High-velocity Projectile Impact Research Articles

A simulation approach for quantifying ballistic impact damage in ultra-high-performance concrete

In this work, we provide a hydrocode simulation model for high-velocity projectile impact against ultra-high-performance concrete targets and establish a methodology to extract damage quantities from the simulation results. In the parameter derivation process, published and own data stemming from material experiments, such as uniaxial, triaxial, and planar plate impact tests, are used as a starting point. To fill the systematic gaps of strength data for pressures of 1 GPa to 5 GPa and for fractured concretes, residual velocities of projectiles and qualitative target damage information from ballistic experiments with high-hard steel spheres are additionally used as a reference in parametric simulations. All criteria from the comparatively broad data basis are successfully reproduced by the simulation model simultaneously. The simulated damage quantities derived by the proposed extraction procedure are reasonable counterparts to the corresponding experimental measures from earlier published works, allowing a new quality of comparison between both worlds.

High-Velocity Projectile Impact Behaviour of Friction Stir Welded AA7075 Thick Plates

High-Velocity Projectile Impact Behaviour of Friction Stir Welded AA7075 Thick Plates

High-velocity penetration impact characteristics of fiber metal hybrid cylindrical shells: Theoretical and experimental investigation

The high-velocity penetration impact characteristics of fiber metal hybrid (FMH) cylindrical shells are investigated. A finite element (FE) model of such a shell subjected to an internal high-velocity projectile impact is established based on ABAQUS software to predict impact parameters, in which the impact damage failures of FRP, metal, and virtual cohesive layers are considered, respectively. Both literature and experimental results are utilized to verify the current model, with the influences of critical parameters on the residual velocity and specific energy absorption properties being discussed. The outputs provide valuable references for evaluating the high-velocity impact resistance of such structures.

Attenuation effect of a preset bubble on hydrodynamic ram induced by fragments impacting fluid-filled tank

When the fluid-filled structure is impacted by a high-velocity penetrator, the hydrodynamic ram (HRAM) will appear and may induce catastrophic damage. Based on the damage mechanism of HRAM, a countermeasure through presetting a bubble inside the fluid-filled tank is proposed to attenuate the HRAM loads and thus alleviate the vulnerability of the tank structure under the impact of high-velocity projectile. Experimental tests are performed to compare the tank’s damage considering the effect of bubble by the charge-driven preset fragments. The experimental results show that the peak pressure and impulse of the initial impact wave acting on the tank rear plate are reduced by 78% and 88%, respectively, and the cavitation collapsing pressure acting on the rear plate almost disappeared. Meanwhile, the maximum deformation of the front plate is reduced by about 15%. In addition, numerical simulation is employed to reproduce the experimental process. By comparing the structural dynamic response and the shock wave propagation process, the attenuation mechanism of the preset bubble on HRAM is revealed. Furthermore, the influence of the bubble position and size on the attenuation effect is investigated. Numerical results show that a smaller distance between the bubble and the front plate, and a larger bubble size lead to a better attenuation effect.

Graphene oxide coated silicon carbide films under projectile impacts

The quest for hybrid materials to withstand extreme loading conditions has been a canonical field of research over the past decades. As an emerging hybrid material, graphene oxide (GO)-silicon carbide (SiC) offers remarkable thermo-chemo-mechanical properties with applications in defense, energy, and aerospace engineering. Researches to unravel the various properties of the aforementioned material subjected to different loading conditions have been on the rise to further promote its potential for the pertinent industries. Nonetheless, impact resistance characterization of such composite received less attention due to experimental and computational difficulties. Here, the aforementioned problem is investigated by leveraging ReaxFF molecular dynamics simulations. Accordingly, the response of 4H-SiC thin films coated by GO samples under indentation and high-velocity projectile impact is assessed. It is found that (a) composite films containing GO samples with higher oxidation degree demonstrate softer behavior under indentation, and (b) fracture pattern and penetration-resistance under high-velocity impact are contingent on the oxidation degree of the coating layers. In essence, impact-induced complete perforation is more localized to the impacted zone as oxidation degree of the coating layers increases. Therefore, oxidation content can be considered as a novel tuning factor for the fracture behavior of the GO-SiC thin films under projectile impacts. The influence of oxygen functional groups on the interaction energy between GO and SiC layers are also discussed. The findings of this study reveal some insights into the bottom-up design pathways for developing novel protective barriers in which GO is used as a coating layer or reinforcement for SiC ceramics.

