Ballistic Limit Research Articles

Numerical investigation on effect of different projectile nose shapes on ballistic impact of additively manufactured AlSi10Mg alloy

In the last few years, due to the superior mechanical qualities of Additive Manufacturing (AM) AlSi10Mg alloy to those of traditional casting process AlSi10Mg alloys, the application of AM technology has significantly increased. The ballistic impact research has a wide range of uses, notably in the mining, construction, spacecraft and defence sectors. This work focuses on analyzing the behavior of different projectile nose shapes on the AlSi10Mg alloy fabricated by AM. There are several projectile nose forms to consider, including blunt, hemispherical, conical, and ogive shapes. The impact of various projectile shapes on the ballistic limit of the additively created AlSi10Mg alloy is carefully examined in this study. All numerical simulations were carried out using LS-DYNA software, and the Johnson-Cook material and damage model were considered to assess the ballistic resistance behavior. The ballistic limit for various projectile shapes is computed using the Jonas-Lambert model, which describes the connection between residual velocity and starting projectile velocity. The results showed that, the ogive-shaped Projectile offers the highest ballistic limit, and the blunt projectile shows the lowest ballistic limit for a 5 mm thin target plate. The ballistic impact phenomenon showed plugging failure for the blunt nose projectile, the formation of plug and small fragments were observed in the case of hemispherical nose projectile, fragmenting failure is observed with radial necking in the case of conical nose projectile and petals are formed at the impacted zone in ogive nose shape projectile. Moreover, the ballistic limit of AM AlSi10Mg alloy was slightly higher compared to the ballistic limit of the die-cast AlSi10Mg alloy for the 7.62 mm AP bullet (core). Therefore, AM AlSi10Mg alloy may have equal or good ballistic properties compared to die-cast AlSi10Mg alloy.

Penetration mechanics of ceramic/metal functionally graded plates under ballistic impact: An experimental perspective

This paper deals with a comprehensive experimental analysis of the penetration mechanics and failure mechanisms of SiC/AA6061 functionally graded plates under ballistic impact. The external, cross-sectional, and high-speed photographic damage and failure assessments of the plates were performed. The novelty of this study is to investigate the ballistic impact behavior of a ceramic/metal functionally graded plate with different compositional gradients in a wide range of impact velocities considering below and above the ballistic limit and to reveal a detailed analysis of the damage and failure mechanisms of the plate. This can provide fundamental insights into the design of ceramic/metal functionally graded armor materials. The results indicate that the metal-dense gradient plate shows localized ductile failures as ductile perforation and plugging, whereas the ceramic-dense gradient plate exhibits brittle failures as comminution and conoidal fracture. Tailoring a relatively continuous compositional gradient instead of an abrupt variation, namely the linear gradient, provides tensile stress wave attenuation and resistance to crack growth and fracture.

Comprehensive understanding of electron mobility and superior performance in sub-10 nm DG ML tetrahex-GeC2 n-type MOSFETs.

In this study, we have investigated the electron mobility of monolayered (ML) tetrahex-GeC2 by solving the linearized Boltzmann transport equation (BTE) with the normalized full-band relaxation time approximation (RTA) using density functional theory (DFT). Contrary to what the deformation potential theory (DPT) suggested, the ZA acoustic mode was determined to be the most restrictive for electron mobility, not the LA mode. The electron mobility at 300 K is 803 cm2 (V s)-1, exceeding the 400 cm2 (V s)-1 of MoS2 which was calculated using the same method and measured experimentally. The ab initio quantum transport simulations were performed to assess the performance limits of sub-10 nm DG ML tetrahex-GeC2 n-type MOSFETs, including gate lengths (Lg) of 3 nm, 5 nm, 7 nm, and 9 nm, with the underlap (UL) effect considered for the first two. For both high-performance (HP) and low-power (LP) applications, their on-state currents (Ion) can meet the requirements of similar nodes in the ITRS 2013. In particular, the Ion is more remarkable for HP applications than that of the extensively studied MoS2. For LP applications, the Ion values at Lg of 7 and 9 nm surpass those of arsenene, known for having the largest Ion among 2D semiconductors. Subthreshold swings (SSs) as low as 69/53 mV dec-1 at an Lg of 9 nm were observed for HP/LP applications, and 73 mV dec-1 at an Lg of 5 nm for LP applications, indicating the excellent gate control capability. Moreover, the delay time τ and power dissipation (PDP) at Lg values of 3 nm, 5 nm, 7 nm, and 9 nm are all below the upper limits of the ITRS 2013 HP/LP proximity nodes and are comparable to or lower than those of typical 2D semiconductors. The sub-10 nm DG ML tetrahex-GeC2 n-type MOSFETs can be down-scaled to 9 nm and 5 nm for HP and LP applications, respectively, displaying desirable Ion, delay time τ, and PDP in the ballistic limit, making them a potential choice for sub-10 nm transistors.

