Projectile Deformation Research Articles

Ballistic Impact Study of an Aramid Fabric by Changing the Projectile Trajectory

Personal protective systems widely use aramid textile fabrics, whether in soft or rigid form, to protect against various types of ballistic threats. Ballistic impact refers to a high-velocity impact caused by a thrusting source, often involving a low-mass object. To use these materials effectively in structural applications, it is crucial to have a thorough understanding of their ballistic behavior when subjected to high-velocity impact. Upon contact of the projectile with the ballistic material, complex ballistic penetration processes take place, which require a comprehensive and quantitative examination for a better understanding. This study aims to analyze the damage mechanism of aramid fabric by altering the projectile impact trajectory based on numerical simulations. We aim to obtain a thorough understanding of the behavior of the aramid fabric by performing numerical simulations and examining the penetration process in detail. The obtained results are analyzed based on the von Mises stress distribution (panel and projectile, projectile only, and main wires), projectile deformation, projectile velocity during ballistic impact, and based on photographs obtained during the impact.

Critical ricochet angle of projectile penetrating into concrete

Abstract The ricochet is an objective phenomenon when a projectile penetrates concrete at an oblique angle. The minimum incident angle at which this phenomenon happens is termed the critical ricochet angle. To enhance the consistency between numerical simulations and experimental studies of the critical ricochet angle, this research has established a numerical model of a deformable projectile penetrating a concrete target. The numerical model has been optimized by considering computational accuracy, efficiency, and practical engineering applications. Through dimensional analysis of factors influencing the critical ricochet angle, the working conditions have been designed with single variables such as impact velocity, target strength, warhead curvature radius, and projectile length. The critical ricochet angle corresponding to each working condition has been calculated by using the optimization model. The results show that the optimized model can simulate the oblique penetration of a projectile into a semi-infinite concrete structure while maintaining calculation accuracy and efficiency. The critical ricochet angle shows a positive correlation with the impact velocity, warhead curvature radius, and projectile length, and a negative correlation with the target strength. Additionally, the projectile deformation is also significant factors affecting the critical ricochet angle. The numerical model developed here is of considerable importance for advancing the methods of critical ricochet angle computation and guiding the design of concrete protection engineering.

Ballistic performance of alumina/carbon fiber/aramid composite against impact of different projectile shapes

This study explores the ballistic performance of an alumina/carbon fibre/KevlarⓇ aramid composite panel against impacts from various projectile shapes, including ogive, conical, cylindrical, hemispherical, and 5.56 mm × 45 mm NATO rounds. The aim is to analyse the influence of projectile nose shape on penetration resistance and energy absorption, critical for defence and aerospace applications. Numerical simulations carried out in LS-DYNAⓇ, validated by experimental data, reveal that the ceramic layer effectively initiates projectile deceleration, while the fabric layers absorb the majority of the kinetic energy. Hemispherical projectiles exhibit minimal plastic deformation, highlighting the composite's optimal performance against this shape. In contrast, ogive projectiles demonstrate greater penetrative potential, challenging the composite's multi-layered defence. The study finds that approximately 90% of the kinetic energy is absorbed by the fabric backing, with a small portion absorbed through projectile deformation and ceramic cracking. These results underscore the importance of considering projectile deformation in simulations and suggest that the composite design is well-suited for enhancing protection against high-velocity impacts in defence and aerospace sectors.

Peridynamics modelling of projectile penetration into concrete targets

A non-ordinary state-based peridynamics (NOSB-PD) model is proposed to simulate the projectile penetration into concrete targets. In this model, the Kong-Fang concrete material model recently proposed is firstly implemented into the NOSB-PD framework to describe the complex dynamic behavior and failures in concrete material subjected to penetration loading, and then an improved point-to-volume discrete frictional contact model is proposed to simulate the physical interaction between projectile and target. After the mesh-free discretization and explicit time integration, the proposed NOSB-PD model is used to numerically predict two sets of projectile penetration experiments into low-strength and high-strength concrete targets. And numerical predictions are found to be in good agreements with corresponding test data including penetration depth, projectile deceleration, deformation of projectile and failures in concrete targets.

