Gun Firing Research Articles

Devising a technique for descending the illumination elements of aerial vehicles

The object of this study is the process of descending illumination elements equipped with a braking device in the form of two-bladed grills rotating in different directions. The classic parachute method does not provide the necessary speed of descent, it has low illumination parameters and significant drift of illumination elements by side wind. To solve the tasks set, mathematical dependences were obtained for calculating the aerodynamic characteristics of the descent device with the illumination element and its delivery to the ejection point. The drag and lift force coefficients during the flow around the blades of a dual-rotor impeller with different Reynolds numbers were determined by the method of numerical modeling based on the ANSYS CFX software package. The optimal geometric characteristics of the profile satisfying the condition for the necessary speed of descent of the illumination element at the given weight of the descent apparatus were determined. Reasonable requirements for illumination parameters and an improved composition of the flare have been proposed. A mathematical model of the movement of a body of variable mass to the point of ejection of the illumination element was built. The new design of the descent device makes it possible to reduce the speed of descent by 10–15 % and increase the weight of the payload by 20–30 %. The proposed illumination composition provides sufficient illumination of the object for 5 minutes with a light intensity of 2–2,5 million candelas and an average diameter of the illuminated area of 2000–2500 m. The mathematical model of the movement of a variable mass body to the point of the illumination element ejection makes it possible to determine with high accuracy the gun firing settings with illumination ammunition (30–40 % more accurate) and the time of ejection of illumination elements. Results of the current research make it possible to solve the scientific problem of ensuring the maximum efficiency of illuminating the terrain at night

Simulation and experimental results of plasma opening switch operation with inductive and electron beam diode loads in different plasma regimes

This paper reports the experimental results of a plasma opening switch (POS) that operates at hydrogen and carbon plasma regimes confirmed based on the conduction bipolar limit of the plasma species and the availability of plasma species during the conduction based on the density profiles. The generator is the compact capacitor bank developed using the synchronization of four field distortion spark gap switches. The plasma source is coaxial cable plasma guns characterized using the Faraday cup plasma diagnostic. The experimental results are compared with the time domain simulation code in which the POS is represented as the dynamic resistance governed by the physical equations of the bipolar model. The experiments and simulations are compared for inductive load and dynamic load of accelerating gap of 5 mm between the anode and cathode at the load end. From the results, POS can be operated based on the availability of plasma species with proper synchronized triggering between the plasma gun firing and generator firing that can operate at low and high values of currents.

Study on the influence of helicopter rotor flow on projectile motion

In this paper, the muzzle flow field generated during helicopter gun firing is numerically studied. Based on Navier-Stokes equation and Standard k − ε turbulence model, the projectile motion is realized by using overlapping mesh technology. The development of the muzzle flow field formed by complex wave systems such as Mach disk and shock wave under the influence of helicopter rotor flow at different speeds, as well as the force and motion state of the projectile in the flow field are analysed. The results show that the degree of asymmetry of the flow field, the force and offset of the projectile are positively correlated with the rotor flow velocity. The research will help to improve the understanding of the muzzle flow field of helicopter gun and provide a new idea for improving the firing accuracy of helicopter gun..

Study of seat dynamics under transient strong impact load

The turret seat ring assumes an important load transfer role in the gun firing process, and its stiffness has a great influence on the muzzle vibration response. Based on the basic theory of nonlinear finite element method, this paper establishes a high-precision refined finite element analysis model of the seat ring based on the contact and collision between the ring and the steel ball, the steel ball and the fixed ring, and the fitting gap between the steel ball and the ring and the fixed ring, and characterizes the equivalent stiffness of the seat ring by its axial equivalent stiffness, radial equivalent stiffness and overturning equivalent stiffness. The dynamic response is obtained by simulation. The results show that the axial equivalent stiffness, radial equivalent stiffness and overturning equivalent stiffness of the seat ring are non-linear in a certain load range, and the equivalent stiffness changes linearly and steadily with the increase of load, and fluctuates in a small range.

