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Showing papers on "Projectile published in 2014"


Journal ArticleDOI
TL;DR: In this paper, the authors describe mix design of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) and its response to deformable and non-deformable projectile impact.

188 citations


Journal ArticleDOI
TL;DR: In this article, the Lattice Discrete Particle Model for fiber reinforced concrete (LDPM-F) is calibrated and validated with reference to a new high-strength, ultra-high performance concrete (UHPC) named CORTUF and applied to the simulation of projectile penetration.

115 citations


Journal ArticleDOI
TL;DR: In this article, the impact response of sandwich specimens with FML skins and polyurethane foam was investigated by experimental and numerical approaches using LS-DYNA to model impact of cylindrical projectile with clamped boundary condition.

58 citations


Journal ArticleDOI
TL;DR: In this paper, an experimental investigation on the perforation behavior of 5754-H111 and 6082-T6 aluminium alloys has been conducted on conical, hemispherical and blunt projectiles.
Abstract: This paper presents an experimental investigation on the perforation behaviour of 5754-H111 and 6082-T6 aluminium alloys. The mechanical response of these materials has been characterized in compression with strain rates in the range of $10^{-3}~s^{-1} < \dot {\varepsilon } < 5 \cdot 10^{3}~s^{-1}$ . Moreover, penetration tests have been conducted on 5754-H111 and 6082-T6 plates of $4~mm$ thickness using conical, hemispherical and blunt projectiles. The perforation experiments covered impact velocities in the range of $50~m/s < V_{0} < 200~m/s$ . The initial and residual velocities of the projectile were measured and the ballistic limit velocity obtained for the two aluminium alloys for the different nose shapes. Failure mode and post-mortem deflection of the plates have been examined and the perforation mechanisms associated to each projectile/target configuration investigated. It has been shown that the energy absorption capacity of the impacted plates is the result of the collective role played by target material behaviour, projectile nose shape and impact velocity in the penetration mechanisms.

57 citations


Patent
27 Feb 2014
TL;DR: In this article, the authors defined a composite of a cured, toughened polymer resin and a particulate filler distributed through the resin, the filler having a density greater than a density of the resin.
Abstract: A projectile includes: (a) a cured, toughened polymer resin; and (b) a particulate filler distributed through the resin, the filler having a density greater than a density of the resin, wherein the projectile has average density less than the density of lead.

53 citations


Journal ArticleDOI
TL;DR: In this paper, a composite plate made of woven fabric CFRP, E-glass/epoxy, and Kevlar/E-epoxy composites is considered for high velocity impact.

53 citations


Journal ArticleDOI
TL;DR: In this article, the authors examined the evolution of unsteady cavitation around the shoulder and tail of a rigid projectile when it is vertically launched and demonstrated that the coupling effect between vibration deformation and collapse pressure is significant to enlarge the vibration amplitude.

48 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of high velocity impacts on carbon/epoxy tape quasi-isotropic laminates is studied and a simplified analytical model is proposed to identify different energy absorbtion mechanisms and predict the residual velocity of the projectile.
Abstract: In this work, the effect of high velocity impacts on carbon/epoxy tape quasi-isotropic laminates is studied. Experimental test were carried out at two different impact angles and in a wide range of velocities (from 80 to 490 m/s). Both parameters, the residual velocity and the damaged area, are used to evaluate the effect of the kinetic energy of the projectile on the laminate response. In addition it has been proposed a simplified analytical model which allows to identify the different energy absorbtion mechanisms and predict the residual velocity of the projectile. Finally the energy absorbed by the laminate during the impact is studied.

45 citations


Journal ArticleDOI
TL;DR: Based on large eddy simulation (LES) methodology, an approach was developed to simulate dynamic behaviors of cavitation, using k - mu transport equation for subgrid terms combined with volume of fluid (VOF) description of cavitations and the Kunz model for mass transfer.
Abstract: Cavitation generally occurs where the pressure is lower than the saturated vapor pressure. Based on large eddy simulation (LES) methodology, an approach is developed to simulate dynamic behaviors of cavitation, using k - mu transport equation for subgrid terms combined with volume of fluid (VOF) description of cavitation and the Kunz model for mass transfer. The computation model is applied in a 3D field with an axisymmetric projectile at cavitation number sigma = 0.58. Evolution of cavitation in simulation is consistent with the experiment. Clear understanding about cavitation can be obtained from the simulation in which many details and mechanisms are present. The phenomenon of boundary separation and re-entry jet are observed. Re-entry jet plays an important role in the bubble shedding.