Numerical model for penetration process of a deformable projectile into ductile metallic target plate considering the interaction of projectile and target

The interaction of projectile and target in a penetration process is key for precise prediction and safety design. However, this interaction is instantaneous and varying with complex physical phenomena, that induces a challenge of panoramically illustrating the penetration process. This work develops a new numerical model that can capture the penetration process of a deformable projectile impacting ductile target plate and meanwhile the interaction of projectile and target is considered. Here, physical mechanisms are explored and accordingly mathematical derivations for theoretical analysis are carried out. The issues of plastic stress wave, contact stress, shear perforation and energy dissipation are involved. Both the deformation of projectile and failure of target plate are addressed which include the upsetting deformation of projectile, pit-opening performance of target plate and perforation of target plate. This model presents the history of the deformation of projectile and target, velocity evolution, penetration resistance and shear perforation with timing. The modelling results show a high-precision prediction by comparing with experimental data of a flat-ended projectile penetrating Weldox 460E steel target plate [54] and other developed models of plugging failure model [13] and plastic wave model [48] for both cases of 16mm- and 20 mm-thickness target plates. This work offers the comprehensive calculation and analysis of penetration process and reveals the insights of the transient phenomena for impact engineering.

High-speed perforation of IN718 plates by spherical TC4 Ti alloy projectiles: Experiments and modeling

Data and knowledge on ballistic performance of Inconel-718 (IN718) alloy is critical for evaluating the resistance of turbine blades against foreign object impacts in aeronautical and astronautical industries. Ballistic perforation experiments (impact velocity 480 ms−1 to 1340 ms−1) with TC4 spherical projectiles (5-mm-diameter) are conducted on IN718 target plates (2-mm-thick) in this work, along with high-speed photography. The IN718 plates show multiple deformation and failure modes (bulging, dishing, petaling and plugging). The ballistic limit velocity for the investigated projectile/target combination is 823 ms−1. Postmortem material characterizations (optical photography, scanned electron microscopy and energy dispersive spectrometry) are conducted on recovered projectiles and bullet hole inner walls, and the observations indicate adiabatic shearing, surface melting and abrasion of projectile material. A finite element model based on the Johnson–Cook constitutive model and failure criterion is established, and reproduces the ballistic experiments. Dimensionless analyses are conducted on the dimensions of postmortem projectiles and bullet holes, and the projectile residual velocity/mass. On the basis of experimental observations and theoretical analysis of the projectile dynamics, the whole perforation process is divided into three stages (the entering, cratering and plugging stages). A multi-stage analytical model on perforation is then developed considering the effects of cavity expansion, projectile deformation and abrasion, and can well predict the projectile dynamics during entering and cratering stages.

High-speed projectile perforation of nickel-based Inconel 718 superalloy plates: Experiments and modeling

Understanding ballistic behavior of structural materials is important for their applications in aeronautical and astronautical industries. We investigate perforation of 2-mm thick Inconel 718 superalloy plates by spherical stainless steel 304 projectiles with high-speed photography at impact velocities ranging from 548 ms−1 to 1360 ms−1. Postmortem target samples are characterized with optical metallography, scanning electron microscopy and electron backscatter diffraction as regards bullet hole morphology and deformation. Grain refinement and shear banding are the main microstructural deformation modes near the bullet holes. Shear dominated deformation and tension–shear dominated deformation of target material occur sequentially in bullet hole along the impact direction. The morphologies of bullet holes and postmortem projectiles are obtained from the experiments and simulations. The effect of projectile deformation on ballistic behavior of the target is investigated. On the basis of dimensional analysis, a quadratic relation is derived between the energy absorption ratio of target and the dimensionless postmortem projectile diameter, along with a phenomenological model that can well predict projectile residual velocities.

