Showing papers on "Projectile published in 1995"

Wound ballistics and the scientific background

Abstract: Introduction. Physical Basics of Wound Ballistics. Preliminary Remarks. Frames of Reference and Systems of Units, Notation. Mechanics. Kinematics. Mass, linear momentum, force. Work and energy. Circular motion. The laws of conservation. Equations of motion. Fluid Dynamics. General. Thermodynamic principles. Material properties. Inviscid flows. Viscid flows. Jets. Measurement Techniques. General. Dynamic processes. Physical quantities. Measurement technique to detect the development of rapidly changing pressures. Historical Background and International Treaties. The Development of Small Arms. General. The development of ammunition. The development of small arms. The twentieth century. International treaties. Early Developments in Wound Ballistics. Ammunition and Arms, Ballistics. General. Ammunition. The different parts of a cartridge. Ammunition. Recent developments of ammunition. Firearms. Composition and classification of firearms. Hand guns. Rifles. Ballistics. General. Interior ballistics. Processes at the muzzle. Exterior ballistics. Stability and tractability. General Wound Ballistics. General. Preliminary remarks. What does a human being die of after being hit? Possible causes of death. Definition of various energy quantities, their derivation and relationship. Processes in the Shooting Channel (Especially the Temporary Cavity). General. Behaviour of projectiles in a dense medium. Phenomenology of the temporary cavity. Quantitative description of the temporary cavity. Instability of a projectile in a dense medium and the consequences on the temporary cavity. Sectional density influence on the shape of the temporary cavity. The behaviour of different projectiles designs in a target medium. On the sterility of projectiles. Tissue Simulants. General. Gelatine. Soap. Comparison: soap-gelatine. Tissue simulant for bones. Other Simulation Methods. Corpses. Experiments on animals. Mathematical models, computer models. Cell cultures. Wound Ballistics of Handgun Ammunition. Penetration Depth and Perforation Capacity of Projectiles in Gelatine, Soap, Muscle Tissue and Bones. General theory. Penetration depth in gelatine, soap and muscle tissue. Penetration capacity in bones. Threshold velocities of the eye. On the Effectiveness of Projectiles. General. Criteria of effectiveness. Measured values for energy release of projectiles in gelatine. Is it possible to establish a general criterion of the effect? Special Projectiles. General. Non-penetrating projectiles. Projectiles with Extraordinary ballistics qualities. Fluid jets and gas jets as projectiles. Wound Ballistics of Rifle Ammunition. General. Remote Effects. General. Shock waves. Pressure waves in blood vessels. Bone fractures in the vicinity of the shooting channel. Debridement. General. The relationship between the size of the temporary cavity and the amount of devitalized tissue. Determination of the Effectiveness of Rifle Bullets and Fragments - Casualty Criterion. General. Casualty criterion. Bases for the Formulation of Future International Treaties. Disadvantages in the wording of existing treaties. Methods of judgement independent of the type of projectile. Possibilities of standardization. Tables. Index of Tables Previously Presented in this Book. Conversion Tables. Lengths. Velocity. Mass units. Force. Pressure. Energy and work. Temperature. Material Properties. Fluids and fluidal substances. Solid substances. Caliber Designations. Caliber designation metric units. Caliber designation US units. Ballistics Data of Ammunition. Ballistics data metric units. Ballistics data US units. Projectile Designations. Projectile shape. Projectile material. Projectile construction. Geometrical Data of Some Particular Projectiles. Military projectiles. Additional projectiles. Twists Lengths, Twist Angles and Number of Revolutions.Pistols and revolvers. Rifles. Firing Tables. Pistols and revolvers. Rifles. Signal and illumination ammunition. Shotgun Calibers and Shot Pellets. Calibers of shot barrels. Ballistics properties of shot pellets. Designation of buck shot sizes. Designation of normal shot sizes (Anglo-American system). Designation of normal shot sizes (metric system). Glossary. English-German-French. German-English-French. French-German-English. Literature. Bibliography. References. Illustration References. Index.

