Showing papers on "Ballistic impact published in 2018"
TL;DR: In this article, a methodology is presented for evaluating a strain rate sensitivity parameter for plastic deformation of bulk metallic materials, which involves ballistic impact with a hard spherical projectile, followed by repeated FEM modelling, with predicted outcomes (displacement-time plots and/or residual indent shapes) being systematically compared with experiment.
51 citations
TL;DR: In this article, the effect of hygrothermal aging on the high speed impact resistance of carbon fiber reinforced composites (CFRP) was investigated using short beam shear tests.
47 citations
TL;DR: In this paper, a finite element methodology to predict the behaviour of Dyneema® HB26 fiber composites at quasi-static rates of deformation, under low velocity drop weight impact, and high velocity ballistic impact has been developed.
Abstract: A finite element methodology to predict the behaviour of Dyneema® HB26 fibre composites at quasi-static rates of deformation, under low velocity drop weight impact, and high velocity ballistic impact has been developed. A homogenised sub-laminate approach separated by cohesive tied contacts was employed. The modelling approach uses readily available material models within LS-DYNA, and is validated against experimental observations in literature. Plane-strain beam models provide accurate mechanisms of deformation, largely controlled through Mode II cohesive interface properties and kink band formation. Low velocity drop weight impact models of HB26 give force-deflection within 10% of new experimental observations, with in-plane shear strain contour plots from models directly compared with experimental Digital Image Correlation (DIC). Ballistic impact models utilising rate effects and damage showed similar modes of deformation and failure to that observed in literature, and provide a good approximation for ballistic limit under 600 m/s impact speed.
45 citations
TL;DR: The dual phase STF is a combination of nanosilica and calcium carbonate dispersed in polyethylene glycol and ethanol as discussed by the authors and its assimilation into aramid fibers has been accomplished through the combination of ultrasonic dispersion and airbrush.
Abstract: The dual phase STF is a combination of nanosilica and calcium carbonate dispersed in polyethylene glycol and ethanol. Its assimilation into aramid fibers has been accomplished through a combination of ultrasonic dispersion and airbrush. This technique led to an increase of the inter-yarn friction and the projectile’s deformation. It also led to an increase on damaged layers, but at same time, the trauma cavity volume was reduced. From the ballistic tests performed, the 25% w/w nanosilica and 75% w/w calcium carbonate (STF4) combination obtained the best result. The work done by the soft ballistic plate into the body’s tissue was reduced by 40% with the same ballistic protection of traditional bullet proof vests. A 19 layers of aramid fibers impregnated with STF4 proved to have the same ballistic performance of a traditional 32 layers of aramid fibers bullet proof vest.
42 citations
TL;DR: In this paper, the role of through-the-thickness (TTT) reinforcement was investigated to suppress the inter-laminar matrix crack propagation and increase the material ballistic impact resistance for low velocity impact and high velocity impact.
36 citations
TL;DR: In this article, the combined effects of individual ply orientations and material properties on the impact performance of multi-layered, non-stitched woven aramid fabrics are studied using 2-and 4-sided clamping configurations.
34 citations
TL;DR: In this paper, a non-dimensional formulation of two analytical models has been developed (one for thin laminates and the other for thick ones) for the ballistic impact on E-glass woven fibres/polyester composite plates.
Abstract: This paper deals with the problem of high-velocity impact of a low-mass projectile on woven composite plates. A nondimensional formulation of two analytical models has been developed (one for thin laminates and the other for thick ones). Both analytical models are based on energy conservation and have been applied for the ballistic impact on E-glass woven fibres/polyester composite plates. The results of the models (mainly the ballistic limits) have been compared with experimental results. The value of the ratio target thickness/projectile diameter determining whether the laminate behaves as thick or thin has been established.
31 citations
TL;DR: In this paper, it was shown that a cylindrical projectile penetrates the plate at a lower velocity than a spherical one, which is explained by spalling-like failure for thicker graphitic membranes.
31 citations
TL;DR: In this paper, the protection property of aluminum alloy sandwich panels with honeycomb cores under the attack of bullets or debris, quasi-static perforation, and ballistic impact tests were conducted.
Abstract: To study the protection property of aluminum alloy sandwich panels with honeycomb cores under the attack of bullets or debris, quasi-static perforation, and ballistic impact tests were conducted, i...
