Projectile Penetration Research Articles

Numerical Models for Simulating the Dynamic Behavior of Concrete Subjected to High Velocity Impact

To solve high velocity impact problems, such as projectile penetration and blasting, a numerical model should be established that can account for the mechanical behavior of materials under dynamic loading. The numerical model should include both the equation of state of materials, which describes the state of the materials under given loading conditions, and constitutive equations for material failure and damage. In this paper, we introduced numerical models for simulating the dynamic behavior of concrete under high velocity impact and the determination of associated parameters, and described the applicability of these models to rock mass modeling.

A SPH-Lagrangian-Eulerian Approach for the Simulation of Concrete Gravity Dams under Combined Effects of Penetration and Explosion

The damage prediction of high dams under the attacks of earth-penetrating weapons has gained significant importance in recent years. For this purpose, a SPH-Lagrangian-Eulerian coupled approach is proposed to describe the damage processes of concrete gravity dams subjected to the combined action of the penetration and explosion. The SPH method is used to model the concrete material with the large deformation near the penetration and explosion regions. The Lagrangian algorithm is adopted to simulate the high-velocity projectile and dam body with the small distortion. And the Eulerian algorithm is employed to describe the dynamic behavior of the water and air media. The validity of the penetration model is calibrated against a previous penetration test. Meanwhile, the SPH-Lagrangian-Eulerian coupled method is verified by implementing an underwater explosion test in a concrete cube. The computed distribution of cracking damage is consistent with the result of the experimental test, which validates the validity of the proposed SPH-Lagrangian-Eulerian coupling method. Subsequently, the penetration processes of a concrete gravity dam under the high-velocity projectile are presented. After the rapid penetration, the explosives are detonated in the dam with the initial penetration damage. The shock wave propagation characteristics in the dam and reservoir water are discussed. The failure processes and dynamic responses of the dam subjected to the combined action of the penetration and explosion are investigated. The influence of the initial penetration damage and the reservoir water on the failure processes of the dam subjected to the internal blast loading is also discussed. The results show that the penetration of the high-velocity projectile only causes a local damage to the concrete gravity dam. However, the combined effects of the penetration and explosion cause significantly more damage to the upper region of the dam.

Penetration resistance of ultra-high-strength concrete protected with layers of high-toughness and lightweight energy absorption materials

Aluminium foam has advantages of excellent shock absorption, cyclic utilization, and lightweight. Ultra-high-molecular-weight polyethylene (UHMWPE) fibre has a low density, a high specific strength, a high modulus and a great capability in energy absorption. Steel wire mesh has high toughness and elongation properties and a good effect on energy absorption. In the present study, UHMWPE fibre, steel wire mesh and aluminium foam were used to protect ultra-high-strength concrete (UHSC) targets to resist DT300 high-strength alloy-steel projectile penetration with striking velocities from 550 m/s to 800 m/s. High-speed impact tests on normal-strength concrete (NSC) targets were also conducted for comparison. Testing results including the failure mode, depth of penetration (DOP), crater dimensions and damage area of protected concrete targets, indicate that the new composite material protective cover has an outstanding performance in the shock wave absorption, especially in reducing the crack propagation and debris spatter of protected UHSC targets, as well as increasing the deviation angles of projectile terminal ballistic trajectories. It is a successful demonstration of anti-penetration properties research for new concrete composite structures.

Three-dimensional woven carbon fibre polymer composite beams and plates under ballistic impact

Clamped rectangular orthogonal 3D woven carbon composite beams under ballistic impact at a velocity range 60ms-1⩽v0⩽190ms-1 were investigated in order to understand the damage mechanisms within the material and the role of through-the-thickness (TTT) reinforcement. Experimental tests revealed three distinct categories of beam response: (i) low velocity impacts (v0<110ms-1) which featured projectile rebound, with dominant matrix cracking and localised fibre fracture, (ii) medium velocity impact (110ms-1⩽v0<148ms-1) which exhibited a stretch-deformation dominated failure mechanism, and (iii) higher velocity impacts (v0⩾148ms-1) which resulted in projectile penetration, combined with longitudinal fibre fracture at the centre of the sample. Finite element (FE) simulations were conducted to understand the experimental outcomes, which showed sufficient fidelity and captured the three distinct beam response regimes. The presence of the TTT-reinforcement can suppress the inter-laminar matrix crack propagation and increase the material ballistic impact resistance for low velocity impact and high velocity impact. However, for medium velocity impact, the in-plane fibre fracture surface was found to be at the locations of TTT-reinforcement. This may suggest that the TTT-reinforcement creates weak points for the stretch-deformation dominated failure mechanism. The verified FE simulations were conducted to predict the multi-hit ballistic impact limit surfaces for the clamped circular 3D woven composite plates, and for the equivalent laminate composite without the presence of the TTT reinforcement. The numerical results suggested the presence of TTT reinforcement could improve the multi-hit ballistic resistance of the composite plates for multi-hit scenarios where the initial impact is 50%–95% of the ballistic limit of the plates.