45 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a 3D finite element analysis approach to study the penetration of a projectile into grouted concrete rock-rubble overlays considering the randomness of rock-Rubble in shape and distribution.

44 citations


Journal ArticleDOI
TL;DR: Over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold Velocity for penetration.
Abstract: Ballistic gelatin is frequently used as a model for soft biological tissues that experience projectile impact. In this paper we investigate the response of a number of gelatin materials to the penetration of spherical steel projectiles (7 to 11mm diameter) with a range of lower impacting velocities (<120m/s). The results of sphere penetration depth versus projectile velocity are found to be linear for all systems above a certain threshold velocity required for initiating penetration. The data for a specific material impacted with different diameter spheres were able to be condensed to a single curve when the penetration depth was normalised by the projectile diameter. When the results are compared with a number of predictive relationships available in the literature, it is found that over the range of projectiles and compositions used, the results fit a simple relationship that takes into account the projectile diameter, the threshold velocity for penetration into the gelatin and a value of the shear modulus of the gelatin estimated from the threshold velocity for penetration. The normalised depth is found to fit the elastic Froude number when this is modified to allow for a threshold impact velocity. The normalised penetration data are found to best fit this modified elastic Froude number with a slope of 1/2 instead of 1/3 as suggested by Akers and Belmonte (2006). Possible explanations for this difference are discussed.

Journal ArticleDOI
TL;DR: In this paper, a conical nose projectile made of steel was accelerated into a transparent soil target at an impact velocity of 13.6 m/s, and the complete penetration event was recorded using a high-speed digital camera.
Abstract: This paper presents a novel physical modelling method to study projectile penetration problems. The method employs a recently developed transparent synthetic soil made of oil-saturated fused quartz, which represents the macroscopic behaviour of silica sand. Digital image correlation (DIC, also known as particle image velocimetry (PIV)) techniques were employed to quantify the response of granular soils to high-speed penetration, non-intrusively. A conical nose projectile made of steel was accelerated into a transparent soil target at an impact velocity of 13.6 m/s. Visualisation of the soil deformation was made possible by means of a novel seeded plane within the transparent soil model. The complete penetration event was recorded using a high-speed digital camera. The captured images were analysed using DIC, and further analysis of displacement trajectories and strains were also carried out using in-house algorithms.

Journal ArticleDOI
TL;DR: In this paper, the authors examined data from two sets of penetration experiments that recorded deceleration during penetration into concrete targets with compressive strengths of 23 and 39 MPa, and developed two empirical penetration models that described decelerations versus displacement and specific kinetic energy (kinetic energy divided by projectile mass) versus displacement for the rigid-body response of the projectile.
Abstract: We examined data from two sets of penetration experiments that recorded deceleration during penetration into concrete targets with compressive strengths of 23 and 39 MPa. The 76.2-mm-diameter, 3.0 caliber-radius-head (CRH), 13 kg projectiles were machined from 4340 Rc 45 steel and contained a single-channel, 15 kHz acceleration data recorder. The data recorder was fitted into a circular hole in the solid nose of the projectile, so during penetration the accelerometer mounted in the data recorder measured structural responses as well as rigid-body projectile deceleration. Since the deceleration data were limited to 15 kHz, higher frequency responses were not measured. Furthermore, there are no available internationally accepted calibration procedures for accelerometers. Because of these complications, we present a method to correct the deceleration data so that an integration of the deceleration data agreed with the measured striking velocity. These corrections were small, and a double integration of the corrected deceleration was in good agreement with the measured depth of penetration. In addition, we developed two empirical penetration models that described deceleration versus displacement and specific kinetic energy (kinetic energy divided by projectile mass) versus displacement for the rigid-body response of the projectile. Data and model predictions showed that the deceleration-displacement response could be closely approximated by a linear rise with a depth of two projectile diameters followed by a region with constant deceleration until the projectile came to rest. Specific kinetic energy-displacement data and model predictions showed a nearly constant slope after the entry region, and this slope is the magnitude of the constant deceleration. Predictions from both methods closely agree with each other and the deceleration data.

