Ballistic Velocity Research Articles

An experimental and numerical investigation of ballistic penetration behaviors of deployable composite shells

Bistable composite shells are suitable candidates for deployable space structures due to high stiffness to weight ratio as well as large volume reduction. Nevertheless, impact performance of bistable composite shells conflicting with space debris have been rarely studied. In this paper deployable hybrid composites constructed with combinations of carbon–carbon, carbon–kevlar, kevlar–kevlar, high-energy-absorption graphene-reinforced polyurethane elastomers are developed, and their ballistic penetration behaviors are experimentally and computationally studied. The influences of ballistic velocity on the absorbed energy, the residual velocity and damage morphology of the targets are investigated in both deployed and coiled stable states. The results show that severe local damages were observed for the carbon–carbon and carbon–kevlar samples after penetration with various velocities even first cosmic velocity, and the sample of deployable hybrid composite shell yielded the best ballistic impact resistance. The total energy absorption performance of the hybrid composite structure was greatly improved by introducing graphene-reinforced polyurethane elastomers without losing the deployability. Additionally, investigation on the energy absorption capability of deployed laminated shells with various curvature radii indicated that the curvature radius had a significant effect on the anti-penetration performance.

A self-sensing Al/aramid hybrid laminate for detection of MMOD collision with electrical resistance tomography

Aiming at the micrometeoroid/orbital debris (MMOD) collision problem for space structures, this paper proposes a self-sensing aluminum/aramid hybrid laminate for detection of MMOD collision event and identification of its associated damage. A co-curing method is used to fabricate the hybrid laminate while carbon nanotube (CNT) film and flexible printed circuit (FPC) are embedded in the laminate as sensing layer. By injecting tiny currents into the CNT film before and after MMOD collision and collecting the corresponding boundary voltages, electrical resistance tomography (ERT) is employed to reconstruct tomographic image of the conductivity change caused by MMOD collision and provide information about the damage. Experimental studies have conducted to perform ballistic high velocity impacts to simulate MMOD collision to three self-sensing hybrid laminates. The results have demonstrated that, the CNT film has good sensing performance, and the reconstructed image of conductivity changes can reflect the location and approximate size of the damage, validating the effectiveness of the proposed self-sensing hybrid laminate and providing a new way for space structures to detect MMOD collisions.

Research on ballistic performance of green shear thickening functionalized fabric based on solid waste modification

Based on the solid waste-based modification, green shear-thickening functionalized ballistic composites were prepared. Silica aerosols were obtained from solid waste diatomaceous earth through sol–gel preparation, gel aging, and supercritical drying. The modified silica aerosols acted as the dispersed phase, regulating the green shear-thickening liquid. A comparison was made between the performance of the modified shear-thickening liquid (SG@STF) and traditional shear-thickening liquids. By modifying solid waste based shear thickener (SG@STF) Combined with aramid fabric (AF) to test Ballistic performance. Characterization tests revealed that the rheological properties of SG@STF were significantly enhanced by increasing the volume fraction of the dispersed phase in STF from 50 % to 60 %. This enhancement was attributed to the addition of reactive functional groups on the surface of the silica sol. Yarn pull-out tests demonstrated that SG@STF/AF improved the tensile strength by 120 % compared to AF fabric, thanks to its superior friction properties. Ballistic tests showed that SG@STF increased the ballistic ultimate velocity of AF fabric by 105 %, elevating AF’s ballistic limiting velocity from 51 m/s to 105 m/s. Consequently, SG@STF/AF exhibited superior ballistic properties compared to AF fabric. The doping of SG enhanced the friction between yarns and increased the load-bearing area of the fabrics, thereby improving the ballistic properties of SG@STF/AF and achieving the desired modulation of their ballistic properties.

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.