High velocity impact response of sandwich structures with auxetic tetrachiral cores: Analytical model, finite element simulations and experiments

This paper investigates the energy absorption and deformation characteristics of sandwich structures with auxetic tetrachiral core under high velocity projectile impact. The finite elementmodel of the structure is developed using the Johnson-Cook material model and is used to studythe effects of projectile impacts forvelocities between150 and 450 m/s. TheFE model is validated usingin-houseexperiments on 3D printed PLA sandwich with tetrachiral core under hemispherical projectile impact and also using experimental datareported in the literature. Further, a semi-analytical model is developed to estimate the residual velocities and energy absorption of sandwich structure under blunt projectile impact, which shows good agreement with the FE results with an error of less than 8%. Finally, the performance of the sandwich structure with tetrachiral cores is studied under projectile impact for velocities ranging from 150 to 350 m/s and compared with sandwich structures with re-entrant and double arrowhead cores. The results show that for velocities above the ballistic limit, the energy absorbed by the facesheets, and core are nearly constant and is greatest for blunt projectile impact, followed by hemispherical, ogive, and conical geometries. Furthermore, sandwich structures with auxetic cores exhibit better energy absorption characteristics compared to those with hexagonal honeycomb cores.

High-velocity projectile impact resistance of reinforced concrete slabs with ultra-high performance concrete strengthening - A numerical study

This paper adopted numerical simulations to explore the high-velocity projectile impact (HVPI) performance of 180 mm thick reinforced concrete (RC) slabs with ultra-high performance concrete (UHPC) strengthening. Finite-element modelling of the RC slab and UHPC layer subjected to HVPI was firstly performed to verify the numerical model related to the local damage and projectile residual velocity. Then, the slab configuration parameters concerning the steel rebar layer number and grid size in the UHPC layer, the spacing between the RC slab and UHPC layer, and the layout positions of the UHPC layer were investigated to determine the optimal strengthening strategy to resist projectile perforation. The numerical results demonstrated that snugly placing the UHPC layer without steel rebars upon the impact face of the RC slab was the most effective and efficient strengthening strategy. With the optimal slab configuration, the influences resulting from the unconfined compressive strength of UHPC, projectile mass and nose shape on the projectile perforation of UHPC strengthened RC slabs were explored. For each influencing factor, the relations between the projectile residual velocity and UHPC layer thickness were obtained at various projectile striking velocities. In the light of the simulated data, an empirical formula was established to estimate the ballistic limit of the 180 mm thick RC slab with UHPC strengthening..

Dynamic structural responses of high-performance fiber-reinforced cement composites panels subjected to high-velocity projectile impact loadings

Dynamic structural responses of high-performance fiber-reinforced cement composites panels subjected to high-velocity projectile impact loadings

Laminated Glass Plates Subjected to High-Velocity Projectile Impact and Their Residual Post-Impact Performance

This study aims to analyze the performance of laminated glass against ballistic loading and investigates its residual load-bearing capacity. Two groups of specimens were used in quasi-static four-point bending experiments, first without prior ballistic damage and then with it. The main objective was to compare the load-bearing capacity of these two groups to see the effect of ballistic damage. Three different layer compositions were used. The ballistic loading was conducted using an in-service 9 mm bullet fired from a semiautomatic carbine with the glass specimens hanging on steel ropes in a free boundary setup. Numerical simulation and analytical methods were used and validated against the measured response of the undamaged specimens. The simulations were in good agreement with the experimental results. All of the glass specimens were able to withstand the ballistic loading, and the subsequent performance during the quasi-static bending loading was similar to that of the undamaged specimens. The quality of the glass edges seemed to be more important than ballistic damage. The front-plate damage played a negligible role, and the back-plate damage needed to be extensive to influence subsequent performance. Provided that ballistic damage is mainly localized only to the centers of the plates, it did not affect the post-impact loading capacity.

Mechanism of polyurea in protecting liquid-filled square aluminum tube from the impact of high-velocity projectile

The impact of projectile on liquid-filled containers produce hydrodynamic ram (HRAM), which results in local damage and overall deformation of the container. Aiming at enhancing the protection capability of liquid-filled containers under projectile impact loads, this study proposes a scheme of spraying polyurea on liquid-filled containers. Calibrated numerical modeling with an experiment was conducted to investigate the dynamic response process of the polyurea coated water-filled square aluminum tube (PCST) under the high-velocity impact of projectile. The effects of projectile velocity (700–1100 m/s) and polyurea thickness (0–6 mm) on the damage characteristics of the liquid-filled containers were analyzed and summarized. Results showed that the strength of HRAM increased with the rise initial velocity of the projectile. The polyurea layer reduced the plastic deformation of the square aluminum tube, restricted the crack expansion of the corner, and wrapped the petaling failure of the tube. The restraining action of the polyurea coating on the deformation of the container enhanced the peak pressure in the liquid, whereas the deceleration of the polyurea layer on the projectile weakened the deformation of the tube. A competitive relationship existed between the restraining action of the container and the deceleration effect of the projectile on HRAM. With the increase in polyurea layer thickness, the strength of HRAM trended to initially increase and then decrease. The leading cause of HRAM was gradually changed from container restraint action to projectile deceleration effect.

