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Analysis of longitudinal and lateral of ballistic rocket dynamics is presented in this paper. The dynamic analysis is carried out by linearizing the equation of motion of the rocket. The effect of an inaccurate geometric parameters of the location of the center of gravity (CG) in the longitudinal direction, location of the center of gravity in the normal direction, moment of inertia Iyy, and nose shape from its on-design parameter on dynamics characteristics, are presented. The effects of variation of these parameters will be analyzed based on its poles location, bode plot, and step response due to input from the control surface. [ABSTRACT FROM AUTHOR]

Currently, pyrotechnic devices are widely used in rocketry. They are described by the same system of equations as a muzzle-loading smooth-bore gun. Meanwhile, as shown in the previous works of the authors, modern ideas about the internal ballistics of these weapons, apparently, are not correct. The article continues the cycle of works on the creation of a mathematical model of these systems. The article assesses the degree of influence on the muzzle velocity of the heterogeneity of the powder grains. It is shown that, regardless of the distribution law (normal or not), with a sufficient degree of accuracy (about 1.5%), the combustion of such grains can be approximated by the combustion of identical grains of any diameter from the selected range. The only prerequisite is the condition of equality of the initial combustion area. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model and code-implemented engineering calculation technique that allow to study workflow inside a ramjet's combustion chamber under dynamic variation of external and internal parameters: flight speed, angle of attack, and fuel mass flow rate. To assess adequacy of the mathematical model and the technique, a comparison is performed between results of internal ballistics calculations of a spaceplane's ramjet obtained by aforementioned mathematical model and by numerical simulation in a computational fluid dynamics software package. This is tested for cruise flight conditions and for dynamic variation of flight parameters and fuel mass flow rate in a wide range. It shows that for a model subsonic flow combustion chamber a satisfactory correlation between these solutions is realized. Transient processes are stable and monotonous for all cases studied, registered oscillations of total pressure and temperature in relation to their stabilized values and weak overshooting have no effect on the engine's output characteristics. [ABSTRACT FROM AUTHOR]

The arcticle gives a spatial gas-dynamic formulation of the backpressure problem, which describes the change in pressure in front of an accelerating projectile when it moves along the bore. This takes into account the geometry of the front of the projectile and its influence on the formation of the shock wave. An unsteady spatial flow of the displaced medium ahead of the projectile body without and taking into account the forces of viscosity is considered. The paper considers the solution to the problem of throwing a body using the energy of gunpowder combustion. The internal ballistics problem, which determines the dynamics of the projectile movement, is solved in terms of averaged parameters. A two-step Runge-Kutta scheme with a second order of accuracy is used to numerically integrate a system of ordinary differential equations in time. The control volume method is used for the numerical solution of the system of gas-dynamic equations. The gas parameters at the boundaries of the control volumes are determined using a self-similar solution to the problem of the decay of an arbitrary discontinuity. A comparison is presented of taking into account the backpressure as the pressure behind the detached shock wave, obtained from the analytical solution of the problem of the supersonic motion of a flat piston in a pipe at a constant velocity, and the pressure acting on the projectile, determined from the solution of nonstationary one-dimensional and spatial (axisymmetric) equations of gas dynamics. It was found that taking into account the viscosity practically does not affect the results of calculating the backpressure, while taking into account the shape of the front part of the projectile leads to a significant difference in the pressure fields behind the front of the shock wave compared to the solution in the framework of the one-dimensional formulation of the problem, where the shape of the front part of the projectile cannot be taken into account. It is concluded that this can significantly affect the results of modeling the ballistics of a shot at high throwing speeds. [ABSTRACT FROM AUTHOR]

Penetration depth is the most important parameter in terminal ballistics. Here only the case of projectiles penetrating granular medium is considered. Laboratory and field tests have shown that projectile characteristics such as mass, size, and nose shape, and target characteristics such as strength and density determine the depth of penetration. Analyses of full flight data recorded by onboard data acquisition system (G-Rec) are presented. These tests have revealed very high decelerations at impact with extensive particle fracture along the path of the projectile. Particle size distribution analysis of the sample collected from the projectile tip shows two to three orders of magnitude reduction in size. For similar impact velocities and target densities, Poncelet's coefficient does not vary with tip shape. [ABSTRACT FROM AUTHOR]