Journal ArticleDOI
TL;DR: In this paper, the influence of key parameters, like interface strength and friction, on the ballistic limit of a ceramic-composite panel was studied, and a proper set of interface parameters is able to maximize the specific energy absorption of the panel.
Abstract: Ceramic-composite panels are acknowledged to provide effective impact protection even against small fragments and armour piercing projectiles. Nature shows similar solutions, coupling an hard face and soft backing layers, in dermal animal armours for protection against predators. Finite element simulations of impact on ceramic-composite panels, to evaluate their energy absorption capability, are presented. The influence of key parameters, like interface strength and friction, on ballistic limit is studied. We find that a proper set of interface parameters is able to maximize the specific energy absorption of the panel: although this optimum is variable case by case depending on projectile penetrability and target configuration, general guidelines are provided. Oblique impact results in a higher ballistic limit also thanks to projectile change in trajectory, providing interesting spots for future developments. Numerical results are compared with experimental data from literature and forecasts of analytical models.

Journal ArticleDOI
TL;DR: In this paper, the effects of thickness and stacking sequence of GLARE 5 (2024-T3 aluminum alloy-unidirectional S2-glass/epoxy) fiber laminated (FML) plates subjected to ballistic impact were examined.
Abstract: This two-part article examines the effects of thickness and stacking sequence of GLARE 5 (2024-T3 aluminum alloy-unidirectional S2-glass/epoxy) fiber–metal laminated (FML) plates subjected to ballistic impact Part I presented experimental observations of damage development in the specimens, C-scan damage contours, projectile velocity profiles and ballistic limit velocities (V50) Part II concerns with finite element (FE) modeling of the FML plates The 3D FE code, LS-DYNA, was used to model and validate the experimental results Experimentally obtained incident projectile impact velocity versus the residual velocity (Vi∼Vr), damage patterns and bullet residual length were used to validate the FE model Good agreement was achieved between experimental and numerical results It was found that for a given specimen thickness/stacking-sequence, by increasing the projectile incident velocity up to its V50 value, the maximum contact force increased By further increasing the projectile velocity above its V50, t

Journal ArticleDOI
TL;DR: In this paper, numerical simulations of low-speed impacts into granular materials using different projectile shapes under Earth's gravity were performed, and the authors compared the amounts of ejected mass obtained in their simulations with what was found in experiments that used similar setups.

Journal ArticleDOI
TL;DR: In this paper, the authors present results of five hypervelocity MEMIN impact experiments (Poelchau et al., 2013) using the Cr-V-Co-Mo-W-rich steel D290-1 as projectile and two different silica-rich lithologies (Seeberger sandstone and Taunus quartzite) as target materials.

Journal ArticleDOI
TL;DR: In this paper, the trajectories of dense projectiles subjected to gravity and drag at large Reynolds number were studied and it was shown that if the initial velocity is smaller than the terminal velocity of free fall, the projectile decelerates with an asymmetric trajectory first drawn by Tartaglia, which ends with a nearly vertical fall, as if a wall impeded the movement.
Abstract: We study the trajectory of dense projectiles subjected to gravity and drag at large Reynolds number. We show that two types of trajectories can be observed: if the initial velocity is smaller than the terminal velocity of free fall, we observe the classical Galilean parabola: if it is larger, the projectile decelerates with an asymmetric trajectory first drawn by Tartaglia, which ends with a nearly vertical fall, as if a wall impeded the movement. This regime is often observed in sports, fireworks, watering, etc. and we study its main characteristics.