Effect of projectile’s nose shape on ballistic performance of ceramic/composite armour: A numerical study

In the present study, finite element analysis were carried out to investigate the ballistic performance of Al2O3-Kevlar 29/epoxy armour system impacted by a 4340 steel projectile. The perforation capacity of a 10 mm thick target was studied against a blunt, ogive, and conical shaped projectile with a fixed diameter and mass of 7.56 mm and 10.7 gm, respectively. The simulations were carried out in Ansys/Autodyn by considering the projectile as a deformable body. The variation of the ballistic limit velocity (BLV) and energy, progressive damage of the target, and projectile deformation were studied comprehensively. It was found that the nose configuration of the projectile significantly influence the target’s ballistic performance. The perforation capacity of the blunt projectile was lower than the ogive and conical shape in all the velocity regimes. At higher impact velocity ( Vi >600 m/s), the target’s resistance was better against the ogive projectile than that of the sharp conical projectile. Interestingly, this phenomenon got reversed when the incident velocity nears the ballistic limit. Also, from the simulation results, it has been possible to obtain the optimum thicknesses of the components for a given total thickness of the armour.

Effects of Engine on Penetration Performance of Semi-Armor Piercing Warhead

In the structural layout of missiles and rockets, the engine is generally placed behind the warhead. In order to investigate the effects of the engine on the penetration performance of semi-armor piercing (SAP) warheads, this study numerically simulated the oblique penetration of an SAP warhead and a free-flight rocket into armor plates. The results showed that under the condition of oblique penetration, the compressive force the warhead underwent was asymmetric and that attitude changes made the body of the warhead easily compressed by the target plate. In addition, the constraint of the engine was found to suppress warhead deflection and reduce projectile deformation.

Deformable nose design for the non-penetrating projectile

This paper deals with the design of a deformable nose for the non-penetrating projectile in order to prevent its body deformation. Numerical, analytical and experimental studies have been carried out to analyze the effect of different nose shapes on the projectile deformation when it hits the brick wall. The projectile consists of an aluminum nose, a thin-walled steel cylinder body, and an end connector. This non-penetrating projectile can be used to carry a cargo that must reach its destination safely, for example in firefighting applications. To pursue this goal, the criterion utilized for the best design in this paper is stress and strain analysis. The geometric shape of the noses includes three types: type (a), type (b), and type (c). The first type of nose was flat shape. This nose was detached from the projectile by impact and did not prevent the projectile deformation. The second type of nose was a combination of flat and conical shapes. The projectile was also deformed by this nose. The third type of nose was a combination of flat, conical, and spherical shapes. Due to the maximum absorption of the impact energy, this type of nose prevented the deformation of the cargo and projectile.

Plastic Deformation of High Explosive Projectile 155 mm during Gun Launch Conditions using Finite Element Method

The structural integrity of artillery projectile 155mm high explosive Extended Range Full Bore (ERFB)boat tail designed for 155mm howitzer guns of 39, 45 and 52 calibre plays a key role inside the gun barrel. Thisprojectile comprises a shell body, a driving band, a boat tail, nubs, an explosive, and a fuze. Plastic deformationof the projectile and stripping of driving band are not permitted, when projectile is fired. An investigational study is necessitated to check the plastic deformation of the projectile subjected to maximum propellant charge pressure.The aim of this study is to check the effective plastic deformation and affirm the structural integrity. A 3-D explicit dynamic structural analysis of 155 mm HE ERFB BT during gun launch conditions is carried out by finite element method using FE code ABAQUS/Explicit. To understand the non-linear mechanical behavior of the projectile, the true stress-strain curves of the materials are considered. The plastic behavior of the projectile subjected to the time-dependent loading is studied by using the von Mises plasticity model. The results reveal that the shell body and boat tail have no plastic deformation and the most stressed component is the driving band. The investigation has affirmed the structural integrity of the projectile during gun launch conditions.

High-speed penetration of cast Mg-6Gd-3Y-0.5Zr alloy: Experiments and modeling

Ballistic impact experiments are conducted on a cast Mg-6Gd-3Y-0.5Zr alloy using spherical projectiles under a wide range of impact velocities. Penetration processes are captured by high-speed camera. Postmortem target samples are characterized via three-dimensional laser scanning, metallographic microscopy, scanning electron microscopy and electron backscatter diffraction. Shear bands and twinning dominate the deformation of Mg-6Gd-3Y-0.5Zr near the crater, and texture changes due to compression caused by cavity expansion. For instance, a finite element model based on Johnson–Cook constitutive model and Mie–Grüneisen equation of state is established. Four dimensionless quantities related to craters and projectiles are defined. An analytical model based on dynamic cylindrical cavity expansion model is applied considering projectile deformation, and consistent well with experimental and simulated results over the entire incident velocity range.