Development and ballistic impact study on environment friendly sustainable jute reinforced carbon black/lignin-based elastomeric flexible composites

This study compares the behaviour of jute/elastomer bio-composites based on lignin and carbon black under high-velocity impact using experimental methods. Compared to carbon black, SEM data showed that lignin was more evenly distributed across the yarns. The space between the threads was filled by the good interaction of lignin and rubber. Additionally, the findings of the tensile and dynamic compression tests demonstrate that adding lignin to a matrix enhances the tensile strength of rubber samples and composites. On single-layer and three-layer composites made of lignin and carbon black, experimental tests were conducted utilizing a gas gun apparatus with a flat projectile travelling between 100 and 180 m/s. The damage behaviour of the proposed composites is analyzed. The findings demonstrate that the composites' energy absorption and ballistic velocity have enhanced due to the jute-woven fabric cover and the diluted rubber matrix. The results reveal that single and three-layer lignin-based composites exhibit better ballistic limits with an increase of 12.5% and 23.8% over composites based on single and three-layer carbon black composites. Lignin-based composites outperform carbon black composites in terms of energy absorption with single and three-layered lignin-based composites absorbing 23.5% and 25.86% more energy compared to single and three-layered carbon black-based composites. Additionally, the analysis of energy absorption at the ballistic limit for single-layer and three-layer lignin-based composites reveals an increase of 26.56% and 53.35%, respectively, compared to carbon black-based composites.

Modulation of ballistic injection velocity in phosphorene nanodevices by bias and confinement effects

Atomistic quantum transport simulations are employed to study the electron injection velocity (vinj) and ballistic performance of phosphorene nanoribbon (PNR) field-effect transistors (FETs). We show that PNR bandstructure is immune to quantum confinement effects, which is seen in a rather constant vinj≈2.1 × 107cm/s down to the PNR width of 1.5 nm. Moreover, we demonstrate that the modulation of vinj by gate bias is available only for PNRs wider than 2.1 nm, with the maximum enhancement being 33%. Finally, it is reported that PNR FETs combine high cut-off frequencies above 526 GHz with acceptable bandgap that ranges from 0.7 eV to 1.6 eV in the examined PNR width range, which proves the plausibility of PNRs as channel material for future ultra-scaled high-speed FETs.

A rapid outliers detection and correction method for external ballistic velocity measurement data

Due to the influence of various sudden and abnormal factors during the tracking environment, equipment working conditions, and operation process, there are inevitable outliers in the tracking measurement process of aircraft such as carrier rockets, artificial satellites, and missiles. Therefore, the prerequisite for ensuring the reliability of processing results is to timely and accurately detect and correct outliers. In this paper, we proposed the sliding window-based variable degree B-spline function method (SWVD B-spline), which can handle isolated outliers and spotted outliers. SWVD B-spline uses variable degree B-spline function to model observed data in sliding windows, which can detect and correct outliers point by point along with window sliding. Then, we propose an initial window data selection method to remove outliers in initial windows to ensure the processing effect. In addition, because there are often inflection points in external ballistic velocity measurement data, differential evolution is used to optimize variable degree B-spline in windows that include inflection points to improve processing accuracy. The experimental results verify that SWVD B-spline can handle various outliers rapidly and efficiently.

Strain gauge-based method to determine in-cylinder projectile velocity and gas pressure

Knowledge of internal ballistic pressure and projectile velocity is required to ensure gun safety, reliability, calculation of its range, and evaluation of ammunition. However, existing methods for determining the same are either overly complex, costly or have limitations in their applicability. In this work, the authors address this need by proposing a reliable, simple, cheap, and non-destructive method for determining in-bore pressure, projectile velocity, and acceleration profile using strain measurements. Data from strain gauges were used to detect the projectile’s arrival time at different locations in the barrel and computed projectile velocity and acceleration as a function of projectile position. Finally, acceleration data was used to calculate the pressure behind the projectile. Results were verified using alternative experimental and simulation techniques on two different barrels with different ammunition. It was found that the proposed method works well and thus can be reliably used in similar applications elsewhere.