Journal ArticleDOI
TL;DR: In this article, a fractional differential equation describing the behavior of a two-dimensional projectile in a resisting medium was proposed, where an auxiliary parameter k was introduced in the derivative operator to maintain the dimensionality of the physical quantities in the system, characterizing the existence of fractional time components in the given system.
Abstract: In this paper we propose a fractional differential equation describing the behavior of a two dimensional projectile in a resisting medium. In order to maintain the dimensionality of the physical quantities in the system, an auxiliary parameter k was introduced in the derivative operator. This parameter has a dimension of inverse of seconds (sec)−1 and characterizes the existence of fractional time components in the given system. It will be shown that the trajectories of the projectile at different values of γ and different fixed values of velocity v 0 and angle θ, in the fractional approach, are always less than the classical one, unlike the results obtained in other studies. All the results obtained in the ordinary case may be obtained from the fractional case when γ = 1.

Journal ArticleDOI
TL;DR: In this article, a 2D Digital Image Correlation (DIC) technique based on customized interpolation functions is presented for the measurement of spherical impactor positions, velocities and acceleration (translations and rotations) during medium velocity impact experiments performed with gas-gun devices.
Abstract: This paper deals with the measurement of spherical impactor positions, velocities and acceleration (translations and rotations) during medium velocity impact experiments performed with gas-gun devices. A dedicated 2D Digital Image Correlation (DIC) technique based on customized interpolation functions is presented. The proposed method considers the rotations of the projectile which a standard subset-based DIC technique would undoubtedly have difficulty managing. Emphasis is placed on metrological performance and various validations are proposed. Measurements are additionally compared to those retrieved with conventional techniques. This DIC method provides a precise quantification of projectile motion and impact loads during gas-gun tests with a single high speed camera.

Patent
15 May 2014
TL;DR: In this article, the authors present a system for detecting a hit by a BB pellet, such as a BB-penetrator, in a robot game and a processor to determine whether a hit has occurred.
Abstract: A sensing apparatus may be provided capable of detecting a hit by a projectile, such as a BB pellet. The sensing apparatus may include a surface and accelerometer to detect the acceleration of the surface. A processor may determine whether a projectile hit has occurred. The sensing apparatus may be mounted onto a vehicle. The vehicle may be a robot capable of participating in a game. The robot game may occur within a facility.

Journal ArticleDOI
TL;DR: In this paper, a class of dual-spin-stabilized canards equipped with canards in atmospheric flight is studied, and the spin-rate properties of the forward and aft bodies of the canards are investigated.
Abstract: To develop the guided spin-stabilized projectiles with high hit precision, a class of dual-spin-stabilized projectiles equipped with canards in atmospheric flight is studied. The work reported here focuses on the spin-rate property for the forward and aft bodies of this projectile as well as the coupled effect between the two bodies. By taking into account the distinctive spin rates of the two bodies, the mathematical model of motion around the center of mass was established. The variation law of spin rates, several influencing factors, and the induced change in ballistic drift and angle of attack were analyzed through numerical trajectory simulation. To validate the numerical results, both the simplified and coupled analytical solutions for spin rates were obtained by solving the dynamic model analytically under different conditions. Both the numerical and analytical results indicate that the spin-rate property is influenced by the canards actuation, the ratio of the moment of inertia, and the connected ...

Journal ArticleDOI
TL;DR: In this article, the vertical water-entry behavior of bullet-shaped projectiles was experimentally and theoretically studied, and a theoretical model was developed based on the solution to the Rayleigh-Besant problem to describe the evolution of the cavity shape.
Abstract: The vertical water-entry behavior of bullet-shaped projectiles was experimentally and theoretically studied. Particular attention was given to characterizing projectile dynamics, the resultant evolution of air cavity and particularly surface closure before deep closure in the moderate speed. We developed equations for the projectile motion with significant and negligible gravitational effects. Based on the solution to the Rayleigh-Besant problem, a theoretical model was developed to describe the evolution of the cavity shape, including the time evolution of the cavity on fixed locations and its location evolutions at fixed times. The gravitation effects during the initial stage of the impact of the projectile on the water can be ignored, but those during the later stage should be considered, many literatures do not have the report of this aspect. The theoretical predictions were consistent with the experimental observations. The evolution of air cavity had a significant effect on ballistic stability.