Ballistic Impact Performance Study on Thermoset and Thermoplastic Composites

Ballistic impact-resistant materials are of interest for the past few decades. Ballistic impact is a high-velocity impact where the target material is perforated by the projectile, such as a bullet hitting on a surface. In this study, the effect of ballistic impact on thermoset composites, Kevlar–Epoxy, Carbon–Epoxy, Glass–Epoxy, and thermoplastic composite, Carbon–Polyetheretherketone, was done. Projectile residual velocity and projectile penetration depth were used to quantify the effectiveness of the composite material to resist perforation. The simulation study was done on ABAQUS-6.13. The study included preliminary fiber orientation studies and selection of the best performing composite with the most effective fiber orientation. Further, the selection of the best performing target material was done by varying target thickness and projectile velocity. In this study, high-performance Carbon–Polyetheretherketone composite showed the most impact resistance.

Water Ice Radiolytic O2, H2, and H2O2 Yields for Any Projectile Species, Energy, or Temperature: A Model for Icy Astrophysical Bodies

AbstractO2, H2, and H2O2 radiolysis from water ice is pervasive on icy astrophysical bodies, but the lack of a self‐consistent, quantitative model of the yields of these water products versus irradiation projectile species and energy has been an obstacle to estimating the radiolytic oxidant sources to the surfaces and exospheres of these objects. A major challenge is the wide variation of O2 radiolysis yields between laboratory experiments, ranging over 4 orders of magnitude from 5 × 10−7 to 5 × 10−3 molecules/eV for different particles and energies. We revisit decades of laboratory data to solve this long‐standing puzzle, finding an inverse projectile range dependence in the O2 yields, due to preferential O2 formation from an ~30 Å thick oxygenated surface layer. Highly penetrating projectile ions and electrons with ranges ≳30 Å are therefore less efficient at producing O2 than slow/heavy ions and low‐energy electrons (≲ 400 eV) which deposit most energy near the surface. Unlike O2, the H2O2 yields from penetrating projectiles fall within a comparatively narrow range of (0.1–6) × 10−3 molecules/eV and do not depend on range, suggesting that H2O2 forms deep in the ice uniformly along the projectile track, e.g., by reactions of OH radicals. We develop an analytical model for O2, H2, and H2O2 yields from pure water ice for electrons and singly charged ions of any mass and energy and apply the model to estimate possible O2 source rates on several icy satellites. The yields are upper limits for icy bodies on which surface impurities may be present.

Penetration of Rigid Projectile into Concrete Target with Effect of Attack Angle: Theory and Experiment

The existing prediction methods of penetration depth do not take the influence of attack angle or angular velocity of projectile (i.e. effect of attack angle) into account. The main purpose of this work is to develop an approximate approach to predict the penetration depth for a rigid projectile into concrete target covered with yaw-inducing overlays. A quasi-static, elastic–plastic contact model of projectile impacting on irregular barrier is built based on Hertz’s contact theory, and the expression of effect of attack angle are also presented. The stress on projectile–target interface is derived according to spherical cavity expansion model and mechanical property of target, where reduction coefficient is introduced to consider the effect of free surface, and the penetration resistances are further obtained. Differential equations of motion for projectile arbitrarily oblique into target covered with yaw-inducing overlays are given by employing the initial conditions of projectile striking on irregular barrier. Then a simplified formula of depth-of-penetration (DOP) with effect of attack angle is presented by introducing an influence coefficient of oblique impact and an influence coefficient of yaw-inducing overlays into the depth of normal penetration. Predictions from the simplified formula are validated by comparison with ballistic experimental data for a 57[Formula: see text]mm diameter, 4.44[Formula: see text]kg, and ogive-nose, semi-armor-piercing with striking velocities between 320 and 705[Formula: see text]m/s.