The ballistic performance of plain-weave multi-ply systems: An experimental investigation

This paper studies the influence of the weave parameter on the ballistic performance of multi-ply systems. Three types of plain weaves were put into investigation, namely, A090, A200, and A400. Tensile and yarn pull-out tests were performed to investigate the responses of fabric upon quasi-static loading. Penetration tests were performed to characterize the energy absorption capability of different multi-ply systems at impacting velocities ranging from 250 m/s to 460 m/s. It was found that the strength of the fabric sample increased almost linearly with fabric areal density, and the coarser weaves exhibited a greater resistance against yarn pull-out. The ballistic limit ( V50) of finer weave 13A9, is around than 42.5% higher than coarser weave 3A4. In terms of hybrid systems, placing finer fabrics in front and coarser fabrics in the rear exhibits higher ballistic limits than the reversed sequence (8–20 m/s differences), while placing coarser fabrics in front exhibited greater energy absorption capability when the impact velocity is sufficient to cause instant and localized failure. It was also found that the ballistic performance of the hybrid systems does not alter significantly with the mass percentage of the coarser weaves at high impact velocities (greater than 400 m/s). The results indicate that replacing the expensive ballistic weaves with cheap materials in a hybrid system is a reasonable alternative to achieve cost reduction without significant performance degradation.

Numerical analysis of an experimental ballistic test of Al/SiC functionally graded materials

Metal/ceramic functionally graded materials (FGMs) have been increasingly used for impact-resistant applications because of their ability to combine the strength of both components. However, understanding the local response of FGMs under ballistic impact conditions remains a complex nonlinear problem. Moreover, performing experimental investigations is difficult due to technical limitations in measuring critical parameters such as stress, strain, and pressure. That is why research in this field also concentrates on modeling methodologies, such as numerical simulations. In this study, a finite element model (FEM) was implemented to investigate the behavior of a particular metal/ceramic-based FGM impacted with fragment-simulating projectiles (FSPs). The studied FGMs, exhibiting an elastoplastic behavior, were composed of aluminum (Al) and silicon carbide (SiC). The ceramic volume fraction (Vc) varies according to a power-law distribution, through the thickness. Their effective material properties were evaluated using a homogeneization-based self-consistent method. FGM’s dynamic behavior was described using the dynamic Tamura-Tomota-Ozawa model (DTTO). The numerical simulations were in good correlation with experimental results. The importance of the DTTO model's introduction and the calibration of the plastic strain criterion in the failure modeling of FGMs were highlighted. In addition, it was observed that the variation in the composition exponent and grading continuity of mechanical properties has a significant effect on the predicted ballistic limit. It was finally noted that a linearly-composed 5-layerbased specimen exhibited a higher level of ballistic resistance.