Ballistic Performance of Thermally Exposed CFRP Composites

In this investigation, high velocity impact test was carried out to study the after effect of thermal loading on ballistic limits of composite laminates. Plain woven carbon/epoxy laminates with nominal thickness of 2.3 mm were fabricated by compression moulding technique. To study the effect of thermal loading, laminates were exposed to different temperatures of 60°C, 80°C, 100°C, 120°C, 140°C and 160°C for 24 h in hot air oven and brought back to room temperature. Impact test was carried out using single stage gas gun for velocity up to 115 m/s. The bullet used was Æ 9.6 mm and mass 14.20 gm. The results show that ballistic limit reduces from 83 m/s to 62 m/s with increase in loading temperature from 30°C to 160°C. For impact velocity above ballistic limit, energy absorbed by the laminates reduces with increase in loading temperature. Shear plug formation was observed during experiment as reported in literatures [4, 5 and 6]. An energy base mathematical model is employed to predict the ballistic limit. The model considered the energy loss due to various failure mechanisms that occurred during impact test. The predicted ballistic velocity and energy absorbed by laminates show good agreement with the experimental results.

Ballistic performance of optimised light weight composite armour

This research paper presents a comprehensive investigation into the response of a 3D finite element model when subjected to 7.62 AP projectiles. The study utilises Hetherington's armour composite equation and incorporates the Johnson-Holmquist material model to analyse the strength and failure criteria of the ceramic and Kevlar/epoxy components, respectively. The results highlight the remarkable resilience of the composite armour, demonstrating its ability to withstand projectile velocities up to 1500 m/s. However, as the ballistic velocity limit increases, the armour experiences significant damage, including projectile erosion and panel delamination. Through numerical simulations and advanced modelling techniques, the paper thoroughly explores the failure modes and energy absorption characteristics of composite armour systems under projectile impact. It investigates key parameters such as velocity, acceleration, kinetic energy, internal energy, pressure distribution, displacement, and damage progression. The analysis reveals a progressive decrease in kinetic energy as the projectile interacts with the armour, underscoring the crucial role of energy absorption in preventing projectile penetration. Moreover, the impact velocity influences the distribution of internal energy within the composite armour, with higher velocities leading to greater energy absorption up to a threshold limit. The study also determines the ballistic limit velocity (V50) using the velocity history approach and validates the findings with existing literature. Overall, the research provides valuable insights into the limitations of composite armour and offers important recommendations for designing and improving materials to achieve superior ballistic protection. It emphasises the significance of reaching the maximum ballistic limit while maintaining a lightweight armour structure by optimising the total armour thickness. This study contributes to the advancement of armour technology and enhances our understanding of the behaviour of composite materials under high-velocity impacts. It offers valuable guidance for the development of more robust armour systems suitable for various defence and protection applications.

The energy dissipation mechanism of bi-metal Kevlar\ itanium fiber metal laminate under high-velocity impact

Fiber Metal Laminate (FML) is an impact resistant material widely used in marine and aerospace engineering structures that need to withstand impact damage, especially deck and bulkhead structures. To investigate the effect of titanium skin on energy dissipation, a series of ballistic impact experiments were performed on a bi-metal FML in this study. The FML were made of Ti–6Al–4V (TC4) skins and orthogonally woven Kevlar-129 fabric impregnated with E54-epoxy resin. Thus, this FML can be also called as bi-metal Kevlar/titanium FML. In addition, a numerical model based on stress wave theory is proposed to study the energy dissipation mechanism of the bi-metal FML under high-velocity ballistic impact. The residual ballistic velocity of the numerical model is verified by the experimental data in this paper and previous experimental data, showing that the numerical model is a more efficient method to analyze the energy dissipation mechanism of bi-metal FML. According to the numerical results, as the dominant energy dissipation, the perfectly inelastic collision of titanium skins dissipated 43%–62% and 17%–27% of total energy at the high-velocity penetration and ballistic limit, respectively. However, regardless of whether the FML has been penetrated, the compression-shear of Kevlar interlayer dissipated 24%–27% of total energy. Furthermore, the numerical calculations also show that the ballistic limit increases approximately linearly with the relative titanium skin thickness when the front titanium skin of the FML is thicker. Finally, this paper proposes a simple specific energy absorption prediction formula that helps to evaluate the energy dissipation capacity of FML.

