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The penetration of projectiles into semi-infinite targets helps in the understanding and modelling of terminal ballistics. The article describes field test results of 5.56×45 mm F1 Ball and 7.62×51 mm M80 Ball ammunition. The targets were 25-mm-thick mild and high strength steel plates of Grade 250 MPa and 350 MPa, respectively. The tests recorded penetration depth, muzzle and impact velocities, and bullet mass. Despite its smaller calibre, the 5.56 mm × 45 mm F1 Ball ammunition recorded deeper penetrations than the larger calibre 7.62 mm × 51 mm M80 Ball ammunition. This is due to the 5.56 mm ammunition comprising a hardened steel penetrator and lead core, whereas the 7.62 mm ammunition comprised only a lead core. Multiple shots were fired for each type of munition. The coefficient of variation of steel penetration is approximately 0.10 and 0.03 for 5.56 mm and 7.62 mm rounds, respectively. The article also presents predictive models of steel penetration depth and compares these to the field test results.

The ballistics equations for spherical pellets in free flight are simplified through appropriate scaling of the pellet velocity and pellet distance. Two different drag coefficient curves are averaged to yield a single curve applicable to shot pellets and round balls. The resulting S-shaped drag coefficient curve is approximated by three straight-line segments. The scaled ballistics equations are then solved exactly and simple formulas are found for the velocity and flight time with respect to trajectory distance. The formulas are applicable to spherical shot pellets and round balls of any composition under any atmospheric conditions. The formulas are amenable to quick and easy computation and may also serve as an aid in understanding and comparing black-box ballistics calculators. For shotshell ballistics, an important assumption in the present investigation is that the pellets are moving as single, free spheres and not as a dense cloud or in a shot column, in particular, the pellets are not interacting during flight. Therefore, the formulas are most appropriate for single round balls, for large shot sizes, and for pellets of small shot size fired from open chokes. The formulas are clear and accessible, and can be implemented by military or law enforcement personnel as well as hunters and shooters. This work differs from previous investigations in that accurate ballistics formulas are derived for spherical projectiles of shotguns and muzzleloaders using realistic drag coefficients.

In support for the development of a new small-arm ballistic computer based on the NATO Armaments Ballistic Kernel (NABK) for the Canadian snipers, DRDC Valcartier Research Centre was asked to carry out high-fidelity 6 degree-of-freedom (6-DOF) trajectory simulations for a set of relevant vignettes for the snipers, and to compare the direct fire 6-DOF simulation results with those obtained with the 4-DOF NATO Armaments Ballistic Kernel (NABK) adapted to simulate small-arm ammunition trajectories. To conduct this study, DRDC Valcartier Research Centre used BALCO v1.0b. This paper presents (1) the process and the methodology employed to carry out the sniper direct fire solution study, (2) the modeling and the simulation of the sniper projectile, the approach used in calculating the firing solutions, and the results of direct fire simulations for the sniper vignettes, and (3) an analysis of firing solutions obtained with the BALCO engine versus those of NABK. The work presented in this paper serves to validate the use of NABK for the new sniper ballistic computer.

An optimization method is introduced to design the aerodynamic parameters of a dual-spin two-dimensional guided projectile with the canards for trajectory correction. The nose guidance component contains two pairs of canards which can provide lift and despin with the projectile for stability. The optimal design algorithm is developed to decide the profiles both of the steering and spinning canards, and their deflection angles are also simulated to meet the needs of trajectory correction capabilities. Finally, the aerodynamic efficiency of the specific canards is discussed according to the CFD simulations. Results that obtained here can be further applied to the exterior ballistics design.

This study evaluates and compares the accuracies of five different ballistic models in predicting the speed profile of a supersonic bullet using radar measured speed data for 36 types of bullets. Each of the five ballistic models is parameterised by a ballistic constant and the muzzle speed of the bullet. In practice, each of these two parameters spans a wide range of values because of the large number of different bullet types that are available for use in a variety of applications. For a given bullet type, the bullet's ballistic constant and muzzle speed are determined by fitting the ballistic model to the data in a least-squares (LS) sense, and the root-mean-square (RMS) and maximum absolute (MA) deviations of the LS fit of the model from the data are computed. The best ballistic model (out of the five) is the one that has the smallest RMS and MA errors for the maximum number of bullet types. This ballistic model has been applied to accurate ranging of small arms fire using a single sensor node, with and without a priori knowledge of the model parameters, and its effectiveness for both cases is demonstrated using real data recorded from a field experiment.

Ballistics is the study of a projectiles motion and can be broken down into four stages: internal, intermediate, external and terminal ballistics. The study of the effects a projectile has on a living tissue is referred to as wound ballistics and falls within terminal ballistics. To understand the effects a projectile has on living tissues the mechanisms of wounding need to be understood. These include the permanent and temporary cavities, energy, yawing, tumbling and fragmenting. Much ballistics research has been conducted including using cadavers, animal models and simulants such as ballistics ordnance gelatine. Further research is being conducted into developing anatomical, 3D, experimental and computational models. However, these models need to accurately represent the human body and its heterogeneous nature which involves understanding the biomechanical properties of the different tissues and organs. Further research is needed to accurately represent the human tissues with simulants and is slowly being conducted.

Effective structural design to resist ballistic effects such as small arms or fragmenting weapons has been a goal since weapons were developed. Approaches currently in use for ballistic design are predominantly deterministic and allow designers to decide what wall thickness should be used to stop a prescribed projectile impacting at a predefined velocity. The research presented in this paper provides a framework for conducting reliability analysis of structures subjected to bullet and fragment demands. Thus, pseudo-fragility curves are developed for the limit states related to spall and perforation of wall panels, residual velocities of bullets and fragments, and injury to personnel. The pseudo-fragility analysis provides engineers and owners with a tool to quickly assess the reliability of a wall system subjected to high velocity, low mass projectiles. In particular, the proposed analysis method allows designers and owners to determine the probability of spall and perforation, residual velocity, ...

