Showing papers on "Projectile published in 2015"

Accurate atomistic first-principles calculations of electronic stopping

Abstract: We show that atomistic first-principles calculations based on real-time propagation within time-dependent density functional theory are capable of accurately describing electronic stopping of light projectile atoms in metal hosts over a wide range of projectile velocities. In particular, we employ a plane-wave pseudopotential scheme to solve time-dependent Kohn-Sham equations for representative systems of H and He projectiles in crystalline aluminum. This approach to simulate nonadiabatic electron-ion interaction provides an accurate framework that allows for quantitative comparison with experiment without introducing ad hoc parameters such as effective charges, or assumptions about the dielectric function. Our work clearly shows that this atomistic first-principles description of electronic stopping is able to disentangle contributions due to tightly bound semicore electrons and geometric aspects of the stopping geometry (channeling versus off-channeling) in a wide range of projectile velocities.

Projectile with enhanced ballistics

Abstract: The present invention provides a projectile device and a method of manufacture of a projectile device and in particular, to a pistol bullet and a rifle bullet and method of manufacture of same. In one embodiment, the projectile apparatus has a cylindrical body portion having a diameter, a front nose section tapering from a most proximal point of the projectile to the cylindrical body portion, and a rear tail section connected to the body portion and extending to the most distal point of the projectile, in which the front nose portion comprises a plurality of twisting depressions forming troughs.

Large caliber frangible projectile

Abstract: A large caliber, frangible, training projectile imitates, for training purposes, the corresponding tactical projectile. To enable fragmentation of the training projectile at impact, some embodiments of the frangible projectile are partially or entirely made of a material with a lower yield strength than the material used in the counterpart tactical projectile. Some embodiments of the frangible projectile may include portions that are sectioned, welded, or provided with stress risers. Some embodiments of the frangible projectile may include high density particles suspended in a weaker medium. The fragmentation methods may be applied to the overall mass of the projectile, or to a portion of the projectile.

Method of making a projectile by metal injection molding

Abstract: The present invention provides a method of making a metal ammunition projectile by metal injection molding comprising the steps of: providing a projectile mold to form a nose extending essentially symmetrically to a shoulder; and an essentially cylindrical bearing surface extending from the shoulder to a base; providing a metal injection molding feedstock comprising a powdered metal and a first binding agent and a second binding agent; injection molding the metal injection molding feedstock into the projectile mold to form a first projectile having a first size; debinding the first projectile to remove the first binding agent; and sintering the first projectile to remove the second binding agent and form a projectile having a second size.

Ammunition having a projectile made by metal injection molding

Abstract: The present invention provides ammunition having a metal injection molded projectile and a metal cartridge case comprising a metal ammunition cartridge comprising a unitary body that enclose a propellant chamber, a primer recess in a bottom portion of the unitary body, a primer flash hole that connects the primer recess and the propellant chamber, and a projectile aperture in communication with the propellant chamber; a primer inserted into the primer flash hole aperture; a propellant at least partially filling the propellant chamber; and a metal injection molded projectile frictionally fitted in the projectile aperture, wherein the metal injection molded projectile comprises a nose extending essentially symmetrically to a shoulder, and an essentially cylindrical bearing surface extending from the shoulder to a base.

Study on the Similarity Laws for Local Damage Effects in a Concrete Target under the Impact of Projectiles

Abstract: The local destruction and deformation characteristics of a concrete target impacted by a rigid projectile were analyzed, and the similarity laws for local damage effects in the concrete target were studied utilizing the rigid-plastic, internal friction, and modified hydrodynamic models. For a thin target, the impact factor is the only factor controlling the low-velocity impact process. For a thick target impacted by a projectile at intermediate velocity, internal friction is the main factor contributing to the energy dissipation. The impact factor, the toughness factor, and the dynamic factor together determine the penetration process. However, for a thick target impacted at high velocity, the impact factor and hardness factor together determine the penetration process. The penetration depth shows a 2/3 power relationship with impact velocity. For thick targets, similarity laws change along with impact velocity. The radii ratio between the projectile and penetration tunnel is proportional to the projectile’s diameter for intermediate velocity impact and only shows a relationship with the impact velocity for high velocity penetration.

Global optical model potential for alpha projectile

Abstract: A new set of global phenomenological optical model potential (OMP) parameters for alpha projectile is obtained by simultaneously fitting the experimental data of reaction cross-sections and elastic scattering angular distributions in the mass range of target nuclei 20 ≤A ≤ 209 at incident energies below 386MeV. The total reaction cross-sections and elastic scattering angular distributions are calculated and compared with experimental data for different targets. A satisfactory agreement is presented between them.