Effect of ignition delay runaway of traveling charge on gun firing safety

In order to promote the engineering application of dense traveling charge technology, a structure scheme of dense traveling charge with central hole was proposed. Aiming at this scheme, the interior ballistic model was established, and the interior ballistic performance advantages of the new traveling charge scheme and the effect of inconsistent ignition delay time on the interior ballistic performance were analysed. The calculated results show that the central hole combustion traveling charge scheme is a feasible scheme. Compared with the end face burning traveling charge scheme, the burning rate of the traveling charge is reduced and the mass ratio of the traveling charge to the total charge is increased, which can effectively increase the muzzle velocity of the projectile and improve the performance of the gun. While the control precision of ignition delay time is at 0.01ms level, which puts forward higher requirements for the design and processing of the slow-burning layer. The ignition delay runaway of the traveling charge will have great influence on the interior ballistic performance of the gun, especially if the delay time is too small, it will cause premature ignition and combustion of traveling charge, resulting in high secondary pressure peak, which is not conducive to the safety of artillery launch. This study can provide guidance for the design of delayed ignition mechanism of traveling charge based on slow burning material.

Research on Error Transfer Model and Simulation of Aircraft Gun Structure

In order to study the influence of structural motion and geometric error on the firing density during the firing of the aircraft gun, based on the multi-body dynamics theory, the structural topology of the aircraft gun was established, and the motion error coordinate relationship was constructed by the firing chain and the support chain of the aircraft gun. Establish motion transformation matrix and error transformation matrix between adjacent volumes. Further, the error transfer model of the aircraft gun firing process is constructed. The transmission law of the muzzle offset error caused during the firing of the aircraft gun is revealed. Then the model is simulated and analyzed, and the parameters such as test position error, motion error and muzzle vibration displacement under different firing rates are identified. Finally, the simulation results are compared with the experimental test results. The results show that the average error rate in the azimuth direction is 3.94%, and the average error rate in the pitch direction is 6.86%. The error rate in the pitch direction is significantly higher than that in the azimuth direction, and the measured offset values are higher than the simulated values, which verifies the validity and correctness of the model. It can meet the engineering design requirements and provide the basis for the structural design and optimization of the aircraft gun.

Study on Damage Effectiveness of Single Projectile of Small Caliber Anti-aircraft Gun Under Multi-error Constraints

In this paper, the damage effectiveness of a single projectile of small caliber (30-35 mm) anti-aircraft gun under multi-error constraints is studied. Based on the known prior information of target motion and the dispersion mathematical model of prefabricated fragment warhead, under the constraints of fragment effective killing radius and target equivalent size, the fuze starting characteristic factor is introduced to establish the integrated model of fuze and warhead. Based on the Monte-Carlo method, the variation law of the damage effectiveness of a single projectile under the joint constraints of the gun firing angle error and the fuze fixed range error is analyzed. The simulated annealing (SA) algorithm is used to find the global optimal solution of the model. The optimal damage effectiveness of a single projectile under multi-error constraints is found. The results show that the damage effectiveness of single projectile is increased by 26.91% without changing the state of existing weapon and equipment.

Fatigue life prediction of aircraft gun cabin structure under impact

The aircraft gun firing will cause serious impact on airframe structure. According to the gun firing principle, the muzzle blast wave is simulated by chemical explosion. ALE method is used to deal with the fluid-structure interaction between high-pressure flowing air and the surface of the cabin. Then the expression model of the impact load is established. The numerical calculation is completed to analyse the dynamic response of the cabin structure under the impact load. The parameters of load and cabin model are modified by using the experiment results. Comparing the calculated dynamic response with the experiment results, the error is within acceptable range. Multiaxial stress equivalence and rain-flow counting method are used to process the simulation impact response data to estimate the impact fatigue life. In conclusion, the paper provides a feasible method for analysing dynamic response and fatigue life of gun cabin structure.