The fundamental components of any meteoroid/orbital debris (MOD) risk assessment calculation are environment models, damage response predictor equations, and failure criteria. In the case of a spacecraft operating in low earth orbit, the response predictor equation typically takes the form of a ballistic limit equation (BLE) that defines the threshold particle sizes that cause failure of a spacecraft wall or component. Spacecraft risk assessments often call for BLEs for spacecraft components that do not exist. In such cases, it is a common procedure to use an existing BLE after first equivalencing the actual materials and/or wall thicknesses to the materials that were used in the development of the existing BLE. The question naturally arises regarding how close are the predictions of such an ‘adapted BLE’ to the response characteristics of the actual materials/wall configurations under high speed projectile impacts. This paper presents the results of a study that compared the predictions of a commonly used BLE when adapted to the Soyuz OM wall configuration against those of a new BLE that was developed specifically for that Soyuz wall configuration. It was found that the critical projectile diameters predicted by the new Soyuz OM wall BLE can exceed those predicted by the adapted use of the existing BLE by as much as 50% of the existing BLE values. Thus, using the adapted version of the existing BLE in this particular case would contribute to a more conservative value of assessed risk. If the same trends were to hold true for other spacecraft wall configurations, then it is also possible that using existing BLEs, even after they have been adjusted for differences in materials, etc., may result in predictions of smaller critical diameters (i.e., increased assessed risk) than would using BLEs purposely developed for actual spacecraft configurations of interest.

As part of a research program, it was desired to better understand the impact of the rotating chamber alignment with the barrel throat on the precision and accuracy of a novel cased telescoped (CT) ammunition firing rifle. In order to perform the study, a baseline CT ammunition chamber which was concentric with a Mann barrel bore was manufactured. Additionally, six chambers were manufactured with an offset relative to the barrel bore. These chambers were used to simulate a misaligned chamber relative to the bore axis. Precision and accuracy tests were then performed at 200 m in an indoor range under controlled conditions. For this project, 5.56 mm CT ammunition was used. As the chamber axis offset relative to the gun bore was increased, the mean point of impact was displaced away from the target center. The shift in the impact location is explained by the presence of in-bore yaw which results in lateral throw-off and aerodynamic jump components. The linear theory of ballistics is used to establish a relationship between the chamber misalignment and the resulting projectile mean point of impact for a rifle developed to fire CT ammunition. This relationship allows for the prediction of the mean point of impact given a chamber misalignment.

A laboratory gun that uses compressed gas as its propellant was designed and tested for the study of small projectiles traveling in soils with initial velocities ranging from 50 to 200 m/s. The gun employed the use of air or helium with an electrically triggered, pneumatically piloted, solenoid valve. The triggering system was designed to provide remote activation. A photo gate speedometer was utilized to measure the exit velocity of each projectile. Details of the electro-pneumatic control system are presented in this paper along with the design of the gun assembly and its subsystems. The effects of different design parameters, including muzzle length, projectile mass, propellant type, and volume of compressed gas utilized, on projectile velocity were investigated. Statistical analysis of the gun performance is presented. The gun is currently being used to visualize the fundamental physics of rapid earth penetration in soils, using transparent soils.

Abrasion collar is usually described as a feature of bullet entry wounds caused by friction and indentation. The present case is that of the peculiar entry wound caused by a piece of flying shrapnel which was ejected from a furnace in a steel plant. The scrap metal which exploded in the plant was sourced from the West Asia region. The entry wound on the chest was circular and had an abrasion collar around it. The projectile was a cylindrical object of obscure origin. The forensic science laboratory put forth the possibility that the projectile was a component of an artillery fuze. A decades old study which employed high-speed photography has rejected the possibility that abrasion collars are produced by friction. High-velocity projectiles other than bullets can also produce abrasion collars as the rubbing of the bullet against the skin or its rotation are not the causative mechanisms.

Instead of the capillary plasma generator (CPG), a discharge rod plasma generator (DRPG) is used in the 30 mm electrothermal-chemical (ETC) gun to improve the ignition uniformity of the solid propellant. An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun (2D-IB-SPETCG) is presented to describe the process of the ETC launch. Both calculated pressure and projectile muzzle velocity accord well with the experimental results. The feasibility of the 2D-IB-SPETCG model is proved. Depending on the experimental data and initial parameters, detailed distribution of the ballistics parameters can be simulated. With the distribution of pressure and temperature of the gas phase and the propellant, the influence of plasma during the ignition process can be analyzed. Because of the radial flowing plasma, the propellant in the area of the DRPG is ignited within 0.01 ms, while all propellant in the chamber is ignited within 0.09 ms. The radial ignition delay time is much less than the axial delay time. During the ignition process, the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech. The radial ignition uniformity is proved. The temperature of the gas increases from several thousand K (conventional ignition) to several ten thousand K (plasma ignition). Compare the distribution of the density and temperature of the gas, we know that low density and high temperature gas appears near the exits of the DRPG, while high density and low temperature gas appears at the wall near the breech. The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch. The 2D-IB-SPETC model can be used for prediction and improvement of experiments.