Ballistic performance of bio-inspired hybrid interleaved composite structures suitable for aerospace applications

We investigate the ballistic performance of an aircraft engine containment casing demonstrator, made of composite materials with a novel bio-inspired hybrid interleaved design, under high-velocity impact (HVI) at a specific angle. Firstly, we apply a bio-inspired (BI) helicoidal design to develop a large-scale monolithic laminate concept made of carbon fibre-reinforced polymer (CFRP). Then, we hybridise the developed BI laminate concept with interleaved blocks of Zylon fibre (PBO)-reinforced polymer to develop a large-scale BI hybrid interleaved laminate concept. We then further hybridise the developed BI hybrid concept with titanium (Ti) foils (located at the impact face) so that in total we have three large-scale laminate concepts. We manufacture 6 large-scale laminates from each concept with dimensions of 225 × 225 mm and a target areal weight of 0.95 g/cm2. We then test them (perpendicularly) under HVI ranging from 150 to 300 m/s to obtain the ballistic limit and energy dissipation. Secondly, after selecting the best-performing developed laminate concept, we scale it up to develop industrial demonstrator panels with a target areal weight of 1.5 g/cm2 and dimensions of 550 × 360 mm. We test the panels under HVI at an angle of 55° with a larger and heavier projectile, to more closely represent a fan blade-off event onto the engine casing. The results of the large-scale laminate concept tests show that the BI hybrid interleaved CFRP/PBO concept outperformed the rest of the concepts with 54% and 34% improvement in energy dissipation compared to that of quasi-isotropic (QI) and the BI monolithic CFRP, respectively. Our results show that small-scale designs for HVI-resistant CFRP-based laminates cannot be simply assumed to exhibit an equivalent performance for industrial applications with thicker laminates, heavier projectiles and impacts at an angle.

Investigation into the ballistic characterization of polyurea-coated spliced-shaped multilayer ceramic plates

As a new protective structure, composite ceramic structures have become a research focus and new breakthrough direction. We using a ballistic gun to fire a 12.7 mm bullet at a speed of 500 m/s to penetrate the polyurea-coated spliced-shaped multilayer ceramic plates. The energy absorption effects of the polyurea and ceramic on fracture were analyzed. The ceramic fracture microstructure was subsequently investigated by scanning electron microscopy (SEM), and the fracture principle was elucidated. The residual velocity of the projectile was predicted from energy dissipation. In addition, the failure process of polyurea/ceramic composite plates was explained in detail using numerical simulations, and the ballistic limit of different configuration composite plates was explored through theoretical and numerical simulation methods. This research showed that polyurea could effectively improve the ballistic limit of composite structures and increase its ballistic limit from 133.9 to 174 m/s, resulting in an increase of ∼30.4 %. However, polyurea had little effect on the ballistic performance of the structure under the condition of equal area density. The energy absorption process of five structures was mainly divided into four stages, and the coating of polyurea could effectively improve the energy absorption of ceramics, reaching 253.84 %.

High‐velocity ballistic response of AA 1100‐H14 based carbon‐fiber metal laminates: An experimental investigation

AbstractA detailed experimental investigation was carried out for the high‐velocity ballistic response of AA 1100‐H14 based carbon‐fiber metal laminates (FMLs). FMLs with different metal volume fractions and the same thickness of carbon‐epoxy fiber laminates were tested to examine the surface and internal damage. The ballistic performance parameters, namely % escalation in absorbed energy, specific energy absorbed, ballistic limit, specific perforation energy, first cracking energy, and global deformation profile, were studied and a comparison was drawn with pure carbons fiber reinforced epoxy composite laminates. Despite having greater thickness, pure carbon fiber‐reinforced epoxy composite laminates absorbed less impact energy than FMLs and failed catastrophically. For FMLs, the % escalation in the absorbed energy and the specific energy absorption kept increasing with the increasing impact velocity until the onset of perforation. Once the perforation started, both these parameters showed a decreasing trend. Thick FMLs absorbed a good amount of energy, leading to projectile recoil suffering minimal damage. The ballistic velocity, specific perforation energy, and first cracking energy on the front and rear face of FMLs layers showed an increasing trend. The minimum for the thinner and maximum for the thicker FMLs attributed to the large thickness and more metal volume fraction. Contrary to the large deformation of the impacting points, pure carbon fiber‐reinforced epoxy composite laminates showed very minimal deformation as compared to FMLs. The brittle nature of the epoxy resin resisted the deformation to a large extent leading to less energy absorption.Highlights High‐velocity ballistic response of AA 1100‐H14 based carbon‐FMLs was investigated. Ballistic performance parameters of FMLs were studied and was compared with carbons fiber reinforced composite laminates. The ballistic limit of FMLs showed a direct dependence its thickness and metal volume fraction. In the absence of any metallic layer, pure carbons fiber reinforced composite laminates absorbed less impact energy.