29 citations
TL;DR: In this article, the influence of each elastic constant of Dyneema yarn model in modelling a single layer yarn woven fabric against ballistic impact using the orthogonal experiment method was analyzed.
29 citations
TL;DR: In this article, the authors investigated the ballistic behavior of a thermoset polyester resin laminated hybrid composite reinforced with a natural fiber mat and aramid fabric after exposure to UV radiation.
Abstract: Mobile ballistic armors, particularly those intended for personal protection, are also designed with lowest possible weight. Composite materials are the best choice for this kind of application, especially laminated composites reinforced with high-performance fibers or fabrics. Owing to environmental problems, research works on hybrid composites based on natural instead of synthetics fibers is already a promising line of investigation. These composites, when used outdoors, are exposed to ultraviolet (UV) radiation and some properties and applied behavior may change. Therefore, this work investigated the ballistic behavior of a thermoset polyester resin laminated hybrid composite reinforced with a natural fiber mat and aramid fabric after exposure to UV radiation. The mat was produced with curaua fiber, one of the strongest natural fibers. Infrared spectroscopy analysis and determination of the degree of cross-linking, to identify possible structural changes in the curaua mat, are performed after two different exposure times to UV radiation The mechanism of failure related to the ballistic impact is analyzed by visual inspection. The results show that the composite is influenced by UV radiation, which affects the ballistic performance due to delamination on the interface of plies as well as chain scission on curaua fibers and increasing crosslinking of the polyester resin. The delamination was attributed to a low interfacial energy between the polyester matrix and curaua fibers.
TL;DR: In this paper, the experimental testing and simulation results of ballistic impact tests on laminated armor samples that consist of three layers of different materials: fiber-cement, Kevlar fabric, and steel were presented.
Abstract: This paper presents the experimental testing and simulation results of ballistic impact tests on laminated armor samples that consist of three layers of different materials: fiber-cement, Kevlar fabric, and steel. In experimental tests, a 9 mm FMJ bullet was launched towards a 100 cm2 sample of the armor from the fiber-cement side. Ansys Workbench Explicit Dynamics and Ansys AUTODYN 3D were used to model and simulate the ballistic impact. Experimental testing and simulation results were compared to analyze the behavior of composite armor designs, and a good agreement was observed.
TL;DR: In this paper, the authors presented the first fully validated and predictive capability to model the V0-V100 probabilistic penetration response of a woven fabric using a yarn-level fabric finite element model.
TL;DR: In this paper, the mechanical behavior of chonta palm wood (Bactris gasipaes) microparticles reinforced high density polyethylene (HDPE) under high strain-rate compressive and ballistic impact loading were investigated.
TL;DR: In this paper, an enhanced version of the effective-rate-dependent nonlocal damage model was proposed to simulate the response of concrete in such events, where a new damage variable was added to the formulation in order to take the damage of the material matrix observed while porosity reduces during compaction into account.
TL;DR: In this article, a triaxially braided polymer matrix composites were used to study the heat generated in the material due to projectile velocity and penetration damage, and the authors performed impact experiments on the composite.
Abstract: Ballistic impact experiments were performed on triaxially braided polymer matrix composites to study the heat generated in the material due to projectile velocity and penetration damage. Triaxially...
TL;DR: This study fully demonstrated that choosing gelatin as muscle simulant was reasonable, however, the maximum temporary cavity diameter in the gelatin was a little larger than that in the muscle, and the expansion period of temporary cavity was longer in the Gelatin.
Abstract: Gelatin is commonly used in ballistic testing as substitute for biological tissue. Comparison of ballistic impact effects produced in the gelatin and living tissue is lacking. The work in this paper was aimed to compare the typical ballistic impact effects (penetration trajectory, energy transfer, temporary cavity) caused by 4.8mm steel ball penetrating the 60kg porcine hind limbs and 10wt% gelatin. The impact event in the biological tissue was recorded by high speed flash X-ray machine at different delay time, while the event in the gelatin continuously recorded by high speed video was compared to that in the biological tissue. The collected results clearly displayed that the ballistic impact effects in the muscle and gelatin were similar for the steel ball test; as for instance, the projectile trajectory in the two targets was basically similar, the process of energy transfer was highly coincident, and the expansion of temporary cavity followed the same pattern. This study fully demonstrated that choosing gelatin as muscle simulant was reasonable. However, the maximum temporary cavity diameter in the gelatin was a little larger than that in the muscle, and the expansion period of temporary cavity was longer in the gelatin. Additionally, the temporary cavity collapse process in the two targets followed different patterns, and the collapse period in the gelatin was two times as long as that in the muscle.
