Muzzle Velocity Research Articles

Empirical Models for Predicting Two-Stage Light Gas Gun Muzzle Velocity

Empirical Models for Predicting Two-Stage Light Gas Gun Muzzle Velocity

Preparation and performance studies on organic-inorganic phase change composites based on zeolitic imidazolate and paraffin for reducing gun barrel erosion

With the increasing requirements of tank guns for higher muzzle velocity and faster firing rate, some high energetic additives, such as cyclotrimethylene trinitramine (RDX) and cyclotetramethylene tetranitramine (HMX), have been widely used in high energy gun propellants. Consequently, the gun barrel erosion induced by the burning of high energy gun propellants has been an important issue that affects the lifespan of gun barrels. In order to address this problem, erosion reducing additives, including TiO2, paraffin, polyurethane or a combination of these, were introduced into the gun propellant or propellant charge system to alleviate the gun barrel erosion. In this study, a novel organic-inorganic phase change composite paraffin/ZIF-67 with solid paraffin (SP) as the phase change component and zeolitic imidazolate framework-67 (ZIF-67) as the matrix was designed and prepared as anti-erosion additives. The designed composite has a high thermal storage capacity of 93.88 J/g when the ZIF-67 content is 5 wt%. The erosion reducing effect of paraffin/ZIF-67 was determined by erosion tube test. The results show that the introduction of paraffin/ZIF-67 can improve the erosion-reducing efficiency of gun propellants. Compared with the control sample, the erosion-reducing efficiency of paraffin/ZIF-67 exhibited a faster increase with the increase of their contents, having the maximum erosion-reducing efficiency of 39.2 % when the addition of paraffin/ZIF-67 is 3.2 wt%. The incorporation of paraffin/ZIF-67 in the composites has a cooperative effect of each component on reducing gun barrel erosion. The developed organic-inorganic phase change composites exhibit great potential in the application of reducing gun barrel erosion, providing a new way for the development of erosion reducing additives.

Numerical simulation research on the launch process of pneumatic launch device

Abstract In order to deal with the potential threats posed by low-altitude UAVs, an anti-UAV net-catching device was designed based on the principle of pneumatic launch. The internal ballistic calculation model of the net-catching device during the launch process was established, and the pressure-stabilizing air chamber of the device was numerically simulated. The impact of pressure, air chamber volume, gas channel diameter and barrel length on the performance of the launch device to capture the UAV was analyzed. The internal relationship between different influencing factors on the muzzle velocity and the air pressure drop of a single shot was analyzed. Selecting appropriate internal ballistic characteristics to capture UAVs at different target distances provides theoretical guidance for in-depth research on anti-UAV netting devices.

Numerical investigation of the influence of different barrel lengths on the interior ballistic process within an underwater submerged launch

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.

High-efficiency and low-hazard artillery recoil reduction technology based on barrel gas reflection

Reducing recoil as well as reducing muzzle hazards are important issues in artillery design. This paper presents a barrel gas reflection method for the artillery aiming for efficient recoil reduction while reducing muzzle hazards. The launching process is modeled by coupling the interior ballistic equations and the flow equations of the barrel gas reflection device. The fourth-order Runge–Kutta method was used to solve the model, and the LHS method as well as the Kriging model was used to establish a mapping relationship between the parameters and the effect. To validate the proposed model, shooting experiments are carried out on a 30 mm caliber artillery. The maximum error between the experiment and simulation results was 5.32%. The experiment has demonstrated that the barrel gas reflection method increases the recoil reduction efficiency of artillery by 44.54% and reduces the muzzle hazard by 52.18%. Finally, the barrel gas reflection method can produce effects with the muzzle device at the same time, and it has little effect on the velocity of the projectile muzzle velocity, and it provides a new way of thinking for the development of future artillery recoil reduction technology.

Children's toys no longer: a porcine model study of the lethality of modern air rifles.