Eccentric ballistic impact of fiber-metal laminates and aluminum plates supported with different boundary conditions

This article investigates the eccentric ballistic impact response of square aluminum and fiber-metal laminated plates with the ANSYS AUTODYN hydrocode. The plates are impacted by a cylindrical projectile with normal high velocity. The validation of the numerical procedure is mainly carried out through comparisons with published experimental data. The modeling procedure and the verification of numerical results are described in detail so as to provide a useful reference. The effect of impact point eccentricity and different boundary conditions on the ballistic resistance of the targets is evaluated. It is found that the ballistic limits of the considered targets can be substantially affected by the boundary conditions and the eccentricity of impact. The targets are sorted in a descending order of ballistic resistance which is found invariant to the impact position.

Ballistic and delamination mechanism of CFRP /aluminum laminates subjected to high velocity impact

This work focus on the experimental study of ballistic and delamination mechanism on carbon/epoxy laminates with [-45/90/45/0] stacking sequence. A series of impact tests were carried out on the monolithic CFRP and Al/CFRP/Al laminates targets. The two targets were compared in terms of ballistic limit, energy absorption, penetration process, damage mechanism and interfacial delamination. Results showed that the Al/CFRP/Al laminates with equal thickness had better ballistic performance than that of the monolithic CFRP laminates. The delamination of adjacent layers was mainly controlled by bending moment, uneven stress distribution of interface and mismatch of wave impedance between layers with different lay-up directions. The shear wave propagated between fiber layers in different layering directions, resulting in interlayer crack extension.

Local impact resistance of curved sandwich panel with Miura-ori foldcore

Curved sandwich structures have demonstrated great potential for engineering applications. However, little study on the impact resistance of the curved Miura-ori sandwich structure is found. In this study, the curved sandwich panel with a curved Miura-ori foldcore (CPCM) is proposed and its impact resistance is numerically investigated. The force displacement history, energy absorption, specific energy absorption, residual velocity of the projectile and the displacement of the rear face sheet are used to evaluate the performances of the CPCM. Various loading scenarios including different impact velocities and positions, different projectile sizes and geometries are considered. Moreover, the curved sandwich panel with a curved honeycomb core (CPCH) that have similar specifications and the same relative density as the CPCM is simulated as well for comparison. It is found that the CPCM shows excellent impact resistance with a ballistic limit around 61 % higher than that of the CPCH. Its energy absorption capacities and impact resistance are improved under blunt projectile impact. However, when the impact velocity is above the ballistic limit, the energy absorption EA of the CPCM remains at a constant level, irrespective of the impact velocity.

Comparative study of hardfacing applications on structural steel surfaces to improve ballistic properties