12 Sep 2018-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the tensile behavior of a cylindrical dog-bone was investigated at different temperatures and strain-rates, and the thermal softening effect was investigated in quasi-static as well as in dynamic loading conditions from room temperature up to 400 °C.
Abstract: The simulation of impact scenario against a structure requires the use of material models able to reproduce all aspects of the mechanical behaviour of the involved materials; plastic flow is one of the main aspects to be reproduced. In more detail, attention has to be paid to the investigation of strain-rate and temperature sensitivities, as well as their interaction, which necessitates the use of a reverse engineering approach. The present paper mainly focuses on the tensile behaviour and an ad-hoc testing campaign was performed on cylindrical dog-bone specimens made in Al6061T6 at different temperatures and strain-rates extending the range up to a level where, at present, there is a lack in the scientific literature. The thermal softening effect was investigated in quasi-static as well as in dynamic loading conditions from room temperature up to 400 °C; while the material strength dependence on the strain-rate was studied up to 104 s−1 on miniaturized samples. Microstructure analyses were performed to better investigate the mechanical response at different loading conditions. The parameters of the Johnson-Cook model were identified starting from experimental data via a numerical inverse approach based on FEM simulations. These parameters can be used for simulations of extreme loading scenario like ballistic impact events.
TL;DR: In this article, a comparative analysis of the dynamic behavior of nanoscale thin films made from multilayer graphene (MLG), polymer, gold, and aluminum under high-speed projectile impact is presented.
Abstract: It is crucial to investigate the dynamic mechanical behavior of materials at the nanoscale to create nanostructured protective systems that have superior ballistic impact resistance. Inspired from recent experimental advances that enable ballistic materials testing at small scales, here we report a comparative analysis of the dynamic behavior of nanoscale thin films made from multilayer graphene (MLG), polymer, gold, and aluminum under high-speed projectile impact. We employ atomistic and coarse-grained (CG) molecular dynamics (MD) simulations to measure the ballistic limit velocity (V50) and penetration energy (Ep) of these nanoscale films and investigate their distinctive failure mechanisms over a wide range of impact velocities (Vi). For the local penetration failure mechanism observed in polymer and metal films, we find that the intrinsic mechanical properties influence Ep at low Vi, while material density tends to govern Ep at high Vi. MLG films uniquely show a large impact propagation zone (IPZ), which transfers the highly localized impact energy into elastic deformation energy in a much larger area through cone wave propagation. We present theoretical analyses that corroborate that the size of IPZ should depend not only on material properties but also on a geometrical factor, specifically, the ratio between the projectile radius and film thickness. This study clearly illustrates how material properties and geometrical factors relate to the ballistic penetration energy, thereby allowing a quantitative comparison of the nanoscale ballistic response of different materials.
TL;DR: In this paper, the effects of inter-yarn friction in the fabrics impacted by a cylindrical-nose projectile on the ballistic performance including transverse deformation of fabrics, overall energy absorption and the forms of energy absorption.
TL;DR: In this article, the authors studied the behavior of composite materials for ballistic impact and found significant amount of energy absorption in rubber, almost 10 times as compared to JE plate, while damage observed was ductile in the case of rubber, while brittle in JE.
TL;DR: In this paper, a meso-scale modeling approach was employed to capture the behavior of para-aramid fabrics using LS-DYNA software, and the quasi-static mechanical properties of fabric yarns were defined by standard tensile tests, whereas the Johnson-Cook strain rate was applied to approximate the strain rate dependence of yarn tensile strength.
TL;DR: In this paper, the effect of lateral displacement was examined for cross-ply laminates and the number of failed fibers was quantitatively determined and found to generally decrease from the impact surface to the rear surface.
TL;DR: In this article, the impact performance of the composite based on glass and aramid fiber reinforced polybenzoxazine/polyurethane composites was evaluated and the results indicated that such panels have an excellent ballistic characteristics to be used as raw material to manufacture body armor.
17 Sep 2018
TL;DR: In this paper, the effect of laminated aluminium-steel panel with different configurations in a high-speed impact test was presented, and the performance of each configuration plate in terms of ballistic limit velocity, penetration process and permanent deformation was quantified.
