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This paper presents the results of the theoretical external ballistic calculations for projectiles fired from barrels which correspond to the barrels used in two Polish small arms systems: MSBS- 5.56 system (MSBS GROT standard rifle and MSBS GROT carbine) and BERYL system (BERYL standard rifle and MINI BERYL carbine). The results obtained allowed the analyse of the effects of barrel length and the associated initial projectile velocity on the nature of projectile trajectory, particularly the over height and projectile range obtained along the trajectories. The analysis of the results facilitated an assessment of the scope of proposed changes in the settings of the firearm sights, resulting from the use of barrels of different lengths and the consequential changes in projectile trajectory.

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

The article is focused on the development of the underwater ballistic model of a supercavitating projectile fired from an underwater firearm. The supercavitating flows and their influences on the ballistic characteristics of the projectile are studied. The presented mathematical model is validated and experimentally verified for the supercavitating projectile of 5.7 mm in diameter fired from a smooth bore underwater rifle.

An experimental study and hydrocode simulation was conducted to investigate the correlation between hardness of steel and the ballistic performance of steel-encapsulated SiC armour modules against long rod impact. The armour module design composed of a SiC tile in confinement within 10 mm backing and 5 mm cover plates, which were made of AISI 4340 steel with varying hardnesses between HRC 30 to 50. The armour modules were subjected to normal impact by conical tungsten alloy long rods of 8.3 mm diameter and 115 mm length, at a nominal striking velocity of 1.25 km/s. A witness block of AISI 4340 steel was placed behind the armour module to capture the residual projectile. Failure analysis of the armour modules and the measurement of residual penetration in the witness blocks were applied to characterize ballistic performance of the ceramic armour modules. The different modes of failure of the backing plate and its influence on ballistic performance of the module were verified through visual inspection of test modules and analysis of high speed videos. Hydrocode simulation of the experiments using LS-DYNA was carried out to model the penetration and failure processes that occurred in the armour modules. The Johnson Cook model was applied in simulation of the steel confinement, accounting for the influence of hardness on JC model parameters. Results showed that increasing hardness of the backing enhanced the performance of the module while cover plate hardness had no influence within the range of hardnesses tested. This study paves the way for future studies to further understand the influence of steel hardness on the ballistics performance of steel-encapsulated silicon carbide (SiC) armour modules.

Exterior ballistics performance evaluation plays a critical role in the design and development of the electromagnetic railgun system. The ballistics performance evaluation can be regarded as a multicriteria decision-making problem, for the reason that various characteristics, also termed criteria, have effects on the overall performance. A sophisticated simulation model, including six-DOF mechanics, railgun configuration, environment, and aerodynamics models are established to compute the exterior ballistics profile. Then a comprehensive framework based on cloud model and analytic hierarchy process method are proposed to evaluate ballistics performance. Eight criteria including ballistics velocity, energy efficiency, flight time, flight range, overload, attack angle, and sideslip angle stability are selected to determine exterior ballistics performance. The proposed approach yields the certainty degree of each criterion and integrates multicriteria into the whole performance. Two scenarios including 32-MJ launch energy and 200-km strike range are taken to generate alternatives for assessing ballistics performance, which demonstrate the proposed approach is feasible. Results show that in the same launch energy 32 MJ, the performance levels of 12- and 16-kg projectiles are I (excellent) and III (medium), respectively. Besides, gaining the projectile’s mass can improve performance in the same strike range 200 km.

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.

Background: Methods for describing physics of impact and ballistics have been developed over a number of decades. These include analytical mathematical representations as well as modern computer simulations.

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.

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.

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.

The mechanisms of progressive penetration for two ultrahigh molecular weight polyethylene (UHMWPE) reinforced laminates have been investigated. One used an UHMWPE fiber reinforcement while the other utilized molecularly aligned tape. Both materials had similar out of plane compressive strengths, but the fiber system had a 40% higher in plane tensile strength than the tape. Laminated, 6 mm thick plates with a [0°/90°] ply architecture were impacted by a 12.7 mm diameter sphere under conditions that either allowed out of plane plate deflection or eliminated this deflection by rear support of the target. The depth of penetration and the ballistic limit in the rear-supported tests were identical for the two materials, and proceeded by progressive ply failure. However, tests in the edge clamped condition resulted in a substantially higher penetration resistance, especially for the higher tensile strength fiber-reinforced material. Edge clamped testing of a bilayer target, where the front third was composed of the tape material and the remainder comprised fiber reinforced laminate, had the same ballistic limit as a target composed of only the higher ply tensile strength fiber reinforced material. Penetration in both test support conditions was discovered to occur by tensile ply rupture under the projectile, consistent with a recently proposed mechanism for converting out of plane compression to in plane ply tension. Lateral displacement of plies was also observed near the sides of impact craters in both materials, indicating the existence of a second mechanism impeding penetration of the spherical shaped projectile.