We observed modern spring-loaded air rifles reaching velocities similar to small-bore rifles, raising concerns about their potential lethality. After encountering two life-threatening thoracic injuries in our practice, we conducted a study to assess the injuries that a commonly available air rifle could cause in a porcine cadaver model. We conducted shooting experiments from 5 and 10 metres away using a .22 calibre spring-loaded airgun, firing five shots into the anterolateral chest on the left side at both distances. Additionally, we repeated the experiment with ten shots into 10% ballistics gel behind an explanted chest wall to evaluate chest wall penetration reliability. Out of the ten combined shots, six resulted in lethal or potentially lethal injuries, including multiple cardiac injuries. Moreover, we observed chest wall penetration in 9 out of 10 shots, with an average penetration depth of 106mm. Non-life-threatening injuries appeared to be influenced by shot location rather than an inability to penetrate the chest wall. Our study raises significant concerns about the potential lethality of unrestricted air rifles in New Zealand. With muzzle velocities comparable to small-bore rifles, these firearms should be reconsidered in terms of regulation and possibly restricted to gun license holders.

Influence of embedded structure on two-phase reactive flow characteristics for a small combustion chamber with a moving boundary

In special launch scenarios such as armament and aerospace, the scale of the launch system is severely restricted, which causes unstable combustion of propellant. An embedded structure for the small propulsion system driven by solid propellant is proposed to overcome this problem. This study aims to demonstrate the two-phase flow behaviors and launch safety of the combustion chamber with an embedded structure. A two-dimensional two-phase flow model based on the modified two-fluid theory is developed to describe the detailed two-phase flow behaviors in the combustion chamber during launching. Different from most of the existing studies, the constitutive equations determined from actual physical conditions are used to close the system of continuity equations. The numerical results are compared with that of the experiment to verify the accuracy of the numerical model. On this basis, the launch performance of the embedded structure is investigated. The numerical results indicate that the embedded structure facilitates the ignition process and reduces the risk of excessive pressure, but decreases the muzzle velocity at the same time. In addition, the effect of design parameters on launch safety is further investigated. Design parameters directly affect the launch safety, and the selection of reasonable parameters is a useful method for enhancing the launch performance.

Specified Velocity Launching of Reluctance Coil Gun Based on Genetic Algorithm

In this study, a method is proposed to obtain the initial voltage of the capacitor and the initial relative position of the projectile of a reluctance coil gun using a genetic algorithm to make the projectile launch at a specified muzzle velocity with high efficiency. Firstly, the equivalent inductance change during the launching process is used as a link for multi-physics field analysis, and a set of electromagnetic dynamics equations is derived to correct the effect of magnetic saturation on the inductance according to the current value in the coil. Further the set of equations is constructed as a Simulink discretized numerical computational program and called by a genetic algorithm written in MATLAB to approximate the optimal solution by generation-by-generation optimization. When the specified projectile muzzle velocity is set to 10 m/s, the initial voltage of the capacitor calculated using the genetic algorithm is 156 V, and the initial position of the projectile is -14.3 mm. We input the parameters into the finite element analysis model and the launch experiment platform, and the obtained projectile muzzle velocity is 9.67 m/s and 9.8 m/s respectively, and the efficiency is close to the optimal value, also the comparison of voltage and current waveforms also shows that the method proposed in this study is effective.