Abstract: This paper presents the effect of laminated aluminium-steel panel with different configurations in a high-speed impact test Layering aluminium plate with high strength steel has become an interest in reducing the overall density of armour vehicle body while improving the ballistic resistance Different layering configurations differ in laminated panel performance Two layering configurations of double-layered panel achieving 25% of existing panel weight reduction were tested using experiment and computational method to investigate their behaviours when impacted with 762-mm full metal jacket at velocity range of 800–850 m/s The ballistic performance of each configuration plate in terms of ballistic limit velocity, penetration process and permanent deformation was quantified and considered Laminated panel with aluminium as the front layer reduced the ballistic performance of existing panel to 50% and the other panel maintained its performance Thus, the laminated panel with aluminium as the back layer can be used in designing a protective structure for armoured vehicle while maintaining the performance of the existing vehicle in achieving weight reduction
TL;DR: In this paper, the quasi-static compressive experimental for four types of aluminum foam with different densities were carried out and the modified constitutive model was presented based on experimental results.
Abstract: To study plastic deformation and energy absorption capability of monolithic, double layered steel plates and sandwich plates with steel skins and aluminum foam core, the quasi-static compressive experimental for four types aluminum foam with different density are carried out. The modified constitutive model is presented based on experimental results. The virtual tests using numerical simulation method by finite element code LS-DYNA were conducted with different impact velocities based on quasi-static experimental parameters. Energy absorption effect of projectile shape, skins thickness, core thickness and core densities on the plastic deformation and energy absorption capability of sandwich plates are discussed. It was shown that mechanics properties of aluminum foam with different density can be described accurately by modified constitutive model. For spaced type plate, the space between first layered and second layered targets have a significant impact on plastic deformation and energy capability. With the increase of impact velocity, the absorbed energy of plates first decreased from the ballistic limit to a minimum value and then increased monotonically.
TL;DR: In this paper, eddy current pulsed thermography was used to evaluate ballistic impact damages in basalt-carbon hybrid fiber-reinforced polymer composite laminates for the first time, to the authors' knowledge.
Abstract: In this paper, eddy current pulsed thermography was used to evaluate ballistic impact damages in basalt-carbon hybrid fiber-reinforced polymer composite laminates for the first time, to our knowledge. In particular, different hybrid structures including intercalated stacking and sandwich-like sequences were used. Pulsed phase thermography, wavelet transform, principle component thermography, and partial least-squares thermography were used to process the thermographic data. Ultrasound C-scan testing and X-ray computed tomography were also performed for comparative purposes. Finite element analysis was used for validation. Finally, an analytical and comparative study was conducted based on signal-to-noise ratio analysis.
TL;DR: In this paper, the ballistic impact behavior of carbon fiber/epoxy composite and steel metal structures with a spherical ball projectile is numerically evaluated and the ABAQUS/Explicit software is used to predict the structural response and the damage progression and absorbed energy in the target plates.
Abstract: In this paper, ballistic impact behavior of carbon fiber/epoxy composite and steel metal structures with a spherical ball projectile is numerically evaluated. ABAQUS/Explicit software is used to predict the structural response and the damage progression and absorbed energy in the target plates. The predicted damage mechanisms, velocity–time profile and energy absorption threshold of the two target structures agreed very well with results in the reference. Result found the model ballistic limit prediction of 134 m/s. Result also shows that carbon/epoxy composite can withstand higher impact and exhibit excellent energy-absorbing characteristics under high-velocity impact loading conditions than steel metal structures. Therefore, carbon/epoxy composite is considered suitable for applications in automobile and aerospace structures for optimum efficiency.
TL;DR: In this article, an experimental study was carried out to analyze the deformation failure mechanisms of 3D braided carbon fiber reinforced Plastics (CFRPs) subjected to ballistic impact loading.
TL;DR: In this paper, the response to ballistic impact of alumina-ultra high molecular weight polyethylene (UHMWPE) composites with different relative concentrations of alumin was investigated.
Abstract: The response to ballistic impact of alumina-ultra high molecular weight polyethylene (UHMWPE) composites with different relative concentrations of alumina was investigated. The impact tests were carried out at subsonic speed using a compressed air system. The results showed that the depth of penetration (DOP) in a Medium Density Fiberboard (MDF) bulkhead protected by a disk of the composite decreased with increasing concentration of alumina in the composite. Scanning electron microscopy (SEM) images of composites with 80 %, 85 % and 95 % alumina showed transgranular, intergranular and ductile fracture mechanisms.