Periodically driven model with quasiperiodic potential and staggered hopping amplitudes: Engineering of mobility gaps and multifractal states

In this study, we examine whether periodic driving of a model with a quasiperiodic potential can generate interesting Floquet phases that have no counterparts in the static model. Specifically, we consider the Aubry-Andr\'e model, which is a one-dimensional time-independent model with an on-site quasiperiodic potential ${V}_{0}$ and a nearest-neighbor hopping amplitude that is taken to have a staggered form. We add a uniform hopping amplitude that varies in time either sinusoidally or as a square pulse with a frequency $\ensuremath{\omega}$. Unlike the static Aubry-Andr\'e model, which has a simple phase diagram with only two phases (only extended or only localized states), we find that the driven model has four possible phases for the Floquet eigenstates: a phase with gapless quasienergy bands and only extended states, a phase with multiple mobility gaps separating different quasienergy bands, a mixed phase with coexisting extended, multifractal, and localized states, and a phase with only localized states. The multifractal states have generalized inverse participation ratios that scale with the system size with exponents that are different from the values for both extended and localized states. In addition, we observe intricate reentrant transitions between the different kinds of states when $\ensuremath{\omega}$ and ${V}_{0}$ are varied. The appearance of such transitions is confirmed by the behavior of the Shannon entropy. Many of our numerical results can be understood from an analytic Floquet Hamiltonian derived using a Floquet perturbation theory that uses the inverse of the driving amplitude as the perturbation parameter. In the limit of high frequency and large driving amplitude, we find that the Floquet quasienergies match the energies of the undriven system, but the Floquet eigenstates are much more extended. We also study the spreading of a one-particle wave packet, and we find that it is always ballistic but the ballistic velocity varies significantly with the system parameters, sometimes showing a nonmonotonic dependence on ${V}_{0}$ that does not occur in the static model. Finally, we compare the results for the driven model, which has a static staggered hopping amplitude, with a model that has a static uniform hopping amplitude, and we find some significant differences between the two cases. All of our results are found to be independent of the driving protocol, either sinusoidal or square pulse. We conclude that the interplay of the quasiperiodic potential and driving produces a rich phase diagram that does not appear in the static model.

Numerical study on influence of target thickness on impact response of GFRP composites

Due to rise in threats like ballistic impacts, blast loading and vehicle collision in armored military vehicles, the demand for materials with high strength and enhanced energy absorption capacity has been increased. Applications of Fiber reinforced composites as armor material in military vehicles is being considered as one of the measures to reduce such threats. The focus of this work is to investigate the energy absorption capacity of a GFRP plates subjected to a rigid projectile with blunt-nosed at the intermediate velocity range by using non-linear finite element code LS-DYNA. It has been found that the numerically computed results of ballistic limit velocity and residual velocity, closely resemble the test results reported in the literature. With altering target thickness, it has also been explored how the energy absorption capacity, projectile's residual velocity, ballistic velocity limit and damage mechanism of composite. The numerical results make it evident that the target thicknesses have a significant impact on the target's ballistic resistance and delamination area.

Bioinspired nacre-like steel-polyurea composite plate subjected to projectile impact

Natural marine biological structures have evolved over a long period of time, and their comprehensive performance has huge advantages over artificial materials. In order to improve the overall strength of the artificial structure, inspired by the layered structure of nacre, a nacre-like steel-polyurea composite plate was designed as a new impact-resistant structure. On this basis, the damage deformation of three different layered steel-polyurea composite plates with nacre-like structure under different projectile velocities was simulated. The damage failure morphology of nacre-like composite plates with different layered numbers was analyzed, and consequently, five failure toughening mechanisms of nacre-like composite plates were summarized. Then, the fitted ballistic performance curves were used to compare the ballistic performance of nacre-like composite plates with different delamination, and it was found that the composite plates could reduce the residual ballistic velocity by 24.58% and increase the ballistic limit by 27.86%, and the energy dissipation mechanism of the composite plates was explained by the energy release of steel and polyurea layers. Finally, the theoretical analysis reveals that the increase in the delamination number can effectively increase the equivalent modulus of the nacre-like composite plate, thus enhancing the penetration resistance of the composite plate.