In this paper, by calculations, the possibility to increase the speed of a bullet firing from the VPO-208 carbine is shown by increasing the total mass of the propellant charge without exceeding the maximum pressure of the powder gases in case of using the charge separation into two parts. Mathematical modeling of the “relay” scheme applied to the firing is based on the approach of the heterogeneous media mechanics used to study the internal ballistics of the receiver systems. Calculations have shown the possibility to increase the speed of a bullet with the use of a "relay" scheme by approximately 12% compared to the speed of a bullet obtained using a classical firing scheme. [ABSTRACT FROM AUTHOR]

Numerical simulations were carried out to study the ballistic resistance of double-layered metal plates subjected to normal impact by the ogive-nose projectiles. 12 mm thick Weldox 460E steel targets consisted of two 6 mm thick plates in contact were impacted by 20 mm diameter ogive-nose projectiles. The caliber radius head (CRH) of ogive-nose projectile was varied (0 - 5.0) and found to have obvious effect on the ballistic limit of 12 mm thick double-layered Weldox 460E steel plates. Double-layered plates were found to be less effective than the equivalent monolithic targets for CRH ≥ 0.5, and more effective with CRH = 0. LS-DYNA finite element code in conjunction with Johnson–Cook elasto-viscoplastic material model was employed to carry out the numerical simulations [ABSTRACT FROM AUTHOR]

The U.S. Army Research Laboratory, in conjunction with Lawrence Livermore National Laboratory, is developing a Multi-Energy Flash Computed Tomography (MEFCT) diagnostic that will be used to capture tomographic image(s) of dynamic impact and detonation events. To accomplish dynamic tomography, the diagnostic uses numerous source--detector pairs to accumulate up to fifteen two-dimensional images, which are subsequently used to compute up to three three-dimensional tomographic reconstructions. The diagnostic is designed to provide either: a single-frame, threedimensional tomographic reconstruction that delineates material specificity throughout the field, or a three-frame tomographic reconstruction movie spaced in time, while lacking the information pertaining to the material specificity. This work assesses aspects of the diagnostic development including structural design, dynamic capability, instrument resolution and computational reconstruction. Examples of real-time measurements are provided from static phantom fiducials, as well as a dynamic experiment depicting a non-symmetric ballistic penetration to demonstrate the usefulness of the capability. [ABSTRACT FROM AUTHOR]

Ballistics trajectory and impact conditions calculations were conducted in order to investigate the origin of the projection criteria for Insensitive Munitions (IM) and Hazard Classification (HC). The results show that the existing IM and HC projection criteria distance-mass relations are based on launch energy rather than impact conditions. The analysis shows that at the maximum throw distances, the impact energy is generally much smaller than the launch energy. Using maximum distance projections, new distance-mass relations were developed that match the criteria based on impact energy at 15m and beyond rather than launch energy. Injury analysis was conducted using penetration injury and blunt injury models. Blunt injury dominates the assessment of injury or lethality. State of the art blunt injury models predict only minor injury for a 20J impact. For a 79 J blunt impact, major injury is likely to occur. [ABSTRACT FROM AUTHOR]

Analyzing the response of modern mobile platforms to ballistic impact is a challenge due to target mobility and inherent structural loads. The present work involves an experimental and numerical analysis of ballistic impact against simulated moving targets that are pre-stressed. Realization of the target movement was achieved by launching an inclined elongated projectile at an oblique target, with equal inclination and obliquity resulting in an experimental set-up corresponding to normal impact of the target plate by the projectile with a transverse velocity component. The present experimental analysis considers impact by a 0.5" calibre projectile against the aluminium target, with the objective to analyze the target damage. The modelling results reasonably agree with the experiments. [ABSTRACT FROM AUTHOR]