The STANAG 4496 Ed. 1 Fragment Impact, Munitions Test Procedure is normally conducted by gun launching a projectile for attack against a munition. The purpose of this test is to assess the reaction of a munition impacted by a fragment. The test specifies a standardized projectile (fragment) with a standard test velocity of 2530±90 m/s. The standard test velocity can be challenging to achieve and has several loosely defined and undefined characteristics that can affect the test item response. MSIAC performed and international review of the STANAG 4496 related to the fragment impact test. To perform the review, MSIAC created a questionnaire in conjunction with the custodian of this STANAG and sent it to test centers. Fragment velocity variation, projectile tilt upon impact, aim point variation and projectile material were identified as observed gun testing issues. These, as well as other gun testing issues, have significant implications to resulting IM response.

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 kit contains two pairs of canards which can provide lift and despinning with a projectile for stability. An optimal design algorithm is developed to decide the profiles 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. The simulation and analysis results can be further applied to the exterior ballistics design.

Aiming at the object of the firing range maximization of the grenade of the cased telescoped ammunition(CTA) gun, a classical interior model was established according to the special charge structure of the CTA and the principle of the sequential combustion with two ignitions. Combined with the particle trajectory model, the optimization design of the integration of the interior and exterior ballistics was carried out using the intelligent optimization algorithm. The results show that, the maximum chamber pressure and the muzzle velocity simulated using the interior model of the CTA gun agree well with the experimental results. The optimal scheme of the projectile mass and the charge design was obtained by means of the optimization design of the ballistic integration. The grenade projectile mass increases 16.4% and the maximum range increases 11.8% compared with the original scheme. The method in the paper can improve the integrated ballistic performance of the CTA and provide an efficient tool for its ballistic and charge design.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. The effect of matrix shear strength on the ballistic response of simply-supported carbon fibre reinforced plastic (CFRP) beams was explored for a flat-ended projectile. To gain insight into the deformation and failure mechanisms, the following additional tests were performed on CFRP beams: (i) quasi-static indentation tests with rigid back support and, (ii) quasi-static cropping tests. In all 3 types of tests, CFRP [0°/90°] cross-ply laminates were tested in six states of cure, such that the matrix shear strength ranges from 0.1 MPa to 100 MPa. In the quasi-static cropping tests, the composite beams failed by shear plugging (involving transverse matrix cracks, ply delamination, and fibre fracture). In contrast, indirect tension (by ply tensile failure in the fibre direction) occurred in the back-supported quasi-static indentation tests. In the ballistic tests, the CFRP beams of high matrix shear strength (30 MPa–100 MPa) failed by a shear plugging mode. When the matrix shear strength was less than 30 MPa, the failure mode and the penetration velocity doubled and occurred by indirect tension. The optimal shear strength to give adequate static and ballistic strength is on the order of 20 MPa.

Monolithic, porous, thermal protection systems were used heavily on the Apollo command module, and they are currently being used on the next generation of US manned spacecraft, Orion. These systems insulate reentry critical components of a spacecraft against the intense thermal environments of atmospheric reentry. Additionally, these materials may be highly exposed to space environment hazards like solid particle impacts. This paper discusses impact studies up to 10 km/s on nominally 0.56 g/cm 3 Avcoat ablator with phenolic flexible hexcore. An impact model that describes projectile dispersion in a monolithic material is described that provides excellent agreement with observations over a broad range of impact velocities, obliquities and projectile materials.

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.

Radar is assumed to be tracking a cannon launched projectile travelling in a 2 dimensional drag environment. Extended Kalman Filter (EKF) is explored for the estimation of position and velocity of the projectile. Simulation is carried out using MATLAB and the results are presented. Finally, based on the results, EKF is recommended for tracking the projectile.

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.

With more than 1 trillion artificial objects smaller than 1 μm in low and geostationary Earth orbit, space assets are subject to the constant threat of space debris impact. These collisions occur at hypervelocity or speeds greater than 3 km/s. In order to characterize material behavior under this extreme event as well as study next-generation materials for space exploration, this paper presents a unique two-stage light-gas gun capable of replicating hypervelocity impacts. While a limited number of these types of facilities exist, they typically are extremely large and can be costly and dangerous to operate. The design presented in this paper is novel in two distinct ways. First, it does not use a form of combustion in the first stage. The projectile is accelerated from a pressure differential using air and inert gases (or purely inert gases), firing a projectile in a nominal range of 1–4 km/s. Second, the design is modular in that the first stage sits on a track sled and can be pulled back and used in itself to study lower speed impacts without any further modifications, with the first stage piston as the impactor. The modularity of the instrument allows the ability to investigate three orders of magnitude of impact velocities or between 101 and 103 m/s in a single, relatively small, cost effective instrument.