Numerical modeling of the elastoplastic damage behavior of dry and saturated concrete targets subjected to rigid projectile penetration

SummaryThe objective of the present paper is to present a numerical study on the penetration performance of concrete targets with 2 different water contents. Numerical analysis has been performed by using the finite element code Abaqus/Explicit, in which a coupled elastoplastic damage model has been developed for saturated/unsaturated concrete under a wide range of confining pressures. The performance of proposed model has been firstly verified by simulating the triaxial compression tests and penetration tests realized with saturated/dry concretes. Comparisons of available experimental results and numerical simulations show that the proposed model is able to reproduce satisfactorily the mechanical behavior of saturated and dry concretes. A higher failure stress and a more important pores closing are generally obtained in dry concrete samples with respect to saturated ones. Furthermore, the main observed patterns of penetration test realized with saturated concrete targets are also satisfactorily simulated by the numerical results. Therefore, the proposed model is used to numerically predict the penetration performance of dry concrete target, and the penetration performance of dry/saturated concrete target is discussed. We observe that in dry concrete target, the penetration of projectile is strongly declined, and a smaller damage zone is created. The numerical predictions and discussions can help engineers to enhance their understandings on the influence of hydraulic conditions on structural vulnerability of concrete structures subjected to near‐field detonations or impacts.

Analytical and numerical investigations on the penetration of rigid projectiles into the foam core sandwich panels with aluminum face-sheets

The aim of this study was to evaluate the penetration of ballistic projectiles into the sandwich panels both analytically and numerically. Due to the complexity of the mathematical equations governing this phenomenon, very few analytical studies have been conducted in this area. Given the widespread use of sandwich panels consisting of metal face-sheets and metal foam core in aerospace industries, revisions are carried out on analytical method provided by Hoo Fatt et al. on polymer foam core and composite face-sheets sandwich panels. Then using the improved relations, the high speed impact of a cylindrical projectile on the sandwich panels with aluminum face-sheets and aluminum foam core with different density ratios has been discussed. Also, the penetration process is simulated and finally to evaluate the accuracy of the improved analytical method and simulations, the results are compared to the experimental data obtained from tests have been done on the panels with aluminum foam core and aluminum face-sheets. Results of the research show that the improved procedure and numerical simulations are in good agreement with the experiments.

Reprint of: A new simplified analytical model for soil penetration analysis of rigid projectiles using the Riemann problem solution

A new simplified analytical model to analyze the penetration of rigid projectiles into soil media is presented. The soil medium is represented by a set of discs, responding in the radial direction under plain strain conditions. A convenient mathematical formulation is derived based on some simplifying assumptions. According to the present approach, the contact parameters in each disc are computed using the developed exact solution of the symmetrical Riemann problem for an irreversible compressible medium. One of the new features of the present model is the incorporation of the exact nonlinear equation of state including unloading-reloading thus considering another key variable that is the maximum medium density that is attained in the process of active loading before unloading is started. Thus the new model considers unloading in the soil medium during the progress of penetration. The present model focuses on the projectile motion and provides information on its velocity, deceleration and depth time histories. It also provides information on the interaction of the projectile with the surrounding soil such as the normal stress distribution along the projectile nose and is capable of determining the contact zone between the nose and the soil. Comparison of the present model results with two-dimensional numerical results as well as with different analytical models and with experimental data is performed. The present model predictions are found to be in good agreement with test data and superior to many existing simplified models. Contrary to many other simplified models, the present model is purely theoretical and does not require any empirical constants or special arbitrary assumptions for calculation of the contact pressures along the projectile nose at all times. The calculations require very small computer time and provide much information regarding the projectile motion in the soil medium.

Shock Propagation Effects in Multilayer Assembly Including a Liquid Phase

During a ballistic impact, the protective material that plays the role of armour has to dissipate the kinetic energy in order to limit the projectile penetration in the target. Our aim is to emphasis on the role played by a liquid-filled system on the impact energy mitigation due to cavitation inception and later bubble expansion. To observe this, small scale experiments have been carried out on a three layers sample (Aluminium-Water-PMMA) submitted to shock waves induced by laser impact applied on the Al face. Rapid camera visualizations allow reproducing, at small scale, the effects of projectiles on armours for various monitored impact energies. We observe the formation of bubbles for sufficiently intense impacts due to traction effects in the water caused by the multiple reflections of waves within the sample. The cavitation threshold of water under dynamic loading is then experimentally investigated for two samples: one with 600 μm thick Al / 400 μm of water and 3 mm of PMMA, the other with 1000 μm thick Al / 1600 μm of water and 3 mm of PMMA. Using dimensional analysis, we show that the energy taken during the process of inception and bubble expansion becomes more important as the energy of the impact increases.