Ballistic dynamics of flexural thermal movements in a nanomembrane revealed with subatomic resolution.

Flexural oscillations of freestanding films, nanomembranes, and nanowires are attracting growing attention for their importance to the fundamental physical and optical properties and device applications of two-dimensional and nanostructured (meta)materials. Here, we report on the observation of short–time scale ballistic motion in the flexural mode of a nanomembrane cantilever, driven by thermal fluctuation of flexural phonons, including measurements of ballistic velocities and displacements performed with subatomic resolution, using a free electron edge-scattering technique. Within intervals <10 μs, the membrane moves ballistically at a constant velocity, typically ~300 μm/s, while Brownian-like dynamics emerge for longer observation periods. Access to the ballistic regime provides verification of the equipartition theorem and Maxwell-Boltzmann statistics for flexural modes and can be used in fast thermometry and mass sensing during atomic absorption/desorption processes on the membrane.

Ballistic Properties and Izod Impact Resistance of Novel Epoxy Composites Reinforced with Caranan Fiber (Mauritiella armata).

Natural lignocellulosic fibers (NFLs) possess several economic, technical, environmental and social advantages, making them an ideal alternative to synthetic fibers in composite materials. Caranan fiber is an NFL extract from the leafstalk of the Mauritiella armata palm tree, endemic to South America. The present work investigates the addition of 10, 20 and 30 vol% caranan fiber in epoxy resin, regarding the properties associated with Izod notch tough and ballistic performance. Following ASTM D256 standards, ten impact specimens for each fiber reinforcement condition (vol%) were investigated. For the ballistic test, a composite plate with 30 vol%, which has the best result, was tested with ten shots, using 0.22 ammunition to verify the energy absorption. The results showed that when compared to the average values obtained for the epoxy resin, the effect of incorporating 30 vol% caranan fibers as reinforcement in composites was evident in the Izod impact test, producing an increase of around 640% in absorption energy. Absorbed ballistic energy and velocity limit results provided values similar to those already reported in the literature: around 56 J and 186 J, respectively. All results obtained were ANOVA statistically analyzed based on a confidence level of 95%. Tukey’s test revealed, as expected, that the best performance among the studied impact resistance was 30 vol%, reaching the highest values of energy absorption. For ballistic performance, the Weibull analysis showed a high R2 correlation value above 0.9, confirming the reliability of the tested samples. These results illustrate the possibilities of caranan fiber to be used as a reinforcement for epoxy composites and its promising application in ballistic armor.

A modified model to predict the ballistic limit of a cubic fragment penetrating Kevlar / titanium fiber metal laminate

Fiber-Metal laminate (FML) is widely used in marine, military, and aerospace fields for structural protection due to its lightweight and high strength. Compared with the expensive impact experiments, a simple analytical method to predict the ballistic limit of FML is more effective and efficient. In the study, a total of 8 groups of experimental tests have been designed and implemented to investigate the ballistic resistance of bi-metal 2/1 FML which consists of two Ti-6Al-4V skins and a Kevlar core made of Kevlar-129/E54-epoxy resin. A general ballistic impact system is used to provide impact velocity greater than 800 m/s in the tests. All the specimens include the front and rear titanium skin in the same thickness, and the Kevlar core in the middle. In addition, a modified theory based on the energy dissipation is proposed to consider the effects of fragment deformation, which has been neglected by other researchers. Several modified theoretical formulas are initiated and then validated by the experimental data. As a result, the residual ballistic velocities of FMLs can be calculated from the modified theoretical formulas. It is found that the modified model can predict the ballistic limit of FML and analyze energy absorption, with certain application prospects.