Perforation studies of concrete panel under high velocity projectile impact based on an improved dynamic constitutive model

The finite-depth concrete panels have been widely applied in the protective structures, and its impact resistance and dynamic fracture failures, especially the scabbing/perforation limits, under high velocity projectile impact, are mainly concerned by protective engineers, which are numerically studied based on an improved dynamic concrete model in this study. Firstly, based on the framework of the KCC (Karagozian & Case concrete) model, a dynamic concrete model is proposed which considers an independent tensile damage model and a continued transition between dynamic tensile and compressive properties. Secondly, the strength surface, equation of state and damage parameters of the proposed model are comprehensively calibrated by a triaxial compressive test with high confinement pressure, the rationality of which is further verified based on the single element tests, e.g., uniaxial and triaxial compression as well as uniaxial, biaxial and triaxial tension. Thirdly, a series of projectile high velocity impact tests on thin and thick concrete panels are simulated, which indicates that the projectile residual velocity and dynamic fracture failures are reproduced satisfactorily, while the KCC model underestimates both the spalling and scabbing dimensions severely. Finally, based on the validated concrete model and finite element analyses approach, the validations of the existing five empirical formulae are evaluated, in terms of the depth of penetration (DOP) and scabbing/perforation limits of concrete panel. Both the Army corps of engineers (ACE) and modified National Defense Research Committee (NDRC) formulae are recommended in the design of the protective structure to avoid scabbing failure.

Cone cracking in human bone: A CT case review series

• Cone cracking is the mechanism responsible for the production of beveling in bone. • Beveling results from impacts, including projectile or blunt. • Case studies reveal and support the cone cracking mechanism of bevel formation. Skeletal trauma analysis often involves the assessment of the types and patterns of fractures, followed by categorizing the trauma into one of several broad “mechanisms.” Trauma analysis ideally also involves understanding the underlying mechanistic basis for the bone's failure. Beveling in bone is one example of a fracture pattern that is often cited as evidence of a high-velocity projectile impact, but appears to be poorly understood in terms of both the mechanism for bevel production as well as the loading conditions responsible for its formation. It has recently been demonstrated that bone beveling results from a failure mechanism called cone cracking, which is also associated with lower velocity impacts. Many case reviews and instructional texts include imagery of beveled bone in association with projectile impacts, but present various other explanations (or no explanation) for the fracture mechanism responsible. Five cases are presented here involving cone cracking in human forensic cases. For each case, the associated fracture patterns are discussed, photographic and micro-CT imagery are shown, and a review of the cone crack is presented in cross-section. The diagnostic utility of CT examination of ambiguous perforations is also highlighted.

High-velocity projectile impact response of rubber-coated aramid Twaron fabrics

The impact response of aramid Twaron CT709 fabrics thinly coated with a commercially available spray-on rubber material has been studied for the first time. Both neat and rubber-coated fabric targets were subjected to impact using 12 mm, 7.05 g spherical steel projectiles. The impact velocities ranged from 150 to 250 m/s. Each target consisted of three plies of neat or coated fabrics. Residual velocities, impact velocities and transverse deformation profiles were recorded using a high-speed camera, and the mechanism of failure and energy absorption were studied. It was observed that the ballistic limit velocity (BLV) increased by 18% in the rubber-coated specimens compared with neat fabric specimens. A critical velocity (Vc) was established below which the coated targets absorbed higher energy than their neat counterparts. The rubber coating was found to promote a membrane effect with global deformation to failure leading to higher energy absorption than the neat counterparts. However, the coated samples absorbed lower energy for impact velocities greater than Vc. At these velocities, the rubber-coated specimens showed localised failure leading to lower energy absorption than the neat counterparts. A novel numerical modelling approach was proposed to simulate coated fabrics, and the models predicted the BLV with high accuracy (error < 4%).

Impact response of a partially filled fuel tank subjected to high-velocity projectiles

ABSTRACT This study investigates the effects of baffles and various other design changes on a partially filled fuel tank subjected to high-velocity projectile impact. Modelling of the tank filled with water is done using ANSYS software. The Eulerian domain is used to analyse water, whereas the Lagrangian domain is used to assess the tank and bullet. The developed finite element model is verified with available results in the literature. The effect of design parameters like edge fillet, number of baffles, thickness of baffles, orientation of baffles, height of baffles, position of the projectile and projectile speed on the impact responses of the fuel tank is studied. From the analysis results, it could be observed that the edge fillet provided the minimum stress due to the lower stress concentration on the fuel tank, but it was not effective in decreasing the velocity of the projectile. Therefore, the baffles are introduced inside the fuel tanks, which are highly effective in reducing the velocity and generating huge stress on the tanks. The velocity and position of the projectiles are also varied to understand their effect on the fuel tank.