Knowledge of impact conditions is critical to evaluating the terminal impact performance of a projectile. For a small caliber bullet, in-flight velocity has been precisely measured for decades using detection screens, but accurately quantifying the orientation of the bullet on a target has been more challenging. This report introduces the Automated Small-Arms Photogrammetry (ASAP) analysis method used to measure, model, and predict the orientation of a small caliber bullet before reaching an impact surface. ASAP uses advanced hardware developed by Sydor Technologies to record a series of infrared digital photographs. Individual images (four orthogonal pairs) are processed using computer vision algorithms to quantify the orientation of the projectile and re-project its precise position and orientation into a three-dimensional muzzle-fixed coordinate system. An epicyclic motion model is fit to the measured data, and the epicyclic motion is extrapolated to the target location. Analysis results are fairly immediate and may be reviewed during testing. Prove-out demonstrations have shown that the impact-angle prediction capability is less than six hundredths of a degree for the 5.56 mm ball round tested. Keywords: Yaw, Terminal ballistics, Exterior ballistics, Test & evaluation, Computer vision, Image processing, Angle of attack

Determination of ballistic performance of an armor solution is a complicated task and evolved significantly with the application of finite element methods (FEM) in this research field. The traditional armor design studies performed with FEM requires sophisticated procedures and intensive computational effort, therefore simpler and accurate numerical approaches are always worthwhile to decrease armor development time. This study aims to apply a hybrid method using FEM simulation and artificial neural network (ANN) analysis to approximate ballistic limit thickness for armor steels. To achieve this objective, a predictive model based on the artificial neural networks is developed to determine ballistic resistance of high hardness armor steels against 7.62 mm armor piercing ammunition. In this methodology, the FEM simulations are used to create training cases for Multilayer Perceptron (MLP) three layer networks. In order to validate FE simulation methodology, ballistic shot tests on 20 mm thickness target were performed according to standard Stanag 4569. Afterwards, the successfully trained ANN(s) is used to predict the ballistic limit thickness of 500 HB high hardness steel armor. Results show that even with limited number of data, FEM-ANN approach can be used to predict ballistic penetration depth with adequate accuracy. Copyright (C) 2015, China Ordnance Society. Production and hosting by Elsevier B.V. All rights reserved.

Hunting shot are 1.2-10 mm diameter balls, usually made of lead alloys, forming a cluster projectile used in smoothbore hunting shotguns. Shot may also be used in pistol and revolver ammunition, in which it can constitute structural element of the projectile. Shot pellets may also be made of other materials and have other shapes. The aim of this paper is to aggregate information on the topic available from a number of different sources. It is hoped that such information will be useful for forensic ballistics experts. Historical development of pellets and their manufacturing technology from the 15th century is presented.Śrut myśliwski to kulki o średnicy 1,2–10 mm wykonane zwykle ze stopów ołowiu, które stanowią pocisk mnogi w gładkolufowej myśliwskiej broni palnej. Ładunek śrutu może znajdować się także w amunicji pistoletowej lub rewolwerowej, w której może stanowić element konstrukcyjny pocisków. Śrucina może być również wykonana z innych materiałów i przybierać inne kształty. Celem pracy było zebranie rozproszonych informacji na ten temat, bardzo przydatnych m.in. dla specjalistów zajmujących się balistyką sądową. Przedstawiono zarys historyczny rozwoju śrutu oraz technologię jego produkcji, począwszy od XV wieku.

The deflection of projectile nose is aimed at changing the motion of the projectile in flight with the theory of motion control and changing the exterior ballistics so as to change its range and increase its accuracy. The law of external ballistics with the deflectable nose is considered as the basis of the design of a flight control system and an important part in the process of projectile development. Based on the existing rigid external ballistic model, this paper establishes an external ballistic calculation model for deflectable nose projectile and further establishes the solving programs accordingly. Different angle of attack, velocity, coefficients of lift, resistance, and moment under the deflection can be obtained in this paper based on the previous experiments and emulation researches. In the end, the author pointed out the laws on the impaction of external ballistic trajectory by the deflection of nose of the missile.

Wind can and often does significantly affect impact-point prediction (IPP) performance for thrusting/ballistic endoatmospheric projectiles. Wind exacerbates the estimation ambiguity between drag and thrust in the dynamic model and induces additional uncertainty in the IPP procedure. A tracker accounting for the wind effect is presented and simulation study shows that it can be fully compensated if the wind information is available. An-point adaptive initialization based on a goodness-of-fit test and a statistical significance test is introduced. Based on the multiple interacting multiple model (MIMM) approach developed recently, the IPP performance is investigated with respect to the total observation time and the sensor accuracy in various wind scenarios. In each Monte Carlo (MC) run of the simulation study, under the same sensor accuracy and the same observation time, the same set of random numbers has been used (but different in different MC runs) for the same caliber projectile in various wind scenarios to examine how much the wind affects the IPP performance with/without the exact knowledge of the wind information. The final conclusion is that with the wind effect accounted for, the IPP performance in the presence of wind is practically the same as in its absence.

As illustrated in literature, ballistics is a branch of theoretical mechanics, which studies the construction and working principles of firearms and ammunition, their effects, as well as the motions of projectiles and bullets 1 . Criminalistics identification, as part of judiciary identification represents an activity aimed at finding common traits of different objects, objectives, phenomena and beings, but more importantly, traits that differentiate each of them from similar ones 2-4 . In judicial ballistics, in the case of rifled firearms it is relatively simple for experts to identify the used weapon from traces left on the projectile, as the rifling of the barrel leaves imprints on the bullet, which remain approximately identical even after the respective weapon is fired 100 times with the same barrel. However, in the case of smoothbore firearms, their identification becomes much more complicated. As the firing cap suffers alterations from being hit by the firing pin, determination of the force generated during impact creates the premises for determining the type of firearm used to shoot the respective cartridge. The present paper proposes a simple impact model that can be used to evaluate the force generated by the firing pin during its impact with the firing cap. The present research clearly showed that each rifle, by the combination of the three investigated parameters (impact force maximum value, its variation diagram, and impact time) leave a unique trace. Application of such a method in ballistics can create the perspectives for formulating clear conclusions that eliminate possible judicial errors in this field.