The aim of this study was to develop plates resistant to ballistic limits by welding on S355JR steel plate with Fe-Cr-C and austenitic electrodes. A total of four different weld coated materials were prepared for ballistic testing. For these four different coatings, E Z Fe 14 (Fe 14), E Fe 16 (Fe16) hardfacing electrodes and E 18 8 Mn R 3 2 (307) austenitic stainless steel electrode were selected, respectively. The coatings were made in the electric arc welding machine, with two different coatings on the surface for each material. These are Fe 14 – Fe 14, Fe 16 – Fe 16, 307-Fe 14 and 307-Fe 16, as the first layer and the second layer, respectively. In all coatings, the welding current was kept constant at 150 A and the welding voltage was kept constant at 27 V. The microstructure, hardness, and ballistic properties of the hardfacing surfaces were investigated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) to analyze the phases and components. The hardnesses of the hardfacing surfaces were determined by Vickers methods from the weld metal to the base metal. Ballistic tests were conducted according to NIJ Level III standards, firing 7.62 × 51 mm AP bullets from a distance of 10 m to calculate the effects of the bullets on the plates, the kinetic energy of the bullet, and the amount of energy absorbed by the plates. Welding for hard surface coating achieved with the combination of 307 - Fe 14 electrodes provides the highest ballistic limit velocity at 830 m/s, while the lowest limit is observed in the material welded with Fe16-Fe16 electrodes at 747 m/s. Fe-Cr-C electrodes were found to be effective as main or auxiliary components when designing armor plates. This study highlights the potential of hardfacing techniques to improve the ballistic properties of steel surfaces, with implications for the development of protective materials across various industries.

Predicting high‐speed particle impact damage in spacecraft thermal protection systems

All spacecraft use some sort of thermal insulation, or thermal protection system (TPS), in their design. TPS materials vary, ranging from ceramic tiles or phenolic ablators for heatshields to lightweight multi-layer insulation (MLI) blankets. Since TPS is usually placed on the spacecraft's exterior, it is susceptible to impacts by meteoroids and orbital debris. These high-speed impacts can damage the TPS to a point where the protection it offers is below acceptable limits. As such, it is important to be able to characterize expected TPS damage levels stemming from such high-speed impacts. In this paper, we present the results of a study that sought to characterize the high-speed impact damage that would be sustained by two TPS materials that have recently gained attention for possible use in future interplanetary missions. Empirical equations were developed for TPS crater depths, as well as maximum and minimum crater mouth dimensions. In the event of TPS perforations, empirical equations were developed for the maximum and minimum through-hole dimensions. As part of the analyses performed, ballistic limit equations (BLEs) for these TPS configurations were also developed where possible. The validity of the equations developed was assessed by comparing their predictions against test data. In nearly all cases, the empirical equations developed herein were seen to adequately capture the magnitudes of the measured damage parameters.

An experimental study of the penetration resistance of UHMWPE laminates with limited thickness

Ultra-high molecular weight polyethylene (UHMWPE) laminates represent the most weight-efficient industrial fiber-reinforced resin-based composite material for ballistic protection. To comprehensively understand the anti-penetration mechanism and quantify the anti-penetration performance of UHMWPE laminates, theoretical, experimental, and equation-fitting methods are employed to study and test the ballistic response characteristics of UHMWPE laminates. The results reveal that UHMWPE fibers possess a theoretically determined longitudinal wave velocity that exceeds 10 km/s and exhibit an extremely strong stress diffusion capacity. The anti-penetration mechanism and performance of UHMWPE laminates are significantly influenced by the laminate thicknesses, projectile velocities, and temperatures. As the laminate thickness increases, the ballistic limits of UHMWPE laminates increase almost linearly. Large area delamination and back face deformation play a crucial role in the energy dissipation of UHMWPE laminates. With the increase of projectile velocities, there exists an energy limit representing the maximum energy absorption capacity of the UHMWPE laminates that is worthy of reasonable utilization in spacing ballistic-proof armors. Additionally, the ballistic performance of UHMWPE laminates generally decreases with increasing temperatures, and this trend becomes more pronounced after 80 ℃. Based on data-driven analysis, this paper proposes an equation for calculating the ballistic limit of UHMWPE laminates that takes into account the temperatures and projectile shapes, with a prediction error basically within 5 %. The research results can offer valuable guidance for the ballistic-proof design of UHMWPE laminates.