Shock resistance of elastomer-strengthened metallic corrugated core sandwich panels

How polyurea coating affects the shock resistance of fully-clamped metallic corrugated core sandwich panels against high-velocity aluminum foam projectile impact is systematically elucidated via a mixed experimental and numerical investigation. Dynamic deformation process, deformation/failure modes, and permanent deflections of polyurea-coated sandwich panels are testified at various projectile momentum and compared with those of non-coated sandwich panels. A high-fidelity finite element (FE) model considering both rate-dependent compressive and tensile behaviors of polyurea elastomer is established and employed to simulate the dynamic response of polyurea-coated sandwich panels, interrogate the underlying enhancement mechanisms, and estimate the effects of projectile momentum and coating thickness/area/position upon permanent mid-span deflection and energy absorption. Reasonable agreement is realized between FE predictions and measurements. The presence of polyurea coating helps curtail permanent deflection in the central region and avoid shear failure around the clamping area. The benefit of polyurea coating on mitigating impact deformation remains stable as the projectile momentum is varied over a broad range, and the use of thicker, larger, and impact-side coating is preferred. The observed performance improvement is attributed mainly to enhanced plastic bending moment and membrane force in the polyurea-coated sandwich panel. The results of this study open up a new avenue to enhance the shock resistance of metallic sandwich structures subjected to impulsive loading.

Investigation on High Velocity Impact of Projectile on Double Layered Geomaterial

Investigation on High Velocity Impact of Projectile on Double Layered Geomaterial

Response of laminated float glass to 9 mm projectile impact

This paper presents an experimental study on the performance of laminated float glass plates against high-velocity projectile impact. Two configurations of the specimen’s layers were used, 5 layers (3 glass and 2 polymer interlayers) and 7 layers (4 glass and 3 polymer interlayers). The specimens were suspended on steel ropes for stress-free boundary conditions. The projectile was a standard in-service 9 mm Luger fired from a distance of 20 m. The results showed that both layer configurations are more than capable of stopping the projectile. However, only the higher layer count was able to stop the formation of significant damage to the backside of the specimen, from which a certain amount of harmful debris could have been released. The higher layer count also prevented the formation of radial cracks.

Metallic composite material to protect against high-velocity projectiles and high energy impacts

The catastrophic failure of structures due to the impact of high energy waves or high speed projectiles can occur in a wide range of situations, including ballast impacts on high speed trains, manmade terrorist acts or accidental industrial events. High energy absorbing materials are therefore essential for the protection of both the hardware as well as personnel. One common requirement in all applications is the development of materials with reduced weight whilst guaranteeing high energy absorption levels. The aim of this work has been the investigation of lighter weight metallic composite systems with suitable properties aimed primarily at withstanding high-velocity projectiles and high energy impacts. (E&asymp; 100 J or v &asymp; 120 m/s). Metallic hybrid test panels have been designed and manufactured using both aluminum and aluminum foam layers. To evaluate their efficiency in the case of a high energy impact the panels have been tested under simulated high-velocity projectile impact conditions by means of a pneumatic air cannon.. The tested panels have been assessed using visual inspection as well as X-ray tomography and IR thermography. The panel deformation as well as the delamination between structural layers has been assessed for the different proposed solutions.

Effect of directionally distributed steel fiber on static and dynamic properties of 3D printed cementitious composite

The reliability of 3D printed cementitious composite (3DPCC) is a major consideration for scientists. Steel fiber as a common method for reinforcement of cementitious composite was studied in this research for its effect on mechanical and dynamic properties. The distribution of steel fiber in 3DPCC was characterized by stereomicroscope and CT scanning method. Steel fibers were parallel to the print direction and distributed directionally in different degree at horizontal and vertical planes. The mechanical properties of 3DPCC was significantly influenced by directionally distributed steel fibers. Functional graded 3D printed cementitious composite (FGPCC) was prepared for coupled impacts including high velocity projectile impact and explosive impact. The crater depth and failure pattern of coupled impact were significantly changed by directionally distributed steel fibers. Modified empirical models were proposed for 3DPCC according to experimental results.

Resistance of hybrid layered composite panels composed of fiber-reinforced cementitious composites against high-velocity projectile impact

The purpose of this study is to present an experimental investigation of the impact resistance of hybrid layered panels composed of high-strength fiber-reinforced composite and high-ductility fiber-reinforced composite. Seven types of panels were prepared with three types of composites and hybrid use of composites. A series of experiments including static loading tests and high-velocity projectile impact load tests was performed. From the test results, it was found that the hybrid layered panels, in which a high-strength composite was located at the front side and a high-ductility composite was located at the rear side, had impact resistance higher than those of other panels. It was also observed that the hybrid layered panels showed different damage patterns than those of the panels made of single material.