ВПЛИВ ПОГОДНИХ УМОВ НА РЕЗУЛЬТАТИ ЗАСТОСУВАННЯ КІНЕТИЧНОЇ ЗБРОЇ НЕСМЕРТЕЛЬНОЇ ДІЇ

Currently, when designing non-lethal kinetic weapons, the degree of protection of the target provided by clothing items, especially during cold seasons, is not considered. As a result of the loss of part of the energy of the impact element on deformation and destruction of clothing items, the effects on the target can significantly differ from those calculated for normal conditions and exceed permissible limits. This may lead to the failure of the firing task due to insufficient or excessive action of the impact element on the target. For the purpose of determining the influence of the degree of target protection by clothing items on the results of the action of the impact element, natural experimental studies were conducted using a pneumatic ballistic installation and a target simulator made of ballistic plasticine "Beschussmasse". The results yielded empirical dependencies of the penetration depth of the impact element from its velocity upon meeting the target for several protection variants of the object of weapon application by clothing items. These dependencies can be used during the design of non-lethal kinetic weapons, as well as for selecting models of such weapons from those available to perform firing tasks in specific temperature conditions. The work also draws attention to the need to consider the influence of the temperature of the powder on the burning rate and muzzle velocity of the impact element. To increase the effectiveness of the application of non-lethal kinetic weapons, it is proposed to develop a set of ammunition for such weapons with different masses of powder charge, which would correspond to the ambient temperature and take into account the degree of protection of the object of weapon application by clothing items and the dependency of the burning rate of the powder on the temperature. The direction for further research is to study the influence of the hardness of the impact element of the non-lethal kinetic weapons on the results of its action on the target.

The wounding potential of assault rifles: analysis of the dimensions of entrance and exit wounds and comparison with conventional handguns. A multicentric study.

The appearance of agunshot wound (GSW) is greatly influenced by the velocity of the projectile, where high-velocity projectiles (HVPs) are defined as ballistic agents reaching a muzzle velocity of > 600 m/s fired from assault rifles. The aim of the study is to present and explain the differences in the dimensions of entrance and exit wounds between the most used handguns and assault rifles and to propose a predictor of HVP, i.e., the ratio of exit and entrance wounds (EX/ENR). The surface area of entrance and exit GSWs and the EX/ENR were calculated. 66perforating GSWs produced by NATO FMJ 7.62 × 52 mm and 5.56 × 42 mm fired from assault rifles were assigned to the HVP, while 64 lesions produced by conventional projectiles fired from revolvers and semi-automatic pistols were assigned to the low-velocity projectile (LVP) group. The dimensions of the exit wounds of the HVP group were significantly higher when compared to the LVP group (95% CI 0.9886-2.423, p < 0.05). The HVP group showed significantly higher values for the EX/ENR when compared to the LVP group (95% CI 2.617-7.173, p < 0.05). The evaluation of the EX/ENR can be considered an adequate tool to assess the type of weapon involved and to roughly estimate the associated wounding mechanisms, which can guide both the physician in the management and treatment of the patients affected by GSW, and the forensic pathologist in crime investigation.

OPTIMIZATION OF THE USAGE OF 35 MM ANTI-AIRCRAFT GUN BARRELS IN TERMS OF RELIABILITY AND ECONOMIC EFFICIENCY

The scientific basis for optimizing the use of work resources of 35 mm anti-aircraft gun barrels, enabling their durability to be increased by 25÷100% while improving operational efficiency indicators are presented in this paper. The development of a new approach to assessing the durability and effectiveness of these barrels results from current solutions and capabilities of navigation and targeting systems, new generation projectiles (programmable ammunition with sub-projectiles) and real-time muzzle velocity measurement applications (while main-taining or even increasing the current muzzle velocity and rate of fire). This increases the probability of hitting floating, coastal and flying targets (especially UAVs and RAM). It has been shown that the durability and operational assessment of this class of guns (including economic efficiency) is not determined only by indicators based on the rate of fire, muzzle velocity or second burst of fire. What is now more important is the ability to reduce the rate of barrel destructive processes, resulting from the possibility of shortening the length of firing series. It has been shown that with short series, the barrels wear and the intensity of damage to the reload mechanisms are significantly reduced. The phenomenon of barrel overheating is also limited, and thus operational indicators are improved (average time to failure, continuous operation time, ammunition usage), which significantly reduces the cost of operating the guns.

The effect of ambient temperature on the internal ballistic overload of a large-caliber artillery projectile fuze system

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.