Hybrid composites have been fabricated by hand lay-up technique with epoxy resin and diethylene tri amine as a hardener for high impact energy absorption with sandwich stacking of different reinforcements of dyneema and glass fabric. High impact grade composites are nowadays gaining a lot of importance in the field of high mechanical load bearing applications, ballistics and bulletproofing. The present work emphases on the fabrication and mechanical properties of the hybrid composites of cut resistant dyneema fabric along with glass fabric reinforced in the thermosetting resin. i.e. epoxy. The prime importance while fabricating such materials have been given to the processing along with selection of the raw materials. High impact resistive materials with low density and henceforth low weight have been manufactured and characterized by IZOD impact tester, UTM, Archimedes density meter and SEM. Throughout the work, satisfactory results have been obtained. Impact resistance was observed to be boosted three times as that of the reference sample of glass fabric and epoxy. The density of the hybrid composite is observed to be 25% as that of the reference sample. [ABSTRACT FROM AUTHOR]

Frangible bullet is designed to disintegrate upon impact against a hard target. Understanding the impact response and performance of frangible bullet is therefore of highly interest. In this paper, simulation of impact ballistic of Cu-IOwt%Sn frangible bullet using smoothed particle hydrodynamics (SPH) method is presented. The frangible bullet is impacted against a hard, cylindrical stainless steel target. Effect of variability of the frangible bullet material properties due to the variation of sintering temperature in its manufacturing process to the bullet frangibility factor (FF) is investigated numerically. In addition, the bullet kinetic energy during impact as well as its ricochet and fragmentation are also examined and simulated. Failure criterion based upon maximum strain is employed in the simulation. It is shown that the SPH simulation can produce good estimation for kinetic energy of bullet after impact, thus giving the FF prediction with respect to the variation of frangible bullet material properties. In comparison to explicit finite element (FE) simulation, in which only material/element deletion is shown, convenience in showing frangible bullet fragmentation is shown using the SPH simulation. As a result, the effect of sintering temperature to the way of the frangible bullet fragmented can be also observed clearly. [ABSTRACT FROM AUTHOR]

The problems of the defense industry occupy the most important place in the constantly developing modern world. The daily development of defense technology does not stop, nor do studies on internal ballistics. The scientists of the whole world are faced with the task of managing the main characteristics of a ballistic experiment. The main characteristics of the ballistic experiment are the maximum pressure in the combustion chamber Pmax and the projected velocity at the time of barrel leaving UM. During the work the combustion law of the new high-energy fuel was determined in a ballistic experiment for different initial temperatures. This combustion law was used for a parametric study of depending Pmax and UM from a powder charge mass and a traveling charge was carried out. The optimal conditions for loading were obtained for improving the initial velocity at pressures up to 600 MPa for different initial temperatures. In this paper, one of the most promising schemes of throwing is considered, as well as a method for increasing the muzzle velocity of a projected element to 3317 m/s. [ABSTRACT FROM AUTHOR]

In the article two series of ballistic experiments conducted according to the scheme of electrothermal chemical control of ballistic parameters of the shot at the Research Institute of Applied Mathematics and Mechanics of Tomsk State University (RIAMM TSU, Russia) are considered. The experimental part of the work is described. The analysis of the electro physical data of ballistic experiments is carried out. A methodical approach that allows to take into account the entry of an electric discharge plasma in a gunpowder in the mathematical model of internal ballistic processes in barrel systems is proposed and tested. Under the conditions of these experiments, the effects of various characteristics of the plasmatron on the nature of the energy entry are estimated. [ABSTRACT FROM AUTHOR]

The article is devoted to the development of methods for solving the problem of external ballistics using a more complete system of motion equation taken into account the rotation and oscillation about the mass center and using aerodynamic coefficients of forces and moments which are calculated on the basis of modeling the hydrodynamics of flow around the projectile. Developed methods allows to study the basic ways of increasing the shooting range or artillery. [ABSTRACT FROM AUTHOR]

The contribution describes the concept and numerical simulation of a ballistic protective layer which is able to actively resist projectiles or smaller colliding fragments flying at high speed. The principle of the layer was designed on the basis of the action/reaction system of reactive armour which is used for the protection of armoured vehicles. As the designed ballistic layer consists of steel plates simultaneously combined with explosive material - primary explosive and secondary explosive - the technique of coupling the Finite Element Method with Smoothed Particle Hydrodynamics was used for the simulations. Certain standard situations which the ballistic layer should resist were simulated. The contribution describes the principles for the successful execution of numerical simulations, their results, and an evaluation of the functionality of the ballistic layer. [ABSTRACT FROM AUTHOR]