In firearm examiners’ and forensic specialists’ casework as well as in air gun proof testing, reliable measurement of the weapon’s muzzle velocity is indispensable. While there are standardized and generally accepted procedures for testing the performance of air guns, the method of seating the diabolo pellets deeper into the breech of break barrel spring-piston air guns has not found its way into standardized test procedures. The influence of pellet seating on the external ballistic parameters was investigated using ten different break barrel spring-piston air guns. Test shots were performed with the diabolo pellets seated 2 mm deeper into the breech using a pellet seater. The results were then compared to reference shots with conventionally loaded diabolo pellets. Projectile velocity was measured with a high-precision redundant ballistic speed measurement system. In eight out of ten weapons, the muzzle energy increased significantly when the pellet seater was used. The average increase in kinetic energy was 31 % (range 9–96 %). To conclude, seating the pellet even slightly deeper into the breech of spring-piston air guns might significantly alter the muzzle energy. Therefore, it is strongly recommended that this effect is taken into account when accurate and reliable measurements of air gun muzzle velocity are necessary.

The use of cartridge projectiles in the ballistic evaluation of armor can result in measurement uncertainty if there is variability in their construction. This report details a method that was developed to batch analyze and compare the volumes of (210) BS41 surrogate projectiles that were scanned using X-ray computed tomography. The method described automatically segments and obtains the axial-symmetric radii profiles of components contained within the projectile (outer jacket, inner jacket, core), which can then be used to quantify and compare projectiles to one another numerically using a root-mean-square-error calculation. Projectiles are then grouped together according to the similarity of their components. Also discussed is graphical-cluster analysis of the projectiles, which aids in understanding the source of their variability as well as an approach to use this methods numerical component values to account for projectile variability in the ballistic evaluation of armor.

This report relates to the discovery and development by the authors of armor designs using certain elastomers applied as coatings to the front side of rigid substrates, to increase the ballistic and blast performance of armor. This has led to much activity intended to optimize and exploit the technology for various applications, both military and civilian. Since armor improvements of even a few percent are substantial, quantifying the performance of armor materials requires high accuracy. Herein we describe test methods and analyses useful in achieving measurements of sufficient quality. Since the optimal design of any armor, conventional or advanced, depends on the threat (i.e., the nature of the projectile and its mass and energy; single- versus multiple-hit defeat), we describe how performance attributes can be quantified and valid comparisons made between different armor designs.

Whipple shields were first proposed as a means of protecting spacecraft from the impact of micrometeoroids in 1947 [1] and are currently in use as micrometeoroid and orbital debris shields on modern spacecraft. In the intervening years, the function of the thin bumper used to shatter or melt threatening particles has been augmented and enhanced by the use of various types and configurations of intermediate layers of various materials. All shield designs serve to minimize the threat of a spall failure or perforation of the main wall of the spacecraft as a result of the impact of the fragments. With increasing use of Whipple shields, various ballistic limit equations (BLEs) for guiding the design and estimating the performance of shield systems have been developed. Perhaps the best known and most used are the "new" modified Cour-Palais (Christiansen) equations [2]. These equations address the three phases of impact: (1) ballistic ( 7 km/s), where the projectile melts or vaporizes at impact. The performance of Whipple shields and the adequacy of the BLEs have been examined for the first two phases using the results of impact tests obtained from two-stage, light-gas gun test firings. Shield performance and the adequacy of the BLEs has not been evaluated in the melt/vaporization phase until now because of the limitations of launchers used to accelerate projectiles with controlled properties to velocities above 7.5 km/s. A three-stage, light-gas gun, developed at the University of Dayton Research Institute (UDRI) [3], is capable of launching small, aluminum spheres to velocities above 9 km/s. This launcher was used to evaluate the ballistic performance of two Whipple shield systems, various thermal protection system materials, and other spacecraft-related materials to the impact of 1.6-mm- to 2.6-mm-diameter, 2017-T4 aluminum spheres at impact velocities ranging from 8.91 km/s to 9.28 km/s. Test results, details of the shield systems, and nominal ballistic limits for the two Whipple shields are shown in Figures 1 and 2.

This paper presents a multiple model procedure to estimate the state of a ballistic object in the atmosphere and identify it using radar measurements for the purpose of impact point prediction (IPP). A key aspect of the projectile identification is the identification of the mode of stabilization used, i.e., fin stabilization or spin stabilization. Measurements are taken during the first part of its trajectory up to apogee, and the final state estimate obtained by the multiple model estimator is then predicted to its impact point on Earth. For each model a different extended Kalman filter (EKF) is used for state estimation, and the model likelihoods are then used to identify the projectile. It is shown from simulations carried out on three fin-stabilized projectile trajectories (mortars of different caliber) and a spin-stabilized (howitzer) projectile trajectory that the projectile can be identified with a high probability and also that the impact point is predicted to a high degree of accuracy and with a consistent covariance. It is also shown that accurate modeling of the gyroscopic effect caused by the spinning of the howitzer projectiles is critical for IPP accuracy in the case of spin-stabilized projectiles. The key in the design of the multiple model filter (MMF) is the choice of the models, which based on the characteristics of the different projectile trajectories, have different state dimensions. A choice has to be made between too few state components, which leads to poor accuracy/consistency, and too many state components, in which case the accuracy and discrimination ability suffers because of too much uncertainty in the model.