IDENTIFICATION OF THE DISTRIBUTION OF MUZZLE VELOCITY AND MAXIMUM PRESSURE IN THE BARREL FOR A TYPICAL RIFLE

The paper presents the procedure for identifying the distribution of muzzle velocity and the maximum pressure in the barrel for a typical 7.62mm rifle. Input data are collected through the experiment using 50 shots for muzzle velocity and 20 shots for maximum pressure. The distribution is identified with the support of Minitab software. Research results show three distributions suitable with muzzle velocity and maximum pressure in the barrel: the normal, 2P-Weibull and 3P-Weibull. Among them, the 3P-Weibull distribution is best suited to the muzzle velocity and the normal distribution is best suited to the maximum pressure in the barrel. The research results of the paper will help reduce the number of experiments when determining the muzzle velocity and the maximum pressure of the rifle.

Influence of Volume of Air on the Muzzle Velocity of the Projectile

Influence of Volume of Air on the Muzzle Velocity of the Projectile

Velocity dependence of barrel friction

A tribological model is presented that provides a correlation between bullet velocity and friction force in firearms. The model is based on the observation that higher velocities result in lower friction and assumes that the surfaces of the bullet and barrel consist of elastic asperities. The model predicts that as the relative velocity increases, the asperities are less likely to return to their neutral positions. The model was tested using experimental muzzle velocity and gas pressure measurements for caliber 5.56 × 45 bullets and the results were in good agreement with the model predictions. The coefficient of friction obtained with the model is also in line with literature values for very low sliding velocities.

Deep and machine learning architecture for high accuracy prediction of interior ballistics for modular charges

AbstractInterior ballistics modelling intends to calculate physical quantities by solving equations requiring a set of input like thermodynamical properties linked to propellant or mechanical properties like friction coefficients, linked to the system, that are often difficult to assess experimentally. Using a consequent and high‐quality dataset of thousands of 155 mm modular charge experiments, we investigated how deep and machine learning approaches could build an efficient model for predicting muzzle velocity, pressure, and ignition time. After identifying the main variables influencing the physics and several potentially relevant to the machine learning and deep learning algorithms, a stacking ensemble learning model (SEL) was built. It is composed of eight machine learning algorithms and one deep learning algorithm, all as weak learner, reaching a consensus for predicting experimental outputs through a strong learner. The performance assessment, on a 900 experiments test data set that were not used in training, shows a prediction accuracy of 97 % at 1 % accuracy for muzzle velocity, 93 % at 3 % for pressure and 72 % at 5 ms for ignition time. The prediction ability for muzzle velocity within 2 m/s reaches 73 % that can be considered as sufficient. Furthermore, the SEL model even having zero knowledge about physics can discriminate gun barrel erosion effect at high and low pressure. This approach allows to imagine a way of modelling physical phenomena poorly described by physical equations or requiring unmeasurable figures.

Launch Dynamic Simulation of a Compressed-Air Launcher for Fire Suppression

This paper focuses on improving fire suppression performance through the use of compressed-air launching technology. A launch dynamics calculation model of a compressed-air launcher is presented, developed using VC++ programming, to simulate the acceleration process of a fire-extinguishing bomb in a barrel. By analyzing the influences of various structural and initial parameters on interior ballistics variations, the effectiveness of the calculation model and program in accurately simulating the launching process is demonstrated. The calculation results indicate that the bore pressure follows a similar trend to that of traditional gunpowder launching. Additionally, it is found that specific structural parameters, such as nozzle diameter and gas cylinder volume, have a direct impact on interior ballistics variations. Notably, the nozzle diameter positively affects the peak pressure, muzzle velocity, gas transfer efficiency, and launch efficiency. To ensure an optimal launch effect and efficiency, the nozzle diameter should be selected to be more than half of the launcher caliber. Similarly, the gas cylinder volume positively influences the peak pressure and muzzle velocity while negatively affecting the gas transfer efficiency and launch efficiency. Furthermore, the initial pressure in the gas cylinder exhibits a positive linear relationship with both the peak pressure and muzzle velocity but a negative linear relationship with the gas transfer efficiency and launch efficiency. The loading position minimally impacts the peak pressure and muzzle velocity but slightly enhances the gas transfer efficiency and launch efficiency. Finally, it is observed that launch angles do not affect the interior ballistic process. The research findings provide valuable theoretical guidance for determining the working parameters of compressed-air accelerated fire-extinguishing bombs.