Macro-phenomenological high-strain-rate elastic fracture model for ice-impact simulations

The ice impact can cause a severe damage to an aircraft’s exposed structure, thus, requiring its prevention. The numerical simulation represents an effective method to overcome this challenge. The establishment of the ice material model is critical. However, ice is not a common structural material and exhibits an extremely complex material behavior. The material models of ice reported so far are not able to accurately simulate the ice behavior at high strain rates. This study proposes a novel high-precision macro-phenomenological elastic fracture model based on the brittle behavior of ice at high strain rates. The developed model has been compared with five reported models by using the smoothed particle hydrodynamics method so as to simulate the ice-impact process with respect to the impact speeds and ice shapes. The important metrics and phenomena (impact force history, deformation and fragmentation of the ice projectile and deflection of the target) were compared with the experimental data reported in the literature. The findings obtained from the developed model are observed to be most consistent with the experimental data, which demonstrates that the model represents the basic physics and phenomena governing the ice impact at high strain rates. The developed model includes a relatively fewer number of material parameters. Further, the used parameters have a clear physical meaning and can be directly obtained through experiments. Moreover, no adjustment of any material parameter is needed, and the consumption duration is also acceptable. These advantages indicate that the developed model is suitable for simulating the ice-impact process and can be applied for the anti-ice impact design in aviation.

Role of Nuclear Driving Potential to Probe Quasi-Fission Phenomena

The role of entrance channel parameters, namely the target and projectile deformation, coulomb factor, and the mass asymmetry on the nuclear driving potential, are investigated. Distinct signature of mass drift is observed on the potential landscape across the studied reactions and within the reactions forming the same compound nucleus. The influence of nuclear shells is also reported. No significant structures on the potential energy surface are observed for multi-modal nature of fission. Thus, the driving potential can be employed as a useful probe to study quasi-fission or multi-modal nature of fission.

Damage characteristics of semi-infinite aluminium targets subjected to normal and oblique projectile impact

The present study investigates the ballistic performance of 50 mm thick 7075-T651 aluminum target against 7.62 API projectile. The focus of this study is to understand the dissipation of total energy engendered by the projectile in impacting the plate target at 0 (normal), 30° and 60° obliquities. Further, the penetration mechanisms and local as well as global plastic deformations developed in the target and projectile were explored. The ballistic experiments on the targets were performed by employing a universal gun and the depth of penetration of the projectile in the target was observed. Three-dimensional computational modelling of projectile and target was carried out in ABAQUS/Explicit module. The material response of both projectile and target was described by the Johnson-Cook strength and damage model. The influence of projectile deformation on the impact resistance of targets was also studied. The plastic strain energy dissipation in the target as well as projectile was evaluated using the validated numerical results and discussed in terms of the damage evolution and local as well as global deformation modes developed in the target and projectile during the impact process.

NUMERICAL AND EXPERIMENTAL STUDY OF CERAMIC/STEEL COMPOSITE FOR STRUCTURAL APPLICATIONS

The Terminal ballistics is the study of science that deals with the interaction involved in two impacting bodies. This research focused on the high-impact resistance of layered composite comprising of alumina ceramic and armour steel. The composite was designed to have ceramic as the facial plate with armour steel as its backing plate. For the numerical study, the ceramic thickness was varied (6, 8, 10, 12 mm) while keeping the thickness of backing steel constant (7 mm). The projectile, 7.62 mm armour-piercing (AP), was set with a velocity of 838 m/s and made to impact the different ceramic–steel composite target configurations at zero obliquity. The study captured fracture processes of the ceramic, the deformation of projectile, and backing steel. An effective optimum thickness ratio of 1.4 (ceramic:steel; 10/7) for the ceramic/steel components with less deformation of the backing steel is found. Thereafter, the result of the numerical study was validated by experimental ballistic investigation of the determined optimum ceramic/steel ratio. The experiment corroborated the simulation results as the alumina ceramic provided efficient protection to armour steel component after a severe interaction with the impacting projectile.