Влияние сжимаемости снаряжения на параметры его состояния при проникании ударника в бетонную преграду

Влияние сжимаемости снаряжения на параметры его состояния при проникании ударника в бетонную преграду

Crater Formation on High-Velocity Collision of a Metallic Projectile with Polymethylmethacrylate Targets

The possibility of using targets made of polymethylmethacrylate for determining the velocity of metallic projectiles is considered. Results of experimental investigations of the interaction of single spherical steel particles of diameter 2.5 mm with polymethylmethacrylate targets in the velocity range 0.94–2.4 km/s are presented. The acceleration of particles is achieved with the aid of a light-gas magnetoplasma launcher. A semiempirical dependence of the depth of penetration of steel projectiles into a polymethylmethacrylate target on the collision velocity has been obtained.

Rigid projectile penetration into a concrete medium: A new model

A new simplified model to analyze the penetration of a rigid projectile into a concrete thick medium is presented. The concrete medium is modeled by a set of discs, responding in the radial direction under plain strain conditions. A convenient mathematical formulation is derived based on some simplifying assumptions. A major new feature of the present model is that it hybridizes two different analytical and numerical approaches that have been developed by the authors. In the present model, the Riemann problem exact solution is applied to the interaction of the projectile nose tip with the target. It is assumed that when the nose tip meets a new undisturbed disc, loading occurs during its interaction with the concrete, and therefore the unloading branch of the equation of state is not required in the Riemann problem. The other discs that maintain contact with the projectile nose and had been loaded in earlier time steps undergo unloading, and a special approach has been developed to compute their contact stresses. This entirely new formulation has not been proposed earlier. The present model enables calculations of the projectile motion time history (i.e. deceleration, velocity, and depth). Comparison of the present model results with experimental data shows very good agreement. Contrary to many other simplified models, the present approach does not require any empirical constants or any preliminary assumptions concerning the contact pressures acting on the penetrating projectile nose, as other models do. Computer time of less than 1 min is needed for a complete analysis.

Hemispherical nosed steel projectile high-speed penetration into aluminum target

Terminal ballistic performance of high-strength projectiles penetrating into metallic targets is mostly concerned by both weapon and armor designers. Most existing works are concentrated on the rigid-eroding penetration regime, and limited studies have addressed the rigid-deforming-eroding penetration regime. In this paper, nineteen shots of hemispherical nosed D6A steel projectiles penetration test on 5A06-H112 aluminum targets is conducted with a wide range of velocities (696m/s–1870m/s). The non-monotonic dependence of depth of penetration (DOP) on the impact velocity is observed, which successively corresponds to the three penetration stages, i.e., rigid projectile penetration, deforming projectile penetration without eroding and eroding projectile penetration. Then, for the non-monotonic rigid-deforming-eroding projectile penetration regime, the applicability of the existing six classical theoretical models for both rigid and eroding projectile penetrations is evaluated. Furthermore, the transition velocities (the upper limit of rigid penetration and the lower limit of eroding penetration) are discussed and an empirical judgement criterion for the occurrence of non-monotonic dependence is proposed. Finally, by conducting the dynamic compression test, quasi-static tension test under varying temperature, etc., the Johnson-Cook model parameters for the present target and projectile are calibrated and validated by numerically simulating the present test.