Semiclassical transition probabilities for the electron‐impact excitation of hydrogenic ions in dense plasmas

Abstract: Plasma‐screening effects are investigated on semiclassical transition probabilities for electron‐impact excitation of hydrogenic ions in dense plasmas. The electron–ion interaction potential is obtained by a nonspherical Debye–Huckel model of the screened Coulomb interaction for the interesting domain of the Debye length Λ/aZ≥10. Semiclassical straight‐line trajectory method is used to describe the behavior of the projectile electron. The screening effect is increased with increasing the projectile energy. The plasma‐screening effect on the optically allowed (dipole) transition (1s→2p) is found to be more effective than that on the optically forbidden transition (1s→2s). For 1s→2s transition, the maximum position of the transition probability is almost unchanged with increasing or decreasing the projectile energy and plasma‐screening effect. However, for 1s→2p transition, the maximum position of the transition probability has receded from the nucleus as the projectile energy increases.

Baryon rapidity loss and midrapidity stacking in high energy nucleus-nucleus collisions.

Abstract: Rapidity distributions of baryons from nucleus-nucleus, {ital p}-nucleus, and {ital p}-{ital p} interactions at 11.6, 14.6, and 200 GeV/{ital c} per nucleon incident momenta are reviewed. Average rapidity losses relative to the beam rapidity are derived in a consistent way and the systematics are described and discussed. The baryon multiplicities in the midrapidity region relative to simple geometrical sum rules are determined and the systematics of the opacity of the collisions are described. The main conclusions are that the average rapidity losses in central nucleus-nucleus collisions scale with the projectile rapidity and that the opacity of central collisions depends strongly on the size of the collision system and weakly on incident momentum.

Electro-mechanical roll control apparatus and method

Abstract: An apparatus and method for controlling roll of a projectile is disclosed. The projectile includes two sections decoupled about a roll axis. The front section includes a stator and the rear section includes a rotor and a static spin imparting member. The spin rate of the projectile is controlled by utilizing the rotor and stator in combination as a generator to brake the spin or as a motor to establish spin.

Projectile, in particular non lethal bullet

Abstract: The projectile, in particular a bullet, comprises a body (1) comprising a receiving cavity (6) containing a product (8) which is active on the organism of a live target, and means for releasing this product upon the impact of the projectile on the target. The body (1) of the projectile includes a propelling motor (5) and, along the length of the body, a portion (30) of smaller diameter followed by a shoulder (32) constituting a braking plane perpendicular to the direction of travel of the projectile. Application in bullets for disabling an opponent with no risk of fatal injury.

Cannon for disarming an explosive device

Abstract: A projectile substance is pneumatically propelled. The projectile substance is inserted onto a longitudinal bore of a barrel and a rupture disk is attached to a first end of the barrel. Next, the first end of the barrel is coupled to a first end of a pneumatic reservoir having a chamber therein. The rupture disk, as attached, acts to form a seal between the longitudinal bore and the chamber. Then, a gas is introduced into the chamber until a sufficient pressure is attained within the chamber to rupture the disk. When the disk ruptures, the gas in the chamber rushes into the longitudinal bore with sufficient force to propel the projectile substance out of the barrel. One or more pistons may be slidably disposed within the chamber to form more than one chamber portion. An average pressure for propelling the projectile substance may be increased by various methods of forcing the piston(s) toward the projectile substance as it is being driven out of the barrel. Additionally, if more than one piston, for example two pistons, are provided, the pistons may have different end surface areas to create a pressure multiplication effect. Accordingly, the pressure available for propelling the projectile substance can be greater than the source pressure. Also, rupture pressure in the chamber can be achieved by heating a liquid in the chamber.