Analytical investigation on deformation of PELE projectile and opening damage to concrete target

A penetrator with enhanced lateral effects (PELE), which is a particular thin-walled structure, is characterized by a low-density filling material surrounded by a high-density jacket material. When the PELE projectile penetrates a concrete target, the target is destroyed by its thin-walled jacket to a large opening. An analytical model describing deformation mode of the jacket during the penetration process is presented. Due to opening diameter of target plate is larger than projectile diameter under condition of a thin concrete target, a relationship between opening diameter of target plate and projectile diameter, based on existing experimental results of ridge projectile penetrating thin concrete target, is formulated. The relationship combined with the analytical model is used to predict opening diameter of concrete target. A quantitative comparison between the jacket deformation mode obtained from analytical results and experimental results is made to validate the accuracy of the analytical model proposed. As a result, the analytical results exhibit good correlation with experimental observations in terms of the opening diameter of target plate and the deformation mode of projectile jacket. In addition, the influence mechanism of three factors (jacket strength, impact velocity, and target thickness) on the opening diameter is analyzed. The jacket strength affects the opening diameter by changing the plastic limit bending moment of the jacket. Even though the impact velocity affects the opening diameter by changing the interaction force between the jacket and the target, it is equivalent to indirectly changing the jacket strength. However, the target thickness affects the opening diameter by changing the penetration time.

Development of Laser-induced Projectile Impact method and plastic deformation behavior at high strain rate

Development of Laser-induced Projectile Impact method and plastic deformation behavior at high strain rate

Imaging Appearance of Ballistic Wounds Predicts Bullet Composition: Implications for MRI Safety.

OBJECTIVE. The purpose of this article was to determine whether the radiographic and CT appearance of ballistic projectiles predicts their composition and to characterize the translational, rotational, and temperature effects of a 1.5-T MRI magnetic field on representative bullets. MATERIALS AND METHODS. Commercially available handgun and shotgun ammunition representing projectiles commonly encountered in a clinical setting was fired into ballistic gelatin as a surrogate for human tissue, and radiographs and CT images of these gelatin blocks were obtained. MR images of unfired bullets suspended in gelatin blocks were also obtained using T1- and T2-weighted sequences. Magnetic attractive force, rotational torque, and heating effects of unfired bullets were assessed at 1.5 T. RESULTS. Fired bullets were separated into ferromagnetic and nonferromagnetic groups based on the presence of a debris trail and deformation of the primary projectile in the gelatin blocks. Whereas ferromagnetic bullets showed mild torque forces and marked imaging artifacts at 1.5 T, nonferromagnetic bullets did not have these effects. Heating above the Food and Drug Administration limit of 2°C was not observed in any of the projectiles tested. CONCLUSION. Patients with ballistic embedded fragments are frequently denied MRI because the bullet composition cannot be determined without shell casings. We found that radiography and CT can be used to identify nonferromagnetic projectiles that are safe for MRI. We also present an algorithm for determining the triage of patients with retained bullets.

Role of neutron transfer in sub-barrier fusion

Fusion excitation function of $^{35}$Cl + $^{130}$Te system is measured in the energy range around the Coulomb barrier and analyzed in the framework of the coupled-channels approach. The role of projectile deformation, nuclear structure, and the couplings of inelastic excitations and positive Q$-$value neutron transfer channels in sub-barrier fusion are investigated through the comparison of reduced fusion excitation functions of $^{35,37}$Cl +$^{130}$Te systems. The reduced fusion excitation function of $^{35}$Cl + $^{130}$Te system shows substantial enhancement over $^{37}$Cl + $^{130}$Te system in sub-barrier energy region which is attributed to the presence of positive Q-value neutron transfer channels in $^{35}$Cl + $^{130}$Te system. Findings of this work strongly suggest the importance of +2$n$ - transfer coupling in sub-barrier fusion apart from the simple inclusion of inelastic excitations of interacting partners, and are in stark contrast with the results presented by Kohley \textit{et al.}, [Phys. Rev. Lett. 107, 202701 (2011)].