Three-dimensional FE model is presented for perforation under normal and oblique impact of sharp nosed projectiles on single and layered ductile targets. Numerical simulations have been carried out to study the behavior of Weldox 460 E steel and 1100-H12 aluminum targets impacted by conical and ogive nosed steel projectiles respectively. Weldox 460 E steel targets of 12 mm thickness in single and double layered combination (2 × 6 mm) and 1100-H12 aluminum targets of 1 mm thickness in single and double layered combination (2 × 0.5 mm) impacted at 0°, 15° and 30° obliquity were considered for simulations. The results of monolithic and layered targets were compared for each angle of impact. Monolithic targets were found to have higher ballistic resistance than that of the layered in-contact targets of equivalent thickness. Failure of both the targets occurred through ductile hole enlargement. However, ogive nosed projectile failed 1 mm thick aluminum target through petal formation and conical nosed projectile failed 12 mm thick steel target through a circular or elliptical hole enclosed by a bulge at rear surface. The explicit algorithm of ABAQUS finite element code was used to carry out the numerical simulations. Various parameters which play critical role in numerical simulation such as element size and its aspect ratio have been studied.

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...

An experimental study was made of the pressures generated by a single hydrodynamic ram event. A generic box type fuel tank simulator was fabricated to study the phenomenon and was capable of containing 3785.4 l of liquid thereby isolating the phases of the event from tank wall reflections, and enable separation of the effects of each phase. Tungsten, steel, and aluminum spherical projectiles were fired into the tank and the result was measured using high-speed pressure transducers, which were located throughout the tank, and compared to the pressure waves and events recorded inside the tank simulator with a high-speed video. It was determined that a high-pressure initial wave is generated at impact and is followed by the more gradual drag pressure around the projectile. The angular distribution of the initial wave and the variation with distance were investigated along with the effect of projectile mass on the drag pressure. This region of pressure decreases in the projectile wake, forming a trailing cavity that remains at a low pressure until the cavity begins to collapse. This results in the largest recorded pressure inside the simulator.

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.

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.

A new computational approach is developed to predict the impact behaviour of fabric panels based on the detailed response of the smallest repeating unit (unit cell) in the fabric. The unit cell is constructed and calibrated using measured geometrical (weave architecture, crimp, voids, etc.) and mechanical properties of the fabric. A pre-processor is developed to create a 3D finite element mesh of the unit cell using the measured fabric cross-sectional micro-images. To render an efficient method for simulation of multi-layer packs, these unit cells are replaced with orthotropic shell elements that have similar macroscopic (smeared) mechanical properties as the unit cell. The aim is to capture the essence of the response of a unit cell in a single representative shell element, which would replace the more complicated and numerically costly 3D solid model of the yarns in a crossover. The 3D finite element analysis of the unit cell is used to provide a baseline mechanical response for calibrating the constitutive model in the equivalent shell representation. This shell element takes advantage of a simple physics-based analytical relationship to predict the behaviour of the fabric's warp and weft yarns under general applied displacements in these directions. The analytical model is implemented in the commercial explicit finite element code, LS-DYNA, as a user material routine (UMAT) for shell elements. Layers of fabric constructed from these specialized elements are stacked together to create fabric targets that are then analysed under projectile impact. This approach provides an efficient numerical model for the dynamic analysis of multi-layer fabric structures while taking into account several geometrical and material attributes of the yarns and the fabric.

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.

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.

This paper presents the results of scale size experiments using a tungsten-alloy long-rod projectile fired against 97.5% Al2O3 ceramic targets at 1.8 and 2.6 km/s. Two targets were used, one having lateral steel confinement; the other without. The projectile overmatched the target, and residual projectile length and velocity were recorded using ballistic-syncro photography. Flash radiography was used during penetration of the unconfined target to obtain the penetration velocity. Manganin pressure gauges were also used to obtain additional data on the response of the ceramic target during penetration. Results from the eight experiments indicate that the confinement reduced the residual energy of the projectile at both impact velocities. Expressed in terms of the projectile impact energy, 55–56% was lost in the unconfined target at 2.6 km/s compared with 60% for the confined design. The same trend was found at 1.8 km/s with 68% and 72–73% for the unconfined and confined, respectively. Predictions using the QinetiQ GRIM2D hydrocode and a simplified form of the Johnson–Holmquist ceramic material model agreed well with the experiments for three out of the four test configurations. The predicted projectile erosion and retardation against the confined target at 1.8 km/s was excessively high. Analytical predictions using the Tate modified Bernoulli equation also gave reasonably accurate predictions for three of the tests, but values for the Tate target ‘strength’ extracted from experiments using a different target configuration were not accurate for the target design used in this paper. r 2006 Elsevier Ltd. All rights reserved.