Numerical simulation of behavior of multi-layered metal targets impacted by high-velocity striker

The results of numerical simulation of perforation of monolithic and multi-layered targets are presented. The objects of study were monolithic, two-layer, three-layer and air gap targets made of steel 3. The influence of the placement of an additional layer on impact resistance in high-velocity impact (initial velocity was more than the ballistic limit of all targets) was investigated. The behavior of materials was described using a phenomenological macroscopic model of continuum mechanics. A modified Lagrangian method was used for numerical simulation of the perforation process. Test calculations were performed before numerical research. Good agreement on penetration depth of an ogival striker into a semi-infinite metal target was obtained. Numerical simulation found that impact resistance of the triple-layered target was higher than that of the double-layered target and monolithic targets. Post-perforation analysis showed the targets were completely perforated and the striker’s tip was slightly eroded or blunted. Duration of perforation of all targets and damage to their materials were approximately the same, but permanent deformation of additional layers was greater with a triple-layered target. This finding can be explained by a pinching effect of additional layers acting on the striker and decelerating it.

Synthesis and modification of poly (p‐phenylene terephthalamide) for production of light‐weight hybrid composite armors reinforced with polymer composite nanofiber mats

AbstractPoly (p‐phenylene terephthalamide) (PPTA) polymer was synthesized and then modified to eliminate the processing difficulties arising from its insolubility in organic solvents. The chemical structures of the synthesized PPTA and N‐butyl PPTA (BPPTA) were confirmed by elemental analysis, x‐ray diffraction, Fourier transform infrared (FTIR), and 13C‐NMR spectroscopy studies. As a result of modification, an aramid derivative that is soluble in some common solvents was obtained and added into polyacrylonitrile (PAN) matrix in solution. PAN/BPPTA composite nanofiber mats (CNMs) were fabricated by electrospinning. Mechanical tests showed that tensile strength increased by 119% with 3% BPPTA content. The fabricated CNMs were combined with aramid fabrics to produce laminated hybrid armors and ballistic tests were performed following the NATO Stanag 2920 standard. This is the first report about the integration of CNMs into multilayer armor configurations and resulted in improved ballistic limit velocity (V50) with a relatively very small weight gain and emergence of new energy absorption mechanisms.Highlights Alkylation of the para‐aramid yielded an organo‐soluble aramid derivative. Tensile strength of PAN nanofiber mat increased by 119% with 3% N‐butyl PPTA. Integration of the CNMs resulted in new ballistic impact absorption mechanisms. CNMs contribute to V50 with a very low mass gain due to their high surface area/mass.

Dynamic behaviour of multi-layer composite against single and multiple projectile impact loading

In this work, a novel multi-layer composite structure has been proposed for its application in the design of protective shelters. The proposed work investigates the dynamic behaviour of a multi-layer composite under the action of single and multiple projectile impact loading. The target consists of soil, reinforced concrete, steel plate, high-density polyethylene and boulder-mixed cement mortar. It has been subjected to the projectile impact (single and multiple) of a 2.3 kg ogive-nose hard cylindrical projectile having a 50.80 mm diameter. The mechanical performance in terms of the velocity profile of the projectile, residual velocity, penetration depth, ballistic limit velocity, energy absorption and damage of the target has been quantified through a numerical framework. Further, equations have been formulated to determine the fracture material parameters associated with the Riedel–Hiermaier–Thoma (RHT) model to cater for varying strengths of concrete or similar materials. The proposed composite target has demonstrated enhanced penetration resistance and lesser damage compared to its reinforced concrete monolayer counterpart. The interaction between shock waves and the target’s material characteristics lead to projectile ricocheting in multiple projectile impacts. Further, an analytical model has been developed to predict the forces transmitted to the lowest layer, which are essential for design purposes. The model has been proposed from the fundamentals using the concepts of impedance. The result derived from the theoretical formulation is in good agreement with the numerical results. Finally, the damage has been quantified to assess the extent of structural deterioration in multi-layer targets, emphasizing the relationship between energy absorption ratio and damage.