Journal ArticleDOI
TL;DR: In this article, the sabot discard behavior after projectile ejection from the muzzle is investigated at Mach number 4.0 and angle of attack of 0°, and 3D compressible equations implemented with a dynamic unstructured tetrahedral mesh are numerically solved with a commercial computational fluid dynamics (CFD) code (FLUENT 12.0).
Abstract: The sabot discard process of an armor-piercing, fin-stabilized discarding sabot (APFSDS) is crucial for the flight stability of the projectile. In this paper, the sabot discard behavior after projectile ejection from the muzzle is investigated at Mach number 4.0 and angle of attack of 0°. 3D compressible equations implemented with a dynamic unstructured tetrahedral mesh are numerically solved with a commercial computational fluid dynamics (CFD) code (FLUENT 12.0). Six-degrees-of-freedom (6DOF) rigid-body motion equations is solved with the CFD results through a user-defined function to update the sabot trajectory at every time step. A combination of springbased smoothing and local re-meshing is employed to regenerate the meshes around the sabot and describe its movement at each time step. Computational results show three different separation processes during the sabot discard process. Furthermore, the aerodynamic forces of APFSDS are calculated, and the trajectories of the three sabots are illustrated through the numerical solution of 6DOF equations. The results of the present study agree well with typical experimental results and provide detailed parameters that are important for analyzing the stability of the projectile. The present computations confirm that the numerical solution of the governing equations of aerodynamics and 6DOF rigid-body equations are a feasible method to study the sabot discard processes of APFSDS.

Journal ArticleDOI
TL;DR: In this paper, a dynamic overlapped grids approach was applied to deal with the problems of a high-speed moving base bleed projectile and the rapid depressurization process in the combustion chamber of base bleed unit.

Journal ArticleDOI
TL;DR: In this article, a 3D dynamic finite element analysis (FEA) was performed to study the transient stress distribution of adhesively-bonded joints under solid projectile impact.

Journal ArticleDOI
TL;DR: In this article, a composite bonnet liner subject to a high-velocity (70 m/s), low-energy (<300 J) impact by a 50mm-diameter projectile was investigated using computational simulation and by experiment.
Abstract: A composite bonnet liner subject to a high-velocity (70 m/s), low-energy (<300 J) impact by a 50-mm-diameter projectile has been investigated using computational simulation and by experiment High-

Journal ArticleDOI
TL;DR: In this paper, the configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through super-cavitating projectile approach, experimentally and numerically.
Abstract: The configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through supercavitating projectile approach, experimentally and numerically. The projectile was projected vertically into water and aqueous solution of CTAC with weight concentrations of 100, 500, and 1000 ppm, respectively, using a pneumatic nail gun. The trajectories of the projectile and the supercavity configuration were recorded by a high-speed CCD camera. Besides, water entry supercavities in water and CTAC solution were numerically simulated based on unsteady RANS scheme, together with application of VOF multiphase model. The Cross viscosity model was adopted to represent the fluid property of CTAC solution. It was obtained that the numerical simulation results are in consistence with experimental data. Numerical and experimental results all show that the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coe...

Journal ArticleDOI
TL;DR: In this paper, the phase angle in the interference term is determined primarily by the projectile momentum transfer rather than by the recoil-ion momentum, and the interference observed in the data is not primarily due to a two-center effect.
Abstract: We report on a kinematically complete experiment on ionization of ${H}_{2}$ by proton impact. While a significant impact of the projectile coherence properties on the scattering-angle dependence of double-differential cross sections (DDCSs), reported earlier, is confirmed by the present data, only weak coherence effects are found in the electron and recoil-ion momentum dependence of the DDCSs. This suggests that the phase angle in the interference term is determined primarily by the projectile momentum transfer rather than by the recoil-ion momentum. We therefore cannot rule out the possibility that the interference observed in our data is not primarily due to a two-center effect.

Journal ArticleDOI
TL;DR: In this paper, a two-stage light-gas gun was used to launch AISI 52100 steel spherical projectiles and 30-mm diameter, 15-mm long graphite targets.