Polymer ammunition having a projectile made by metal injection molding

Abstract: The present invention provides an ammunition having a metal injection molded projectile and a polymer cartridge case comprising a polymer ammunition cartridge comprising a bottom portion and a top portion that enclose a propellant chamber, wherein the bottom portion comprises a primer recess in communication with a primer flash hole that extends into a propellant chamber and the top portion comprises a projectile aperture; a primer inserted into the primer flash hole aperture; a propellant at least partially filling the propellant chamber; and a metal injection molded projectile frictionally fitted in the projectile aperture, wherein the metal injection molded projectile comprises a nose extending essentially symmetrically to a shoulder, and an essentially cylindrical bearing surface extending from the shoulder to a base

Dynamics of hypervelocity jetting during oblique impacts of spherical projectiles investigated via ultrafast imaging

Abstract: A series of hypervelocity impact experiments was conducted in a new laboratory at Planetary Exploration Research Center of Chiba Institute of Technology (Japan). We present the results of high-speed imaging observations of impact jetting during blunt-body penetration under oblique impacts. The observations were sampled at a frame rate of 100 ns frame−1, which is much shorter than the characteristic time of projectile penetration under our experimental conditions. The maximum jet velocity was obtained as a function of both impact velocity and the contrast of shock impedance between a projectile and target, enabling us to test theoretical models of impact jetting during oblique impacts of spherical projectiles. We find that the jet velocities measured in this study are much slower than the prediction by the standard theory based on the previous experimental/theoretical results of collisions between two metal plates. A decaying shock pressure during blunt-body penetration is a possible origin of the discrepancy. We also present a new formulation of the jet velocity with the equations of state for realistic materials. The particle velocities of ejected materials from a free surface are calculated using the Riemann invariant along the isentropes and the Tillotson equations of state in this study. Based on the extremely high velocity of the jet, we point out that impact jetting might contribute to chemistry near the ground surface of planets/satellites with a thick atmosphere, such as Titan.

Metal injection molded projectile

Abstract: The present invention provides a molded metal ammunition projectile comprising: a metal composition injected into a molded to form a projectile comprising a nose extending essentially symmetrically to a shoulder; an essentially cylindrical bearing surface extending from the shoulder to a base.

Centralized system proving notification of incoming projectiles

Abstract: Described embodiments include a real-time system, method, and apparatus. A system includes an incoming object sensor configured to acquire data indicative of a trajectory of an incoming projectile. The system includes a human tracking circuit configured to acquire data indicative of a location of a human present in a monitored geographic area. The system includes a processing circuit configured to (i) receive the data indicative of the trajectory of the incoming projectile; (ii) predict a spatial relationship of the trajectory of the incoming projectile relative to the location of the human; and (iii) determine a suggested movement by the human to evade the incoming projectile. The system includes a transmitter circuit configured to transmit the suggested movement to evade the incoming projectile.

A Scenario for a Future European Shipboard Railgun

Abstract: Railguns can convert large quantities of electrical energy into kinetic energy of the projectile. This was demonstrated by the 33-MJ muzzle energy shot performed in 2010 in the framework of the Office of Naval Research electromagnetic railgun program. Since then, railguns have been a prime candidate for the future long-range artillery systems. In this scenario, a heavy projectile (several kilograms) is accelerated to approximately 2.5-km/s muzzle velocity. While the primary interest for such a hypersonic projectile is the bombardment of targets hundreds of kilometers away, they can also be used to counter airplane attacks or in other direct fire scenarios. In these cases, the large initial velocity significantly reduces the time to impact the target. In this paper, we investigate a scenario, where a future shipboard railgun installation delivers the same kinetic energy to a target as the explosive round of a contemporary European ship artillery system. At the same time, the railgun outperforms the current artillery systems in range. For this scenario, a first draft for the parameters of a railgun system was derived. For the flight path of the projectile, trajectories for different launch angles were simulated and the aerothermodynamic heating was estimated using engineering tools developed within the German Aerospace Center (DLR). This enables the assessment of the feasibility of the different strike scenarios, as well as the identification of the limits of the technology. It is envisioned that this baseline design can be used as a helpful starting point for discussion of a possible electrical weaponization of the future European warships.