack. Moreover, the aerodynamic forces of projectile have a larger change and the pressure distribution of its surface is more asymmetric and complex. This means the aerodynamic interference at a non-zero angle of attack contributes more significantly to shooting dispersion and flight stability than that at zero angle of attack and the influence increases as the angle of attack increases.

In order to study the two-dimensional rheological behavior of a long-rod projectile penetrating into steel target, a two-dimensional elbow-streamline penetration model was developed based on long-rod projectile hydrodynamic penetration model, mass conservation during penetration and elbow model. The impact velocity, reference point angle and reference point radius are considered in the proposed model. The material flow around the nose of tungsten long-rod projectile penetrating into a steel target was analyzed based on the proposed model and compared with the test results. The results show that the material flow around the tungsten long-rod projectile nose is non-uniformly distributed, and the flow velocity on the outer side is less than that on the inner side. The pressure on the long-rod projectile nose material is distributed gradiently. The proposed model is used to describe the material flow of long-rod projectile nose during penetration, and explain the process of transition from fluid to solid in the projectile nose at the final stage of penetration. It reveals the relation between the change of ballistics channel and the penetration state transition of projectile. [ABSTRACT FROM AUTHOR]

The appearance of new projectile propulsion modes is viewed as an important element for understanding human behaviour during the Palaeolithic. Because the organic components of hunting weapons (the bow, spear‐thrower and arrow, and spear shaft) are only rarely preserved archaeologically, some effort has been invested in experiments to explore how the projecting modes could be identified through the analysis of stone points. The kinetic energy developed by each mode of propulsion has been considered a key variable in these experiments. However, the data used in these studies generally come from a few ballistic studies, with varied results. We present the results of a systematic study conducted with a ballistic pendulum and combined with a classic ballistic analysis. We quantified and compared the kinetic energy developed by the four standard modes of propulsion known for the Palaeolithic. The kinetic energy values that we attained, especially those measured for thrusting spears, clearly differ from what has been assumed up to now, and thus challenge current models on the evolution of hunting technology. [ABSTRACT FROM AUTHOR]

This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m2 Kevlar KM2+ fabric performs better per weight than 467 g/m2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. [ABSTRACT FROM AUTHOR]

Firing accuracy is a critical quantity of interest in the performance analysis of electromagnetic railgun (EMRG) exterior ballistics. Since the simulation technique is always used to simulate the complex physical system at a low cost, it is employed to evaluate the firing accuracy of railgun projectile with uncertainty in this paper. An exterior ballistics simulation model of the railgun, including 3-DOF flight mechanical model, relative kinematic model, and guidance law model, is developed to simulate the ballistics behavior in the missile target intercept mission. The firing accuracy is studied in this paper to compare the capability of EMRG with different ranges and muzzle velocities. In order to explore the firing accuracy of the guided projectile, the guidance precision analysis and ballistics uncertainty quantification are studied. In the guidance precision analysis, the shot range and efficiency are used to make a comparison. In addition, the sensitivity analysis and firing accuracy analysis are also performed in terms of uncertainty quantification. The simulation results illustrate that the simulation of the guided projectile can give some practical guide to the projectile design of EMRG. [ABSTRACT FROM AUTHOR]

Energy efficiency is a critical quantity of interest in the performance of electromagnetic railgun (EMRG). To improve the energy efficiency of EMRG with the presence of uncertainty, a hybrid robust optimization method is proposed. EMRG simulation model is developed to simulate the behavior of exterior ballistics and the corresponding robust optimization issue is formulated. With the help of the impact factor analysis, several significant factors of energy efficiency are selected as the design variables while the insignificant ones are not taken into account. In the robust optimization, the polynomial chaos expansion approach coupled with Latin hypercube design is proposed to propagate the uncertainty for alleviating the computational burden of fitness function (energy efficiency) evaluation. Then, the genetic algorithm is employed to solve the EMRG energy efficiency optimization problem with the constraint of mean miss distance. The optimization results illustrate that the hybrid robust optimization method is an efficient approach to improve the energy efficiency, which can be applied in the practical application of EMRG projectile design. [ABSTRACT FROM AUTHOR]

In the present paper, the high velocity impact of 9mm soft lead projectile on 10mm and 30mm thick Eglass/ epoxy composites was studied using a 450 kV Flash X-ray radiography (FXR) system. The basic parameters of FXR imaging, such as effect of ratio of target to film (TF) and source to target (ST) distances and X-ray penetration thickness of the composite material were optimized based on clarity and the actual dimensions of the objects. The optimized parameters were used in the FXR imaging of the ballistic event of 9mm soft projectile on E-glass/epoxy composite. The real time deformation patterns of both the projectile and composite target during the ballistic impact were captured and studied at different time intervals. The notable failure modes of the 10mm thick target with time include fibre breakage, bulging on the back side, delamination, recovery of the bulging, reverse bulging and its recovery. However, with increase in thickness of the target to 30mm the only failure mechanism observed is the breaking of fibres. The ballistic impact event was also numerically simulated using commercially available LS-DYNA software. The numerically simulated deformation patterns of the projectile and target at different time intervals are closely matching with the corresponding radiographic images. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the impact-face material of a multi-ply soft armor system was varied to different ratios and tested for the effects on the ballistic performance. It is known that the first few layers of multi-ply soft armor material typically fail inelastically near the system ballistic limit and can be replaced with a "sacrificial" material with other more desirable properties. Previous studies have determined that the ballistic performance of these hybrid systems is largely dependent on the amount of high-performance backing material. However, the extent to which the high-performance fabric can be replaced has yet to be fully quantified and examined. Materials of different properties, namely stainless steel mesh, Makrolon® polycarbonate sheets, and cotton, were used as replacement frontal material for 840 d Twaron® panels, and the hybrid panels were impacted by O1 tool steel right-circular cylinder projectiles fired using a single-stage smooth-bore gas gun. Results show that the ballistic performance is maintained up to a frontal material ratio of about 40%, and off-axis material properties play a role in energy dissipation. [ABSTRACT FROM AUTHOR]