Guided projectile system

Abstract: A system for guiding the flight of a projectile to a target. The system comprises a tracking and guidance system, the projectile, and a projectile reference and control system that is part of the projectile. The tracking and guidance system includes a target tracker, a projectile tracker for providing a projectile-tracking laser beam, and a target designator for designating the target using a target-tracking laser beam, and for providing range data indicative of the range to the target. A processor is coupled to the target designator, the target tracker, and the projectile tracker for processing target and projectile return signals and target range signals to generate an actuator command signal that is transmitted by the projectile tracker using the projectile-tracking laser beam and that is used to alter the flight of the projectile. The projectile reference and control system includes an optical reference including polarized and unpolarized retroflectors for reflecting the projectile-tracking laser beam back to the projectile tracker, and a detector that is responsive to the projectile-tracking laser beam provided by the projectile tracker, for detecting the actuator command signal transmitted by the projectile tracker. A command operated actuator is coupled to the detector for processing the actuator command signal and for generating a trajectory modification signal that is used to alter the flight of the projectile. A divert assembly coupled to the command operated actuator for generating thrust that diverts the trajectory of the projectile in response to the trajectory modification signal.

Design and evaluation of coils for a 50 mm diameter induction coilgun launcher

Abstract: Coilguns have the ability to provide magnetic pressure to projectiles which results in near constant acceleration. The authors have developed coils to produce an effective projectile base pressure of 100 MPa (1 kbar) as a step toward reaching base pressures of 200 MPa. The design uses a scalable technology applicable to the entire range of breech to muzzle coils of a multi-stage launcher. This paper presents the design of capacitor-driven coils for launching nominal 50 mm, 350 g projectiles. Design criteria, constraints, mechanical stress analysis, launcher performance, and test results are discussed. >

Athletic projectile and target training device

Abstract: A device for allowing an athlete to practice various methods of propelling a projectile in a controlled and accurate manner by allowing him/her to place the projectile on a specific location on a target. This device uses hook and loop fastening material on the projectile and the target to allow the athlete to know where the projectile strikes the target and allow him/her to practice various ways of getting the projectile onto the target. The reversible nature of the target allows the athlete to practice different sports using the same apparatus or to practice skills required in different situations encountered in the same sport.

Portable sports target frame

Abstract: A portable sports target frame is described for numerous sports games in which a projectile such as a ball or puck is used. The target frame includes an elongated cross member with uprights mounted at opposed ends. The uprights are mounted by an angular adjustment that enables selective pivotal adjustment of the uprights to positions simulating different sports targets. The cross member is held in the selected angular position by a parallelogram linkage including base standards and a parallel stabilizing link mounting the elongated cross member to a base for pivotal movement while maintaining the uprights in selected angular orientations. A latch is mounted between the linkage and base to permit selective angular positioning of the base standard relative to a platform. A ball or other projectile may be mounted to the platform by a tether which includes an elastic part secured to the projectile and an inelastic part extending to the projectile. The tether is long enough to allow the projectile to be thrown, kicked, or struck into a net suspended between the uprights. The elastic part is provided to return the projectile to the user.

The Scintillation detector equipment of the GSI projectile fragment separator

Abstract: A complete identification in mass and nuclear charge for relativistic projectile fragments up to uranium is possible at the fragment separator (FRS) at GSI by using the scintillation detector equipment described in this paper. It was successfully used in experiments with primary beams ranging from oxygen to uranium with energies from 300 to 1000 A MeV. A mass-resolving power of A/ΔA = 407 (FWHM) was obtained for 0.95 A GeV 238U fragments.