We are developing a new diagnostic useful for the non-invasive detection of projectile passage in the launch tube of a gas gun. The sensing element consists of one or more turns of single-mode optical fiber that is epoxy-bonded around the external circumference of the launch tube. The hoop strain induced in the launch tube by the passage of the projectile causes a momentary expansion of the fiber loop. This transient change in path length is detected with high sensitivity using a fiber optic-based interferometer developed by the NSTec Special Technologies Laboratory. We have fielded this new diagnostic, along with fiber optic Bragg grating (FBG) strain gauges we previously used for this purpose, on a variety of gas guns used for shock compression studies at Los Alamos and Sandia National Laboratories.We anticipate that, when coupled with a broad-range analog demodulator circuit, the fiber optic interferometer will have improved dynamic range over that of the FBG strain gauge approach. Moreover, in contrast to the FBG strain gauge which is somewhat temperature sensitive, the interferometric approach requires no alignment immediately prior to the experiment and is therefore easier to implement. Both approaches provide early, pre-event signals useful for triggering high-latency diagnostics. [ABSTRACT FROM AUTHOR]

The investigation on free-surface impact of projectiles has last for more than one hundred years due to its noticeable significance on improving defensive weapon technology. Laboratory-scaled water entry experiments for trajectory stability had been performed with four kinds of projectiles at a speed range of 20~200 m/s. The nose shapes of the cylindrical projectiles were designed into flat, ogive, hemi-sphere and cone to make comparisons on the trajectory deviation when they were launched into water at a certain angle of 0~20°. Two high-speed cameras positioned orthogonal to each other and normal to the water tank were employed to capture the entire process of projectiles' penetration. From the experimental results, the consecutive images in two planes were presented to display the general process of the trajectory deviation. Compared with the effect of impact velocities and nose shape on trajectory deviation, it merited conclude that flat projectiles had a better trajectory stability, while ogival projectiles experienced the largest attitude change. The characteristics of pressure waves were also investigated. [ABSTRACT FROM AUTHOR]

The investigation on ballistic stability of high-speed projectile in granular materials is important to study the EPW (earth-penetrating weapon). Laboratory-scaled sand entry experiments for the trajectory in the sand have been performed at a range of velocities from 30 m/s to 150 m/s. In addition, pressure sensor was embedded in the sand to record the sand stress which reflects the penetration performance of projectile during the impact. The slender projectiles were designed into flat nose shape with three kinds of L/D (length-diameter ratio) to make comparisons on the trajectory when those projectiles were launched at normal and oblique impact angles (0~25deg) along a view window. A high-speed camera beside window was employed to capture the entire process of projectiles' penetration. Basing on the comparison of different tests, theoretical analysis is carried out on the relationship between ballistic stability and associated conditions. By utilizing DIC technique, the vector field of sand velocity was acquired, and the spreading direction of the impacting energy was observed. It can be concluded that the sand stress is the function of penetrating velocity, L/D and the shot angle. It increases with the growing of penetrating velocity and L/D, decreases with the shot angle. To a certain extent, the biggest initial velocity leads to the highest stress. [ABSTRACT FROM AUTHOR]

The research is focused on the simulation and experimental investigation of high-strain rate loading to study the mechanisms of plastic flow localization in metals (AlMg6) using a ballistic installation. Unique results of experiments are given in the paper. Numerical simulation using wide-range constitutive equations is done. The paper also shows the results of structural studies. [ABSTRACT FROM AUTHOR]

This paper presents the terminal ballistic of 3 mm thickness aluminium plate impacted by fragment simulating projectile (FSP). Up to days, not many researchers are keen into terminal ballistic. They are more focus towards ballistic limit. Therefore, there is a need to highlight terminal ballistic as such in this study. The experiment was conducted at the Science and Technology Research Institute for Defence (STRIDE) Batu Arang, Selangor. For recording purpose, digital high speed camera with the capability of 250,000 frames per second (max) and the highest resolution 1024x1024 was used. For the data acquisition and processing, Photron Fastcam Viewer (PFV) software was used. For numerical simulation purpose, commercial software code Hyperworks was employed. Results showed that there were four main failure stages, which were first contact between FSP and the plate, partial perforation, full perforation with FSP and plug still intact and lastly separation of FSP and plug. Good agreement was observed between experiment and numerical simulation. [ABSTRACT FROM AUTHOR]