High‐velocity impact behavior and quasi‐static indentation of new elastomeric nanocomposites reinforced with cellulose nanofibers and lignin powder

AbstractThe present study investigates the indentation resistance of elastomeric nanocomposites based on natural rubber with different amounts of cellulose nanofibers (CNFs) under quasi‐static indentation (QSI) and high‐velocity impact (HVI) tests. At first, the baking characteristics and hardness of the samples were checked. The results showed that with the increase in CNFs content, the hardness of the samples increases, and the optimal baking time decreases. A high‐quality final product is produced through good dispersion and acceptable physical bonding between the CNF filler and the rubber chain. Further, the results of quasi‐static indentation showed that the amount of energy absorption for optimal loading of 6 phr increased by 43% compared to a control sample (0 phr). Similarly, from the high‐speed impact results for optimal loading (6 phr), the ballistic limit and energy absorption values increased by 23.6 and 52.7%, respectively, compared to the control sample (0 phr). It was also observed for higher values (9,12 phr) that the glass transition temperature, Tg, effect significantly affected the fracture behavior of the samples due to the high‐speed impact. Finally, CNFs provide better bonding with polymer chains to improve properties through good interaction with natural rubber, making them suitable for energy absorption applications.Highlights New elastomeric nanocomposites reinforced with cellulose nanofibers were made. Increasing the amount of CNFs decreases the optimum curing temperature. The hardness of elastomeric nanocomposites is increased by cellulose nanofibers. The indentation properties of nanocomposites have increased significantly. The optimum value of 6‐phr increased the impact resistance of nanocomposites.

Design and Development of Novel AA7075-T6 based Armor Plate through Numerical and Experimental Approach

The materials used for ballistic applications have always taken a special spot in the manufacturing and study of protective amours. Although metals like steel provide adequate ballistic protection, they compromise the mobility of the soldier and since high mobility is a primary requirement for soldiers during combat. Therefore, at present most of the researchers are currently focusing on materials with properties like high impact resistance and high strength to weight ratio. In recent times, Aluminum alloys are recognized as the alternative materials which can provide good impact resistance and have a high strength to weight ratio and having better corrosion resistant properties which ultimately make it a suitable material for several military applications. In this research, one of the toughest aluminum alloys AA7075-T6 is considered for designing an armor plate and studied for its ballistic resistance. Initially, the monolithic AA7075-T6 alloy of 18 mm was tested for its ballistic resistance limit and further it is designed with the ceramic plate of 3 mm and base alloy AA7075-T6 of 15 mm was tested to evaluate. Later the monolithic alloy of 18 mm was surface reinforced up to a thickness of 3 mm with different types of reinforcements and evaluated the bullet residual velocity after penetration of the armor piercing projectile. Numerical simulation was conducted using the prominent non-linear dynamic analysis software i.e., Ansys AUTODYNE version 19.2 and the respective values for the surface reinforced metal matrix composites revealed excellent results for the depth of penetration and residual velocity of the projectile.

A data-driven approach for predicting the ballistic resistance of elastoplastic materials

Data-driven methods and machine learning methods provide efficient and accurate approaches for solving impact problems. In this paper, a data-driven approach is proposed for numerical simulations of ballistic impact behavior for elastoplastic materials. An enhanced rate-dependent scheme is employed for improving the predictability of the data-driven constitutive model. A new method that introduces a stress triaxiality indicator to three separate constitutive models is proposed to consider the discrepancy between the mechanical responses of materials under tension, compression, and shear. Additionally, a modified Bai-Wierzbicki fracture criterion considering the strain rate effect and the stress-state effect is used to evaluate the fracture behavior of the materials during impact simulations. Subsequently, a compatible numerical implementation algorithm that considers loading, unloading, and reverse loading is established to enable the application of the data-driven approach in finite element simulations. Numerical validation of the proposed data-driven approach is conducted through several simple loading examples, such as cyclic loading, torsional loading, and tension–torsion combined loading. The data-driven approach is then employed to simulate the ballistic impact behavior of Ti-6Al-4V targets of different thicknesses that are struck by blunt projectiles. Impact properties—including the relationship between residual velocity and impact velocity, ballistic limit velocities, and fracture paths—are comprehensively studied. The results demonstrate the reasonable predictability and accuracy of the data-driven approach when applied to ballistic impact simulations.