The design of a canard-controlled mortar projectile using a bank-to-turn concept is presented. A unique feature of this smart mortar configuration is that it is equipped with a set of two reciprocating fixed-angle maneuver canards and a set of two reciprocating fixed-angle roll canards. An active control system is designed such that the roll canards set the body in the proper maneuver plane and the maneuver canards extend to perform trajectory corrections. Example results and Monte Carlo simulations demonstrate control system effectiveness in reducing dispersion error due to launch perturbations and winds. Comparison studies with a rolling airframe equipped with reciprocating maneuver canards show that the bank-to-turn approach offers more control authority, eliminates problematic angle-of-attack oscillations, and requires lower-bandwidth actuators.

Problem statement: Future generations of intelligent munitions will use Microelectromechanical Systems (MEMS) for guidance, fuzing logic and assessment of the battlefield environment. The temperatures fund in a gun system, however, are sufficient to damage some materials used in the fabrication of MEMS. The motivation of this study is to model the dynamic temperature distribution in a typical small-caliber projectile. Approach: An axisymmetric finite-element model of a projectile is developed to simulate temperatures through internal ballistics (the projectile is in the gun barrel) and external ballistics (the projectile travels in a free trajectory towards the target). Accuracy of the simulation is confirmed through comparison to analytical models and to payloads attached to experimental projectiles. In the simulation, the exact values for some boundary conditions are unknown and/or unknowable. A sensitivity analysis determines the effect of these uncertain parameters. Results: The simulation shows that friction at the projectile-gun barrel interface is primarily responsible for elevated temperatures in a gun system. Other factors have much smaller effects. The short duration of the internal ballistics prevents the frictional heat from diffusing into the bulk of the projectile. As a result, the projectile has a shallow, high-temperature zone at its bearing surface as it leaves the gun barrel. During external ballistics, this heat will diffuse through the projectile, but most of the projectile experiences temperatures of 56°C or lower. Simulation shows that the polymer package around a MEMS device will further attenuate heat flow, limiting temperatures in the device to less than 30°C. Conclusion: The finite element model demonstrates that a MEMS device may be engineered to survive temperatures expected in the ballistic environment.

Uncontained aircraft engine failure can cause catastrophic damaging effects to aircraft systems if not addressed in the aircraft design. Mitigating the damaging effects of uncontained engine failure and improving the numerical modeling capability of these uncontained engine events are crucial. In this paper, high strain rate material behavior of one of the most extensively used materials in the aircraft industry is simulated and the results are compared against ballistic impact tests. Ballistic limits are evaluated by utilizing explicit finite-element (FE) simulations based on the corresponding ballistic impact experiments performed at different material thicknesses. LS-DYNA is used as a nonlinear explicit dynamics FE code for the simulations. A Johnson–Cook material model with different sets of parameters is employed as a thermo-viscoplastic material model coupled with a nonlinear equation of state and an accumulated damage evaluation algorithm for the numerical simulations. Predictive performance of the...

Laminated ballistic composite panels are an important part of hard-plate protective body armour and may be subjected to a wide variety of impact conditions depending on the projectile, impact velocity and armour construction, to name a few. The ballistic response of laminated composite panels has been investigated through direct impacts of two non-deforming projectiles (7.5 mm diameter hardened steel 120° cylindrical–conical, and 9 mm hemispherical nosed) selected to enhance different failure mechanisms including penetration and delamination. Experimental and numerical studies were carried out to determine the ballistic response of laminated Kevlar® 29 and 129 composite panels, commonly used in protective body armour. These panels were impacted at velocities between 130 and 250 m/s, which were below the penetration limit of the panels. A numerical parametric study was initially undertaken to determine those material properties which reduce back face signature (BFS; maximum dynamic displacement), one of the important performance indicators for assessing personal protection. Experimental material characterization then allowed mechanical property data to be determined for numerical simulations, which showed good agreement with the experimental data, particularly for the conical projectile impacts on both types of Kevlar® panels. Numerical simulations of the impact tests accurately predicted the BFS and dynamic response for the conical projectile impacts, while the BFS for the hemispherical projectiles was slightly low. This can be attributed to the dominant delamination failure mechanisms, which may not be completely captured by the numerical model. Importantly, the numerical analysis accurately predicted the initial velocity of the panel back face for the hemispherical projectiles and the time to reach maximum BFS for the conical projectiles.

When a shotgun or rifle is fired, the shooter experiences an impact to the upper body known as recoil. This force felt by the shooter is a consequence of the momentum transfer from the accelerating ballistic charge to the firearm, which is ultimately transferred to the shooter as he/she restrains the firearm's induced motion. The accelerating ballistic charge responsible for the recoil has two components. The first is the acceleration of the projectile itself. The recoil associated with this action is known as primary recoil. The second component is associated with the acceleration of the gases created by the combustion of the gunpowder propellant. For competitors in the shooting sports, gun recoil can affect performance and create discomfort. An objective method of measuring felt recoil forces would be useful to evaluate methods of recoil reduction. An experimental test apparatus was developed to measure recoil forces of sporting rifles and shotguns. No modifications to the firearms themselves were necessary to make the measurements. Through both inertial and dissipative restraint mechanisms, the apparatus reproduced gun movement that was representative of that experienced by a particular shooter. This should result in measured recoil forces similar to those experienced by the shooter. The apparatus measures the horizontal shoulder force and the vertical force component exerted at the stock comb. The recoil event was found to be quite short, having duration on the order of 10 ms. Peak recoil forces for common shotgun target loads were in the range of 1.6-2.2 kN (360-494 lbf). The apparatus was found sensitive enough to measure recoil force differences among different factory loaded ammunition, and differences in recoil force imparted by different firearms shooting the same ammunition. The apparatus should prove useful for quantifying differences in felt recoil as affected by ammunition type, gunstock geometry, barrel porting, recoil reduction devices, and gun weight, among other factors.