Flight Control Law for Stabilizing Transient Response of the Aircraft during Gun Firing

Highly maneuverable fighter aircraft are equipped with various weapons including a gun firing system for successful air-to-air and air-to-ground missions. In the gun firing system, the muzzle is usually positioned at an offset from the centerline of the aircraft to facilitate maintainability and accessibility on the ground, to ensure the pilot’s visibility, and to avoid vibrations. However, this mounting position causes the repulsive force for gun firing to generate a moment around the center of gravity and distorts the aircraft’s attitude, degrading the accuracy of the target point. In this paper, we propose the application of an additional augmentation control method, as a hybrid INDI control, that combines model- and sensor-based incremental nonlinear dynamic inversion (INDI) controls to minimize the maximum overshoot of transient response of the aircraft during gun firing. As a result of the frequency- and time-domain evaluation, the additional augmentation control can effectively reduce the transient response during gun firing. In addition, this control method is more robust against uncertainties, and its structure is simple compared to the conventional open-loop type gun compensation control since it does not require any gain scheduling according to flight conditions.

Research on the Dynamic Characteristics of a Low Recoil Swing Chamber Gun Based on the Cased Telescoped Ammunition and Rarefaction Wave Gun Technology

Based on the theory of a low-recoil rarefaction wave(RAVEN)gun firing cased telescoped ammunition(CTA), the equation system of interior ballistics and kinematics also dynamics were established. The dynamic characteristic curves were obtained by numerical simulation analysis, and the results were verified by firing tests. Compared with traditional closed-breech guns, the low recoil force swing chamber gun keeps the projectile’s muzzle velocity basically unchanged, while the maximum recoil is reduced by up to 74%. Based on these results, the parameters of the inertial breech buffer spring were optimized by numerical simulation optimization algorithms which efficiency is faster than using virtual prototyping technology, while the maximum recoil force of the breech reduced by 14.2% without affecting system performance and structural installation size, which effectively improved the overall performance of the weapon system.

Simulation Research of rigid chain failure in a modular gunpowder delivery machine

Based on the theory of a low-recoil rarefaction wave (RAVEN) gun firing cased telescoped ammunition (CTA), the models of interior ballistics and dynamics were established. The dynamic characteristic curves were obtained by numerical simulation analysis, and the results were verified by firing tests. Compared with traditional closed-breech guns, the low recoil force swing chamber gun keeps the projectile’s muzzle velocity basically unchanged, while the maximum recoil is reduced by up to 74%. Based on these results, the parameters of the inertial breech buffer spring were optimized while the maximum recoil force of the breech reduced by 14.2% without affecting system performance and structural installation size, which effectively improved the overall performance of the weapon system.

Development of a shooting strategy to neutralize UAV swarms based on multi-shot cooperation

Economical and efficient assault methods using drones and drone swarms severely assailed the defenders during the conflict in the Middle East. In view of the current situation, based on medium and large-caliber anti-aircraft artillery platforms, this article analyzes and calculates the advantages of using multiple anti-aircraft guns against drones, the threat of a drone colony, and the drone colony density. Additionally, this study determines the firing sequence of a drone swarm, and provides anti-aircraft gun firing position points to reduce the firing cost and increase the efficiency. This ensures the optimization of an air defense system within a short duration of time. Ammunition is an effective defense against drone swarms. The experimental results demonstrate that compared with that of the conventional methods of individually shooting the swarms, this strategy can simultaneously neutralize multiple targets, assign shooting tasks to multiple artillery guns, and can cause greater damage to a drone swarm.

Sea Fall Point Measurement Method Based on Cone Angle Intersection

The naval gun strikes against the sea need to measure the deviation of the fall point to determine the accuracy and hit probability. In order to improve the accuracy of measuring the fall point position of the naval gun, this paper proposes a maritime fall point measurement method based on cone angle intersection, which does not need to use the axis angle data of the equipment and eliminates the dependence on the equipment’s axis angle data when measuring accuracy. Firstly, the photographic measurement method is used to achieve automatic optical intersection of single equipment at different moments, using two observation stations and one cooperative target ship. Then, the image data within 10 km from the measured target are collected using two observation stations. The line of sight directions and angles of the two observation stations are combined to measure the target object and the cooperative target ship at each observation station. The constraint of the approximate equal radius of the Earth ellipsoid is added under close range conditions. The cone angle intersection model mapping relationship is established. Finally, the coordinate position of the target object in three-dimensional space is calculated using field tests at sea and compared with the actual position for analysis.The experimental results show that the measured fall point is within 5 m in the range of 700 m with a ratio of more than 75%. This has increased the range of measurement accuracy processing and proved the feasibility of the measurement method. The method can be used for calibrating large and medium caliber naval gun firing to the sea to improve the firing accuracy of the weapon. It has guiding significance for measuring the fall point position of naval guns at sea.