Protostellar discs subject to infall: a one-dimensional inviscid model and comparison with ALMA observations

ABSTRACT A new one-dimensional, inviscid, and vertically integrated disc model with prescribed infall is presented. The flow is computed using a second-order shock-capturing scheme. Included are vertical infall, radial infall at the outer radial boundary, radiative cooling, stellar irradiation, and heat addition at the disc-surface shock. Simulation parameters are chosen to target the L1527 IRS disc which has been observed using Atacama Large Millimeter Array (ALMA). The results give an outer envelope of radial infall and uϕ ∝ 1/r which encounters a radial shock at rshock ∼ 1.5 × the centrifugal radius (rc) across which the radial velocity is greatly reduced and the gas temperature rises from a pre-shock value of ≈25 to ≈180 K over a spatially thin region calculated using a separate shock structure code. At rc, the azimuthal velocity uϕ transitions from being ∝ 1/r to being nearly Keplerian. These results qualitatively agree with recent ALMA observations which indicate a radial shock where SO is sublimated as well as a transition from a uϕ ∼ 1/r region to a Keplerian inner disc. However, in one set of observations, the observed position-velocity map of cyclic-C3H2, together with a certain ballistic maximum velocity relation suggests that the radial shock coincides with a ballistic centrifugal barrier, which places the shock at rshock = 0.5rc, i.e. inward of rc, rather than outward as given by our simulations. It is argued that radial velocity plots from previous magnetic rotating-collapse simulations also indicate that the radial shock is located outward of rc. The discrepancy with observations is analysed and discussed, but remains unresolved.

A parametric study on the behavior of FMLs based on UHMWPE composite under high velocity impact loading

Numerical parametric study is performed to investigate ballistic impact performance of a novel fiber metal laminate (FML) based on ultra-high molecular weight polyethylene (UHMWPE) fiber composite and aluminum 2024-T3 layers. A finite element modeling is developed and validated with experimental tests. A user-defined material subroutine based on continuum damage mechanics is used to define damage constitutive model of UHMWPE composite. High velocity impact simulations shows similar modes of failure to that observed in experiments. The effect of various parameters such as metal thickness, composite core thickness, metal volume fraction (MVF), and lay-up sequence on ballistic limit velocity, absorbed energy and specific perforation energy (SPE) of samples has been investigated. The results show that increasing the number of composite layers increases the SPE while increasing the thickness of metal layers decreases the SPE. Although, as the core thickness increases, the growth of SPE decreases. Changes in the lay-up sequence do not have much effect on ballistic velocity and absorbed energy. Whereas, the MVF is an important parameter in the high velocity impact performance of the PERALL specimens. In addition, with equal MVF, stacking sequence change has no significant effect on the ballistic limit velocity. Finally, a simple linear equation is suggested to describe the relationship between MVF and specific perforation energy.

Analysis of Ballistic Impact Performance and Shear Effect on Elastomeric and Thermoset Composites

This study proposes a new theoretical model for high-velocity impact in two kinds of targets, Kevlar/elastomer and Kevlar/epoxy composites, and comprehensively discusses and compares these. In this analysis, with the aid of hyperelasticity theory, energy absorption equations are derived based on the linear and nonlinear behavior of constituents to assess the dependence of the ballistic limit on the interaction of the first, second, third, and fourth layers of the laminate on each other. Furthermore, to investigate the matrix effect on the in-plane shear, tensile tests were performed at [Formula: see text] direction for both Kevlar/elastomer and Kevlar/epoxy composite laminates. The results indicate that the adhesion of Kevlar fibers to the rubber matrix is more substantial than their adhesion to the epoxy matrix, increasing the failure shear strain of elastomeric composites and reducing the debonding between the fiber and the matrix which led to greater ballistic velocity. The results of the experimental tests verified the proposed model and confirmed its precision. With this verified model, the thickness effect on the ballistic behavior of the targets was investigated.