The work presents opportunities of hydroballistic complex for studying the characteristics of movement supercavitation model (SCM) on the length of waterway to 10 m. Gunfire of SCM implemented by this complex allows to study movement and collision of the different masses of SCM with underwater obstacles at subsonic, transonic and supersonic velocities in water. During the movement of SCM different masses the behavior supercavity was investigated. [ABSTRACT FROM AUTHOR]

The problem of launchers used in civil applications is a topical issue. The role of a launcher is to launch objects with a certain speed towards certain goals like for example dangerous fire outbreaks (drilling areas, fires in buildings). This paper is aiming to present the theoretical aspects and results regarding the launching objects, in this case spheres that contains firefighting substance, during the launching stage, the ballistic stage and the impact stage with a solid surface. [ABSTRACT FROM AUTHOR]

The paper presents a calculation-experimental study on high-speed interaction of the metal projectile with a combined barrier made of porous corundum-based ceramics filled with chemically active composition (sulfur, nitrate of potash) in the wide range of speeds. A mathematical behavior model of porous corundum-based ceramics with chemically active filler is developed within the scope of mechanics of continuous media taking into account the energy embedding from a possible chemical reaction between a projectile metal and filler at high-speed impact. Essential embedding of inlet heat is not observed in the considered range of impact speeds (2.5 ... 8 km/s). [ABSTRACT FROM AUTHOR]

The process of high-speed impact of projectiles against targets of finite thickness is experimentally investigated. Medium-hard steel plates are used as targets. The objective of this research is to carry out a comparative analysis of dynamic effects of interaction of various types of projectiles with targets, such as characteristics of destruction of the target, the state of the projectile behind the target, and particularities of the after-penetration stream of fragments after the target has been pierced. The projectiles are made of composites on the basis of tungsten carbide obtained by caking and the SHS-technology. To compare effectiveness of composite projectiles steel projectiles are used. Their effectiveness was estimated in terms of the ballistic limit. High density projectiles obtained by means of the SHS-technology are shown to produce results comparable in terms of the ballistic limit with high-strength projectiles that contain tungsten received by caking. [ABSTRACT FROM AUTHOR]

Graphene is a new material of a single or multiple layer carbon structure with impressive properties. A brief introduction is initially presented. Graphene does not have a bandwidth and is a semimetal with charge carriers of zero mass. A bandgap can be formed by confining the graphene width in nanoribbon or nanoconstricition structures. For example, the induced bandgap by a 20 nm wide nanoribbon is about 50 meV. The charge carrier mass then increases, but is still very small. This material can especially be employed for various Terahertz applications. Here several examples are to be described, namely a) a THz transistor, b) the opportunities of ballistic electron resonances for THz signal generation, c) the simultaneous optical transmission and electrical conduction up to THz frequencies and d) Cascaded THz emitters. The optical advantages of multilayer graphene can be compared to ITO (Indium Tin Oxide). [ABSTRACT FROM AUTHOR]

We explore using GERBS, a blending-type spline construction, to represent deform able thin-plates and model terminal ballistics. Strategies to construct geometry for different scenarios of terminal ballistics are proposed. [ABSTRACT FROM AUTHOR]

Fast calculation of disturbing gravity is a key technology in ballistics while spherical cap harmonic(SCH) theory can be used to solve this problem. By using adjusted spherical cap harmonic(ASCH) methods, the spherical cap coordinates are projected into a global coordinates, then the non-integer associated Legendre functions(ALF) of SCH are replaced by integer ALF of spherical harmonics(SH). This new method is called virtual spherical harmonics(VSH) and some numerical experiment were done to test the effect of VSH. The results of earth’s gravity model were set as the theoretical observation, and the model of regional gravity field was constructed by the new method. Simulation results show that the approximated errors are less than 5mGal in the low altitude range of the central region. In addition, numerical experiments were conducted to compare the calculation speed of SH model, SCH model and VSH model, and the results show that the calculation speed of the VSH model is raised one order magnitude in a small scope. [ABSTRACT FROM AUTHOR]