Chemistry and lung toxicity of particulate matter emitted from firearms

Smoke emissions produced by firearms contain hazardous chemicals, but little is known if their properties change depending on firearm and ammunition type and whether such changes affect toxicity outcomes. Pulmonary toxicity was assessed in mice exposed by oropharyngeal aspiration to six different types of smoke-related particulate matter (PM) samples; (1) handgun PM, (2) rifle PM, (3) copper (Cu) particles (a surrogate for Cu in the rifle PM) with and without the Cu chelator penicillamine, (4) water-soluble components of the rifle PM, (5) soluble components with removal of metal ions, and (6) insoluble components of the rifle PM. Gun firing smoke PM was in the respirable size range but the chemical composition varied with high levels of Pb in the handgun and Cu in the rifle smoke. The handgun PM did not induce appreciable lung toxicity at 4 and 24 h post-exposure while the rifle PM significantly increased lung inflammation and reduced lung function. The same levels of pure Cu particles alone and the soluble components from the rifle fire PM increased neutrophil numbers but did not cause appreciable cellular damage or lung function changes when compared to the negative (saline) control. Penicillamine treated rifle PM or Cu, slightly reduced lung inflammation and injury but did not improve the lung function decrements. Chelation of the soluble metal ions from the rifle fire PM neutralized the lung toxicity while the insoluble components induced the lung toxicity to the same degree as the rifle PM. The results show that different firearm types can generate contrasting chemical spectra in their emissions and that the rifle PM effects were mostly driven by water-insoluble components containing high levels of Cu. These findings provide better knowledge of hazardous substances in gun firing smoke and their potential toxicological profile.

Water Column Detection Method at Impact Point Based on Improved YOLOv4 Algorithm

For a long time, the water column at the impact point of a naval gun firing at the sea has mainly depended on manual detection methods for locating, which has problems such as low accuracy, subjectivity and inefficiency. In order to solve the above problems, this paper proposes a water column detection method based on an improved you-only-look-once version 4 (YOLOv4) algorithm. Firstly, the method detects the sea antenna through the Hoffman line detection method to constrain the sensitive area in the current detection image so as to improve the accuracy of water column detection; secondly, density-based spatial clustering of applications with noise (DBSCAN) + K-means clustering algorithm is used to obtain a better prior bounding box, which is input into the YOLOv4 network to improve the positioning accuracy of the water column; finally, the convolutional block attention module (CBAM) is added in the PANet structure to improve the detection accuracy of the water column. The experimental results show that the above algorithm can effectively improve the detection accuracy and positioning accuracy of the water column at the impact point.

Revision of ANSI S12.7 methods for measurements of Impulse Noise

ANSI S12.7 Methods For Measurements Of Impulse Noise 1986 (R2006) applies to all kinds of impulsive noise, whether discrete event sources, such as quarry and mining explosions or sonic booms, or from multiple event sources such as pile drivers, riveting, nail guns, or rifle or gun firing. The working has been working on proposed changes to the measurement methods, especially high speed digital waveform recording techniques to improve the accuracy of capturing the peak of the waveform as well as the details of the structure. The presentation will describe the proposed changes to the measurement methods and measurement microphones as well as the applications of the revised standard once it is approved.

Solenoid Coil and Capacitor Design to Improve the Performance of Multi-Stage Coil Guns

The purpose of this study was to design capacitors and a coil, which are components of an electric circuit, for improved performance of multi-stage electromagnetic coil guns. The electromagnetic force generated in the solenoid coil is determined by the magnitude of the current, supplied from the capacitor to the solenoid coil. Since the current flowing in the solenoid coil is not constant, the variability of electromagnetic force becomes larger. Design variables such as the capacitor capacity, coil winding, and firing distance are complicatedly related and determine the coil gun firing rate together. This study sets the number of turns of the solenoid coil, capacitor capacity, and firing distance as design variables for a five-stage coil gun. The electric circuit configuration of the coil gun with the highest velocity in each firing stage, was derived through the design of experiments. The coil gun’s finite element analysis model was constructed using ANSYS Maxwell, an electromagnetic analysis program, and implemented through a transient simulation to calculate the projectile’s velocity. Additionally, a prototype was manufactured based on the derived results to conduct launch experiments, and the experimental and simulation results were compared.