Dynamics of oblique detonations in ram accelerators

Abstract: Time-accurate numerical simulations are used to study the dynamic development of oblique detonations on accelerating projectiles in ram accelerators These simulations show that the oblique detonation can be stabilized on the projectile The high pressure generated behind the detonation can result in accelerations up to 106G and propel the projectile to velocities higher than 40 km/s The detonation structure on the projectile is sensitive to the projectile geometry A small change in the projectile shape is sufficient to alter the overall detonation structure and significantly affect the pressure distribution on the projectile In order to maximize the thrust, an appropriate projectile shape has to be chosen to generate the detonation structure just behind the widest part of the projectile body The projectile acceleration also has strong effects on the flow field and the detonation structure During the acceleration, the location of the oblique detonation moves upstream from one reflected shock to another However, one the detonation is stabilized behind the upstream shock, it remains at the new location until the transition to the next upstream shock occurs In the simulations, the Non-Inertial-Source (NIS) technique was used to accurately represent of the projectile acceleration Also, the Virtual-Cell-Embedding (VCE) method was employed to efficiently treat the complex projectile geometry on cartesian grids

Nonlinear screening and stopping powers at finite projectile velocities

Abstract: We have studied the nonlinear screening and stopping power of charged projectiles moving through a uniform electron gas with velocities up to the Fermi velocity of the gas. Our approach is based on density functional theory and is an extension of previous calculations which consider the screening of the projectile in the zero velocity limit. At the higher velocities considered here, the electrons of the metal occupy a shifted Fermi sphere which leads to an asymmetry of the screening charge density and scattering potential along the line of motion of the projectile. To obtain an approximate self-consistent solution of this dynamic screening problem, we use the spherically averaged density to define an averaged scattering potential (spherical potential approximation). As a specific application, we determine the axial screening charge density and stopping power of antiprotons in an electron gas characteristic of aluminium. Screening nonlinearities are found to be important for the full range of velocities considered. In addition, we find that the stopping power exhibits a linear dependence on velocity up to velocities approaching the stopping power maximum.

Current and heat transport in the solid-armature railgun

Abstract: A numerical model is developed for solving the equations which predict current and heat transport in a series-augmented, solid-armature railgun. The model is two dimensional and fully time dependent. Specific calculations are then carried out to analyze the armature recently designed and developed in the Cannon Caliber Electromagnetic Launcher Program. The most extensive computations are for a situation in which the projectile is started at rest and accelerated to nearly 2 km/s in a time of 2 ms. Results of the calculations can be used to infer, for example, where melting in the armature is most likely to occur and where the electromagnetic stresses are largest. For comparison, calculations are also presented for a situation in which the projectile is held fixed. These calculations are intended to demonstrate the importance of velocity effects in the design of solid-armature railguns. >

Projectile image acceleration, neutralization and electron emission during grazing interactions of multicharged ions with Au(110)

Abstract: Recent Oak Ridge work is summarized on projectile energy gain by image charge acceleration, scattered ion charge distributions, and K-Auger electron emission during low energy grazing interactions of highly charged Pb, I, O and Ar ions with a Au(110) surface.

Computational study of large-disturbance oscillations in unsteady supersonic combustion around projectiles

Abstract: Unsteady combustion around a spherical projectile in supersonic flows is numerically studied using the simplified two-step chemical reaction model consisting of the induction and the exothermic reactions. A series of simulations indicates that the intensity of the concentration of the heat release is a key parameter to determine the regime of the unsteady flowfield. Flow features of the unsteady combustion with low-frequency and high-amplitude oscillation, which is called the large-disturbance regime, are reproduced when the concentration of the heat release of the chemical reaction is high. Mechanism of the large-disturbance regime is clarified based on the histories of the density and pressure profiles on the stagnation streamline and the flowfield in front of the projectile body. The period and amplitude of the oscillation corresponding to the shock pressure behind the how shock agree with experimental observations, and the reproduction of the large-disturbance regime in the present simulation is confirmed.