The present paper constructs a rigid–plastic model to assess the effect of a soft nose on the perforation of metallic plates struck by a stubby projectile. A low-density nose-cabin-column, i.e., an assembly of seeker and guidance/control unit, is installed in the front of a real missile. It usually acts as an energy absorber and buffer in the perforation of metallic plates and notably affects the terminal results of projectile. The problem is equivalent to a blunt rigid projectile with a soft nose perforating a circular metallic plate. Effects of transverse shear, bending and membrane deformations on the perforation process are included in a rigid–plastic analysis. Especially the effect of an ahead structural response, induced by the soft nose impacting the target plate, is considered in the model. Analytical formulae for the ballistic performance are obtained for a range of plate thicknesses, which agree well with available experimental results.

In the past, the presence of textile fibres in the bullet track of gunshot injuries in body regions covered with clothes was used to differentiate between entrance and exit wounds; as with handguns, a displacement of textile fibres was considered possible only in the direction of the shot. In the present study, the transfer of textile fibres from the entrance and exit regions into the bullet path was systematically investigated with the help of a skin-gelatine composite model. For this purpose, the skin of the bullet entrance and exit region was covered with textile fabric (jeans or jersey material), before conducting four test series of ten test shots each firing a 9-mm Parabellum full-jacketed projectile from a distance of 2 m. The length of the bullet track was 25 and 8 cm, respectively. Subsequently, the bullet tracks were microscopically investigated in sections for the presence of textile fibres. In all the investigated bullet tracks, textile fibres both from the entrance and exit regions could be demonstrated. The distribution pattern depended on the length of the bullet path and the extension of the temporary cavitation. The results are discussed in relation to the relevant literature.

This paper presents the results of a series of experimental tests, aimed at investigating the impact and dynamic response of a volcanic shelter. Similar shelters are to be installed in the Stromboli island (Aeolian archipelago, Sicily, Italy), to protect human lives from the pyroclastic eruptions of the volcano. Basically, the Shelter consists of two homologous reinforced concrete shells, interconnected by rubber-based special devices, which absorb and dissipate most of the impact energy. The Shelter has been specifically designed to resist, without damage, an impact with a 150 kg mass rock, knocking the surface of the external shell at 62.5 m/s speed. The experimental tests were carried out on a 1:2-scale model, using a testing apparatus purposely realised to simulate impact conditions comparable with those considered in the design. Impact energy and mass ratio between projectile and reinforced concrete shell were assumed as main experimental parameters and varied during the tests. A finite element model of the Shelter was also implemented and direct-integration time-history analyses were performed, to validate the experimental results. Reference to the Hertz's law was made to simulate the impact between the two bodies. The experimental tests proved the ability of the Shelter to resist impacts without damage. Acceptable agreement between numerical predictions and experimental results was found.

The aim of this work is to develop a methodology for the evaluation of the ballistic requirements of a helicopter component. The situation studied in the work refers to the possibility of a damaged helicopter performing an emergency manoeuvre and a 30-min return flight after the impact of a 7.62 NATO projectile on a shaft of the tail rotor transmission. The paper describes the finite element methodology adopted to simulate the impact of the projectile on the shaft, and outlines the hypotheses on which this methodology is based. The numerical simulation of the propagation of the crack originating from the damage caused by the impact is also described. It is thus possible to determine the time required to reach failure of the shaft. The effect of the residual stresses on the residual life of the shaft is studied in detail.

Current gun technology uses solid propellants that consist of small geometrically similar grains which are ignited by a primer. Propellant burn characteristics are determined by a combination of the chemical propellant itself and grain geometry. The ballistic characteristics of a preformed cartridge cannot be changed in real time. Thus, varying applications require the use of different projectiles, propellants, and launch systems.

A minimal control law is designed for a canard controlled smart projectile. This system allows for an envelope of down and cross range targeting capability for a set initial firing state. The controller relies on limited aerodynamic data with initial firing conditions in order to avoid the need for complicated electronics and sensors. First range and lateral control are shown to be achieved independently, and then they were combined to demonstrate full 3D control. A 6DoF simulation is used to show the effectiveness of the proposed algorithm. Sensitivity analysis to variations in initial conditions are carried out using Monte Carlo simulations. With a 5 m/s muzzle velocity, a 95% confidence predefined target landing is achieved with −0.236%±0.792% lateral and −0.352%±0.185% range error.

An efficient method was needed to perform ballistic testing using 0.30-cal. Fragment Simulating Projectiles at or near subsonic velocity in order to screen new resin systems for advanced composite/ceramic armor scaled-down test coupons. This technical note outlines the custom gun system and testing methods developed to enable this ballistic testing.

Deflection nose is a new concept of fast response control mode, partial nose of projectile can deflect certain angle relative to the axis of projectile body and pressure difference emerges in the windward and leeward side of warhead then generates aerodynamic control force, and this control way has high control efficiency and very good application prospect in the ammunition system. Nose deflection actuator based on smart material and structure makes projectile body morphing then obtains additional aerodynamic force and moment, changes the aerodynamic characteristics in the projectile flight process, produces the corresponding balance angle, sideslip angle then resulting in motor overload, adjusts flight moving posture and controls the ballistics, finally realizes shooting range changing and improves firing accuracy. In order to study characteristics of self-adaptive control projectile, numerical simulations were conducted by fluid dynamics software ANSYS FLUENT for fin stabilized rocket projectile. Computed aerodynamics on different nose delectation angle, different Mach number and different angle of attack, and compared the aerodynamic characteristics with the different nose deflection angles. Results show that the nose deflection control has bigger influence on the head of rocket projectile, and caused asymmetry of the flow field structure, make the warhead differential pressure in the windward and leeward surface increases, resulting in a larger lift. Finally, ballistics experiments were done for verification. Results can offer theoretical basis for self-adaptive rocket projectile design and optimization also provides new ideas and methods for field smart ammunition research.