Projectile Explosion Position Parameters Data Fusion Calculation and Measurement Method Based on Distributed Multi-Acoustic Sensor Arrays

In conventional weapon test field, the parameter of projectile explosion position is an important index to measure the control ability and damage efficiency of fuze. Due to the random deviation of gun firing and the difference of detection performance of fuze itself, the projectile explosion position is uncertain and relatively scattered in terminal ballistic, which is easy to miss the projectile explosion information. In order to obtain the parameters of projectile explosion position in large area of in terminal ballistic, this paper constructs a projectile explosion position testing system with distributed multiple acoustic sensor basic arrays, establishes the calculation model of projectile explosion position by a basic array, researches a multi-source data fusion algorithm based on the measurement data of multiple array acoustic basic arrays and gets real projectile explosion coordinates. To improve the measurement accuracy, we use the wavelet transform filtering method to filter the output signal of the acoustic sensors, and propose the time extraction algorithm of the projectile explosion acoustic signal with the wavelet modulus maximum. Through experiment and analysis, we collect the sound signal of the actual projectile explosion and verify the rationality and correctness of the proposed calculation model and algorithm.

Numerical Simulation and Analysis of Muzzle Flow During a Rarefaction Wave Gun Firing

AbstractRarefaction wave gun can significantly reduce the recoil and the barrel heat without affecting projectile velocity during the launching process. This paper aims to improve the understanding of the muzzle flow characteristics during a rarefaction wave gun firing and clarify the different ballistic behaviors between the rarefaction wave gun and the traditional gun. First, the mathematical models and the numerical methods of the muzzle flow with the interior ballistic process were established. Then, the numerical simulation results were compared with the experimental data to validate the reliability and accuracy. Next, the rarefaction wave propagation behavior was described, and the interior ballistic process of the rarefaction wave gun was compared with that of the traditional gun. Then the development law of the muzzle flow field for the rarefaction wave gun coupled with the interior ballistics process was studied. Finally, the different detailed results of the muzzle flow between the traditional gun and the rarefaction wave gun were investigated. The development processes of the muzzle flow in both guns are generally similar, but the strength of the main flow parameters and the ballistic performances for the rarefaction wave gun are smaller than that for the traditional gun due to the rarefaction wave influence. This paper could provide a valuable reference for the research and design on the rarefaction wave gun.

Data Collection, Modeling, and Classification for Gunshot and Gunshot-like Audio Events: A Case Study.

Distinguishing between a dangerous audio event like a gun firing and other non-life-threatening events, such as a plastic bag bursting, can mean the difference between life and death and, therefore, the necessary and unnecessary deployment of public safety personnel. Sounds generated by plastic bag explosions are often confused with real gunshot sounds, by either humans or computer algorithms. As a case study, the research reported in this paper offers insight into sounds of plastic bag explosions and gunshots. An experimental study in this research reveals that a deep learning-based classification model trained with a popular urban sound dataset containing gunshot sounds cannot distinguish plastic bag pop sounds from gunshot sounds. This study further shows that the same deep learning model, if trained with a dataset containing plastic pop sounds, can effectively detect the non-life-threatening sounds. For this purpose, first, a collection of plastic bag-popping sounds was recorded in different environments with varying parameters, such as plastic bag size and distance from the recording microphones. The audio clips’ duration ranged from 400 ms to 600 ms. This collection of data was then used, together with a gunshot sound dataset, to train a classification model based on a convolutional neural network (CNN) to differentiate life-threatening gunshot events from non-life-threatening plastic bag explosion events. A comparison between two feature extraction methods, the Mel-frequency cepstral coefficients (MFCC) and Mel-spectrograms, was also done. Experimental studies conducted in this research show that once the plastic bag pop sounds are injected into model training, the CNN classification model performs well in distinguishing actual gunshot sounds from plastic bag sounds.