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 .

Terminal ballistics deals with interactions between targets and projectiles. One of the areas of interest is wound ballistics, where one studies the interaction between a projectile (a bullet or a fragment) and the human body. Soap and gelatin are commonly used materials for simulating soft human body tissue in wound ballistics experiments. They are to be considered as tools for comparing the effectiveness of different projectiles. The department of weapon systems & ballistics of the Belgian Royal Military Academy is examining to what extent the Autodyn hydrocode can be used as a numeric tool for simulating the penetration of military bullets into ballistic soap. This article presents the philosophy and the results of the prcject's first phase i.e. the use of Autodyn for simulating the penetration of a steel sphere into a block of ballistic soap as a result of a normal impact at different velocities. A series of experiments (real firings) have been performed in the laboratory of the department. They serve as a reference and validation tool for the numerical approach. The latter is characterized by the specific problem of accurate material modeling of the soap. The application of a stepwise parametric study of material models and parameters has resulted in numerical simulations which fit quite well with experiments.

This paper describes the design of an 8-MJ base-pushed launch package for railgun launch. Extensive interior ballistics and flight dynamic analyses were performed. The launch package was designed to withstand a peak acceleration of 57 k-gees, and a substantial amount of lateral load. The lateral load was of prime importance for this launch package to ensure survivability of subprojectile joints present inside. Even though the launch was by a base-push method, a sabot was necessary to carry the bore-riders. Sabot separation dynamics and projectile aerodynamic coefficients were evaluated to ensure a successful flight. The package was successfully tested at the 32-MJ UK EM Gun Facility located at Kirkcudbright, Scotland at 7-MJ muzzle energy.

At our university, students in introductory physics classes perform a laboratory exercise to measure the range of a projectile fired at an assigned angle. A set of photogates is used to determine the initial velocity of the projectile (the launch velocity). We noticed a systematic deviation between the experimentally measured range and the range calculated using the speed as determined by the photogates. In this paper, we will discuss the origin of this systematic error and derive a simple formula to correct it. In particular, we find that the launch speed given by our instrument is significantly different from the actual launch speed of our projectile.

There has long been a need to understand the impact response of explosive materials, and continual improvements result from the design of careful, well-instrumented experiments. This article summarizes details of the design and construction of a laboratory facility capable of launching projectiles at explosive targets at velocities up to 1500 m s−1. There are two types of experiment that are required. In the first, a gun launches a plate of great planarity at an equally flat target. This geometry is known as plate impact and a target loaded in this manner experiences a state of one-dimensional strain. This loading is accomplished by launching plane impactors onto targets aligned to micron tolerances, normal to the impact axis to less than 0.5 mrad of tilt. In the second, it is required to attain the ability to recover impacted explosive targets that have been loaded in one-dimensional strain for subsequent microstructural assessment. The development of this capability will be described in a subsequent pub...

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 physical and chemical phenomena involved in the ballistic process, both in conventional guns and in electrothermal-chemical (ETC) guns, are very complex, so that optimization of gun performance requires a detailed understanding of the influence of different parameters. The initial stage of propellant ignition is critical to the rest of the process, in terms of both performance (muzzle velocity, repeatability) and safety. A better understanding of the ignition stage is thus very important in achieving improved performance. In this paper, we propose a new method and ignition sensor aimed at providing direct experimental information about the propellant ignition process. We further report on measurements of the ignition delays, and the propagation of the "ignition wave", performed using these sensors in experimental devices such as closed bombs and gun simulators.

Microdebris particles generated by hypervelocity impacts between complex projectiles and ballistic missile targets can affect sensitive components of such aerospace systems. Current models assume an isotropic dispersion of this microdebris about the postimpact debris cloud center of mass. Data collected from recent tests indicate that a nonisotropic microdebris dispersion model is needed. The results are presented of a study aimed at improving the capabilities of an existing model that characterizes the microdebris environment created in a high-speed impact. Following a review of test data collection techniques, a nonisotropic microdebris dispersion model is developed as a series of modifications to the existing microdebris size distribution model. Relevant test data are then used to evaluate the proposed nonisotropic model. It is found that the modified model is more correct in accounting for the microdebris fragment population created in a high-speed impact than the current isotropic dispersion model.

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.

While toy hunting at a local department store, I came upon a reasonably priced, interesting toy airplane that flies in a circle and drops a toy bomb. With some modifications this toy can be used in an exciting and highly motivating projectile-motion experiment with good results.

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.