Ballistic limit curves (BLCs) for dual- or multi-wall spacecraft wall systems impacted by spherical projectiles exist for a variety of impact conditions. However, meteoroids and orbital debris particles can take any shape, and non-spherical projectiles can be more damaging than equal mass spherical projectiles under the same impact conditions. In a recent study, a series of BLCs for a typical dual-wall configuration impacted by a variety of non-spherical projectiles were developed and presented in terms of equivalent spherical projectile diameter as a function of impact velocity. In order to be more consistent with debris environment predictions and to be useful for spacecraft design, such BLCs need to be drawn in units that are consistent with environment flux models used in that design process. In this paper, we have recast the equivalent spherical projectile diameter BLCs and now present them using radar cross-section (RCS) diameter as the characteristic length parameter. The recast BLCs are seen to be more tightly grouped and are not as spread out as they were when plotted using equivalent spherical projectile diameter. Thus, the effect of projectile shape on penetrating ability is shown to be somewhat reduced when considering characteristic length as the size parameter as opposed to an equivalent mass diameter.

The ability to destroy the key assets of an enemy is an important goal of an attacking force and requires an agile and adaptable military capability effective against a number of very different threats. In ballistics, this contributes to an interest in moving to higher projectile velocities to benefit from the potential to increase the range of a projectile. It also generates an interest in the study of the benefits of increased kinetic energy that can be delivered to a target. The paper describes the work to produce a projectile design solution under certain constraints but with an impact velocity of about 2 km s −1 , good in-bore and in-flight stability and acceptable retardation at the target. The paper shows that a projectile with these characteristics was achieved with a projectile mass of 8.1 kg. The second phase of the research programme was concerned with building a hollow aluminium carrier shell. The paper describes the research to assess the integrity and stability of the projectile under gun launch conditions, to demonstrate acceptable dispersion and impact yaw at the target and to demonstrate a minimum impact velocity of 2.1 km s −1 .

The Walker–Anderson and Ravid–Bodner analytical models for penetration of projectiles in metallic plates are well known in the ballistics community. The Walker–Anderson model uses the centerline momentum balance in the projectile and target to calculate the penetration history into a semi-infinite medium, while the Ravid–Bodner model uses the upper bound theorem of plasticity theory modified to include dynamic effects. The Ravid–Bodner model also includes a rich selection of failure modes suitable for finite-thick metallic targets. In this paper a blended model is presented: momentum balance is used to calculate the semi-infinite portion penetration (before the back of the target plate begins to flow), and the Ravid–Bodner failure modes are used to determine projectile perforation. In addition, the model has been extended to handle multiple plate impact. Numerical simulations show that after target failure the projectile still continues to erode for some microseconds. This time has been estimated and incorporated into the model. Examples are presented for long-rod projectiles against thick and spaced-plate targets backed by a witness pack that is separated from the main target element(s) by an air gap. Agreement with results from numerical simulations is quite good.

The article of record as published may be found at http://dx.doi.org/10.1520/JTE20130136 High-speed video has been used by ballistics engineers as a cost-effective technique to measure the spin-rates of both spin-stabilized and fin-stabilized artillery projectiles. Often at test ranges, state-of-the-art video systems are used to verify critical launch events following muzzle exit. From manual analysis of these videos, important performance metrics such as velocity, pitch angle, and spin-rate can be estimated. To do this, operators step through the video frames and record the time at which certain fiducial markings or numbered stripes are observed on the projectile as it rotates. The different methods evaluated in this paper are automated processes for calculating the muzzle-exit spin-rate from launch videos of spin-stabilized artillery projectiles painted with stripes. Image processing and computer vision techniques are employed to segment the shape of the projectile and extract the stripe pattern in each video frame. The most accurate algorithm estimates are validated to within 0.02 % for both laboratory and computer-simulated flight video and within 0.13 % for manual analysis of real flight video. The sensitivities of the methods to image resolution, video frame-rate, and the length of flight captured are evaluated. Areas of continued research and recommendations for increasing the accuracy of measurements in future tests are also identified.

The U.S. Army Research Laboratory conducted a study to examine the effects of a small caliber (7.62-mm) cartridge s spit-hole on the interior ballistic performance of the cartridge. The performance metrics evaluated were cartridge pressure and muzzle velocity. The laboratory incorporated its custom breech apparatus that measures primer pocket pressure, and used standard midcase pressure measurements and high-speed imaging to evaluate early projectile motion out of a custom-built short barrel gun.

On the battlefield, it is well known that the target effects using artillery systems diminish exponentially with the number of rounds fired at a particular target. To maximize target effects, rounds must be designed to hit a target with a minimum number of rounds that impact the target in rapid succession. The modern science of the exterior ballistics has evolved as a specialized branch of the dynamics of rigid bodies, moving under the influence of gravitational and aerodynamic forces and moments. The six degrees of freedom (6-DOF) simulation flight dynamics model is applied for the accurate prediction of short and long-range trajectories of high and low fin spin-stabilized projectiles and small bullets. Variable coefficients of aerodynamic forces, moments and Magnus effects are taken into account depending on Mach number and total angle of attack variations. The above analysis is compared to the modified linear modified simulation model for rapid trajectory predictions and high accuracy impact point computations for constant and variable aerodynamic coefficients is also applied for the accurate prediction of short and long range trajectories. The computational results of the proposed synthesized analysis give satisfactory agreement with other technical data and recognized exterior atmospheric projectile flight investigations. The variable modified atmospheric flight model can be further coupled to a suitable trajectory tracking control system for current and future control actions applied to projectiles for minimizing the estimated error to target impact area. Epicyclic motion and gyroscopic stability analysis are also examined for spinning and non-spinning projectiles. A new engineering correlation is proposed for the flat-fire disturbance due to aerodynamic jump performance firing at different angles which relative to the helicopter’s flight path motion. The computational results of the generalized aerodynamic jump formula are verified compared to McCoy’s recognized simulation modelling.