Parameters of Holmquist–Johnson–Cook model for high-strength concrete-like materials under projectile impact

Holmquist–Johnson–Cook constitutive model has been widely used in analyzing the dynamic responses of concrete-like materials under projectile impact and explosive loadings, the constitutive parameters of which were always referred from the original documents and only applied to the normal strength concrete with the compressive strength of 48 MPa. Aiming to confirm the Holmquist–Johnson–Cook model parameters for high-strength concrete-like materials (compressive strength ≥60 MPa), based on the available test data from the quasi-static uniaxial compression, triaxial compression, Split-Hopkinson pressure bar, as well as the Hugoniot experiments, the strength parameters, the strain rate parameter, and the equation of state parameters of Holmquist–Johnson–Cook model for high-strength concrete-like materials are determined. Using the finite element program LS-DYNA, total eight sets of projectile penetration and perforation tests on high-strength concrete (uniaxial compressive strengths of 67.5–157 MPa) and high-strength rock targets (uniaxial compressive strengths of 60 and 154 MPa) are numerically simulated, respectively. By comparisons with the test data of penetration depths and residual velocities of the projectiles, the verifications of the proposed parameters are validated, which provides the reference for the design of protective structures.

Finite Element Simulation of Cylindrical Projectile Penetrating Composite Laminate

Composite material has been widely used in the field of bulletproof, and many people have studied it. With the development of the large commercial finite element software, it provides a broad platform for the research of the bullet proof performance of the composite material. The finite element software is used to simulate the effect of different factors on the ballistic performance. The dynamics simulation model of orthotropy is established by Abaqus/Explicit Hashin damage criterion. The velocity of the projectile is changed with time in the process of penetrating the composite target. The theoretical and numerical simulation of the ballistic limit velocity of projectile penetration are compared by the simulation of the composite laminate. The simulation results agree well with the theoretical calculations, and the model is proved to be reasonable and effective. It provides a good basis for the study on the damage of fiber reinforced composite target

Penetration of fast projectiles into resistant media: From macroscopic to subatomic projectiles

The penetration of a fast projectile into a resistant medium is a complex process that is suitable for simple modeling, in which basic physical principles can be profitably employed. This study connects two different domains: the fast motion of macroscopic bodies in resistant media and the interaction of charged subatomic particles with matter at high energies, which furnish the two limit cases of the problem of penetrating projectiles of different sizes. These limit cases actually have overlapping applications; for example, in space physics and technology. The intermediate or mesoscopic domain finds application in atom cluster implantation technology. Here it is shown that the penetration of fast nano-projectiles is ruled by a slightly modified Newton’s inertial quadratic force, namely, F∼v2−β, where β vanishes as the inverse of projectile diameter. Factors essential to penetration depth are ratio of projectile to medium density and projectile shape.

Experimental and numerical study of reactive powder concrete reinforced with steel wire mesh against projectile penetration

This paper presents experimental and numerical studies on impact resistance of reactive powder concrete (RPC) targets reinforced with 44-layer steel wire meshes. Steel ogive-nosed projectiles with an average mass of 330g and striking velocities ranging from 550m/s to 800m/s were launched against the cylindrical RPC targets with 750mm diameter and 700mm thickness. The impact responses observed in the tests, including depth of penetration (DOP), crater diameter and volume loss, were investigated and discussed, which indicates an effective impact resistance of steel wire mesh reinforced RPC in comparison with the previous studies on ultra-high performance based cement composites (UHPCC) with additions of fibres and basalt aggregates. Numerical studies based on validated material and element models are also conducted to simulate the impact responses of reinforced RPC targets against high-velocity projectile penetration in explicit hydro-code LS-DYNA. The impact responses, especially for the DOP, are well predicted by using the numerical models. Moreover, further investigation based on the verified numerical models is discussed in the present paper to explore the influence of mechanical and physical properties of steel wire mesh reinforcement on the resistance of projectile penetration.

Experimental study on the penetration effect of ceramics composite projectile on ceramic / A3 steel compound targets

Abstract In order to improve the penetration of projectiles into ceramic composite armors, the nose of 30 mm standard projectile was replaced by a toughened ceramic nose, and the performance of ceramic-nose projectiles penetrating into ceramic/A3 steel composite targets has been experimentally researched. According to impact dynamics theory,, the performances of 30 mm ceramic-nose projectile and 30 mm standard projectile penetrating into the ceramic/A3 steel composite targets were analyzed and compared using DOP method, especially focusing on the effects made by different nose structures and materials. The aperture and depth of perforation of projectile into the armor plates as well as the residual mass of bullet core under the same conditions were comparatively analyzed. A numerical simulation was built and computed by ANSYS/LS-DYNA. Based on the simulated results, the penetration performance was further analyzed in terms of the residual mass of bullet core. The results show that the ceramic nose has a great effect on the protection of bullet core.