Design and Simulation of a Slice-rail and Cylindrical for Multi-Projectile Electromagnetic Launchers

In Electromagnetic launcher (EML) research, beside reasonable L' and high muzzle velocities, there are several key features including multi-turn launching, low field intensity in payload position, high frequency shooting, less unwanted radiation, and so on. Attaining a solution might be feasible by a different structure. In this paper we have studied unequal curved electromagnetic rail launchers (EMRLs) as slice and cylindrical multi-projectile electromagnetic launchers, and the inductance gradient (L') of these structures has been calculated. Making multi-projectile EMRLs using a slice-rail structure is much easier than other plane methods. With a cylindrical multi-projectile EMRL, higher shooting frequency is more feasibly attained and there is no limit on the number of launchers at the same time. High temperature spots which are the result of high velocity and high current density distributions end in intense destructive erosion. Decreasing intense erosion in electromagnetic launcher structures will be more economical and provide greater reliability, therefore resulting in more applications for EMLs especially commercial ones. In parallel electromagnetic launchers, these points and areas are not omissible. In cylindrical EMRLs the problem of high current density distributions and its consequent erosion is significantly decreased because of the uniform distribution of current in its symmetric structure.

Numerical simulation and analysis of the 3D transient muzzle flow field of underwater artillery

The in-depth study of the muzzle flow field contributes to the improvement of the gun and the design of the projectile. This study establishes an unsteady muzzle multiphase flow model of the underwater sealed launch with a three-dimensional scale. Among that, the VOF model is employed to trace the two-phase interface and the gas-liquid turbulent mixing is described by the standard k-ε turbulence model. Also, the established numerical model was validated by comparing underwater sealed launching experimental results. On this basis, numerical analysis on the muzzle flow field of the 30 mm artillery under different launching conditions were carried out by coupling with revised interior ballistic equations. The results show that the “necking” phenomenon occurs during gas-expansion process due to the interaction between water and projectile. Then, a “bowl-shaped” shock area is obviously formed at the muzzle. In addition, the Mach disk diameter and the corresponding growth rate are closely related to the projectile head cavitation diameter. The growth rate of Mach disk diameter increases with an increase of the cavitation diameter. When the muzzle velocities are different, the positions of the Mach disk formed are also different, presenting that the Mach disk is farther away from the muzzle with the increase of muzzle velocity.

FORENSIC ASPECTS OF THE STUDY OF BALLISTIC CHARACTERISTICS AND DAMAGING PROPERTIES OF LOW-SPEED KINETIC PROJECTILES

During unauthorized rallies, mass gatherings and riots with their extremist escalation into a confrontation with law enforcement agencies, the opposing side of the conflict, in order to remotely contain law enforcement officers and inflict maximum damage on them, actively uses improvised means and widespread objects (stones, fragments of building structures and materials, individual parts of various equipment, etc.), which can be put into free flight with the help of human muscle power or with the help of special throwing devices (slings, slingshots, etc.). Despite their relatively low muzzle velocity, such kinetic projectiles are capable of causing fairly severe bodily injury due to their mass. Since there are no methodological recommendations for determining the ballistic characteristics of these low-velocity kinetic projectiles in modern expert practice in weapons research, the authors conducted experimental studies to determine the data that can be used to calculate their trajectory parameters, as well as to determine their damaging properties.