Orleans University, France;Samara State Aerospace University, Russia, 5th International Conference on Mechanical and Aerospace Engineering, ICMAE 2014 -- 18 July 2014 through 19 July 2014 -- Madrid -- 107490, In this study, dynamic analysis of carbon plain weave square plates with different damage patterns including pattern of post-low velocity impact and patterns of post-ballistic impact is considered. For this purpose, vibration tests are performed to present the vibration characteristics of the four-edge clamped square plates. Effects of bullet-tip geometry, projectile velocity and impact damage location on the vibration characteristics are examined experimentally. Results are given in graphical form. © (2014) Trans Tech Publications, Switzerland.

A simple extension of the standard linear theory, describing the free-flight motion of a projectile, now includes the influences due to the projectile impacting yaw cards. The card impacts are modeled as ideal delta function impulses that are shown to alter the usual yawing motion of a spin-stabilized projectile passing through a yaw card range. Card-induced changes in the complex-valued yaw modes are expressed as difference equations. Known analytic solutions to these difference equations show how card impacts influence a projectile's yawing motion by relating simple expressions of the card spacing to a parameter describing the material density of the yaw cards. These solutions also reveal that both bounded and unbounded yaw mode magnitudes can be induced by yaw card impacts. Furthermore, the model shows that moments caused by repeated projectile and card interactions should not always be treated as negligible. Examples of these results for a typical small arms projectile (7.62 mm) launched from an unworn gun tube are presented.

The use of telemetry in gun-launched projectiles is not as common as in missile and aircraft systems. A primary reason is the launch environment of guns. Conventional solid propellant guns often produce launch accelerations approaching 100,000 g's. Additionally, if the bore is rifled, large lateral accelerations are also produced. Recently, the Hardened Subminiature Telemetry and Sensor System (HSTSS) program has developed and demonstrated a series of telemetry products and technologies specifically designed to make gun-launched in-bore and flight measurements more routine and affordable. This paper reviews the products and flight experiences from the HSTSS program and addresses the potential use of the HSTSS products and techniques for use on projectiles launched from electromagnetic rail guns.

The state-of-the-art in gun projectile technology has been used for the aerodynamic stabilisation.This approach is acceptable for guided and controlled rockets but the free-flight rockets suffer fromunacceptable dispersion. Sabot projectiles with both spin and fms developed during the last decadeneed careful analysis. In this study, the second method of Liapunov has been used to develop stability criterion for a projectile to be designed with small fins and is made to spin in the flight. This criterion is useful for the designer.

Summary Investigations are conducted at ISL on new hypervelocity launchers to fulfill requirements in different fields of ballistics such as launching dynamics, aeroballistics, terminal ballistics, aerothermodynamics, and supersonic combustion studies. One objective considered is to determine the operational conditions to accelerate a 90mm-caliber projectile with a mass of ~1.5kg to a velocity of 3km/s while keeping the acceleration level below 40,000g. This moderate level of acceleration is required to investigate at high velocities models that are fragile because of their design and/or their onboard opto-electronical equipments. A means to fulfill these velocity and acceleration requirements is ram-accelerator technology. This paper presents research conducted at ISL with smooth-bore ram-accelerators in the thermally choked propulsion mode. Therefore, two accelerators in calibers 30 and 90mm respectively, operated within the launch room of the aeroballistic range facility are described. Experimental results are presented describing the two-fold strategy followed to achieve the maximum performance, i.e., optimization of the projectile configuration and optimization of the combustible gas mixtures. To date a maximum velocity of about 1985m/s has been achieved with the 90mm accelerator (projectile mass = 1.34kg, ram-section length 16.2m, injection velocity in the ram-section 1330m/s) and 2380m/s with the 30mm accelerator (projectile mass 68.6g, ram-section length 9m, injection velocity in the ram-section = 1380m/s). Potential applications of ram-accelerators for ballistic studies are discussed and performances compared to those of conventional launchers that are currently used at ISL for ballistic studies. Finally, very first preliminary experiments are presented describing the acceleration of high l/d rods using a ram-accelerator.

Medical literature abounds with reports on injuries and fatalities caused by airgun projectiles. While round balls or diabolo pellets have been the standard projectiles for airguns for decades, today, there are a large number of different airgun projectiles available. A very uncommon — and until now unique — discarding sabot airgun projectile (Sussex Sabo Bullet) was introduced into the market in the 1980s. The projectile, available in 0.177 (4.5 mm) and 0.22 (5.5 mm) caliber, consists of a plastic sabot cup surrounding a subcaliber copper-coated lead projectile in typical bullet shape. Following the typical principle of a discarding sabot projectile, the lightweight sabot is supposed to quickly loose velocity and to fall to the ground downrange while the bullet continues on target. These sabot-loaded projectiles are of special forensic interest due to their non-traceability and ballistic parameters. Therefore, it is the aim of this work to investigate the ballistic performance of these sabot airgun projectiles by high-speed video analyses and by measurement of the kinetic parameters of the projectile parts by a transient recording system as well as observing their physical features after being fired. While the sabot principle worked properly in high-energy airguns (E > 17 J), separation of the core projectile from the sabot cup was also observed when discharged in low-energy airguns (E