In-bore projectile dynamics in the linear induction launcher (LIL). 1. Oscillations

Abstract: The projectile in a linear induction launcher is subject to centering (levitation) forces, as well as propelling ones. Due to their uneven distribution, these forces give rise to rotation, as well as translation of the projectile axis. This paper assesses these motions. >

New higher-order Godunov code for modelling performance of two-stage light gas guns

Abstract: A new quasi-one-dimensional Godunov code for modeling two-stage light gas guns is described The code is third-order accurate in space and second-order accurate in time A very accurate Riemann solver is used Friction and heat transfer to the tube wall for gases and dense media are modeled and a simple nonequilibrium turbulence model is used for gas flows The code also models gunpowder burn in the first-stage breech Realistic equations of state (EOS) are used for all media The code was validated against exact solutions of Riemann's shock-tube problem, impact of dense media slabs at velocities up to 20 km/sec, flow through a supersonic convergent-divergent nozzle and burning of gunpowder in a closed bomb Excellent validation results were obtained The code was then used to predict the performance of two light gas guns (15 in and 028 in) in service at the Ames Research Center The code predictions were compared with measured pressure histories in the powder chamber and pump tube and with measured piston and projectile velocities Very good agreement between computational fluid dynamics (CFD) predictions and measurements was obtained Actual powder-burn rates in the gun were found to be considerably higher (60-90 percent) than predicted by the manufacturer and the behavior of the piston upon yielding appears to differ greatly from that suggested by low-strain rate tests

Photon angular distributions from radiative electron capture in relativistic atomic collisions

Abstract: A detailed discussion is given of the general behavior of differential cross sections for radiative electron capture in relativistic and nonrelativistic heavy-ion--atom collisions. From angular-momentum conservation and a simple approximate treatment, the basic qualitative features can be derived in an analytic form. Subsequently, the results of rigorous relativistic calculations are presented graphically for a sequence of projectile charges and projectile energies. It is shown that in radiative electron capture, the influence of the electron spin manifests itself in a particularly clear-cut way.

Experiments with the Green Farm electric gun facility

Abstract: The design and construction of a major electric gun facility at Green Farm in San Diego is described. The facility is driven by an 11 kV 32 MJ capacitor bank, arranged in 4 MJ modules that can be independently triggered to provide a choice of pulse shapes. The bank has powered a variety of EM and ET guns, including an 8-meter Single Shot Rail gun and a modified 5-inch Naval gun. World record high energy and high velocity shots have been achieved. The highest rail gun muzzle energy was 8.6 MJ and the highest muzzle velocity was 4.3 km/s with a plasma driven projectile of 0.64 kg, corresponding to a muzzle energy of 6 MJ. Intact projectile launch and flight was confirmed by high speed (8000 frames/sec.) photography and flash X-rays. >

Technique for the continuous measurement of projectile velocities in plate impact experiments

Abstract: This paper describes a simple yet accurate technique for the continuous measurement of projectile velocities in plate impact experiments (the impact velocity is a critical parameter in the interpretation of such experiments). The technique, known as the laser line velocity sensor (LLVS), uses a laser line generator to generate a laser sheet of uniform intensity that is incident on a photodiode at the focus of a collecting lens. The amount of light reaching the photodiode diminishes as the projectile intersects the laser sheet, and so a simple calibration procedure in conjunction with a high‐bandwidth optoelectronic system provides a measure of the projectile velocity. Since the measurement is continuous, both the projectile velocity and acceleration can be obtained. The LLVS is very stable, does not need reconstruction after impact, does not need frequent recalibration, and is insensitive to rigid body motions. An example of the application of the technique is provided.

Experimental results and performance analysis of a 500 m/sec linear induction launcher (LIL)

Abstract: A computer model, previously validated, was used to study the performance of an experimental three-phase launcher energized by a capacitor bank and designed to impart to a 137 gram projectile a muzzle velocity of 500 m/s: (1) the build-up of the traveling wave was examined; (2) the connection of the drive coils was changed; (3) the resistances of the drive circuits were calculated and measured; and (4) the effect of the conductivity of the cylindrical tube (sleeve) constituting the projectile was assessed. Experimentally, a doubling of the muzzle velocity was achieved, from an earlier-obtained 250 m/s, to its present 476 m/s. This was done by strengthening the thin-walled aluminum sleeve by heat treatment (aging) to prevent it from being crushed when the input energy was raised to its design value. >