Low-Velocity Impacts on Targets Containing Embedded Carbon Nanotubes (original) (raw)
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Ballistic resistance capacity of carbon nanotubes
Nanotechnology, 2007
Carbon nanotubes have high strength, light weight and excellent energy absorption capacity and therefore have great potential applications in making antiballistic materials. By examining the ballistic impact and bouncing-back processes on carbon nanotubes, this investigation shows that nanotubes with large radii withstand higher bullet speeds and the ballistic resistance is the highest when the bullet hits the centre of the CNT; the ballistic resistance of CNTs will remain the same on subsequent bullet strikes if the impact is after a small time interval.
Deformation and damage mechanisms of multiwalled carbon nanotubes under high-velocity impact
2008
Deformation behavior and damage mechanisms of multiwalled carbon nanotubes have been studied under the high strain rate impact during cold spraying. Rippling is suggested as the mechanism for breakdown of nanotubes into smaller nanotubes and possible formation of carbon onions. Necking and cup-and-cone fracture with 70% reduction in area are observed that are comparable to mild steel fracture. Peeling off of outer walls of multiwalled carbon nanotubes is also seen due to shearing action between particles.
Mechanical behavior of carbon nanotubes-based polymer composites under impact tests
Journal of Composite Materials, 2018
This study was focused on the effect of carbon nanotubes on the impact resistance and damage evolution in laminate carbon nanotubes/epoxy composites under an impact loading. The composite panels were made from carbon fibers and carbon nanotubes randomly distributed into epoxy resin. The amount of carbon nanotubes dispersion was varied up to 4% by weight. Taylor impact tests were carried out to obtain the impact response of specimens with dimensions of 70×70×4 mm3. A projectile manufactured from a high strength and hardened steel with a diameter of 20 mm and 1.5 kg of mass was launched by a compressed gas gun within the velocity of 3 m/s, 7 m/s and 12 m/s. For the experimental test, three velocity levels were used: 3 m/s for the elastic deformation, 7 m/s for the penetration of the impactor and 12 m/s for the perforation of panels. Deformation histories and damage modes in specimens were recorded during the impact test using a high-speed camera. Processing of carbon nanotubes dispers...
2011
This study investigates low and high velocity impact response of nanocomposite containing 0.75, 1.0 and 1.5 wt% of multi-walled carbon nanotubes (MWNTs) in a Polypropylene (PP) matrix. MWNTs were incorporated into polypropylene via melt compounding in an internal mixer followed by injection molding. Izod impact test results indicated higher impact energy in nanocomposite containing MWNTs comparing with neat PP. A single stage gas gun in velocity range of 20-150 m/s using harden steel hemispherical tip projectile with diameter of 8.1 mm and weight of 11.34 g, was used to conduct high velocity impact tests. Result showed better energy absorption and ballistic limit velocity (the average of highest impact velocity causing perforation but unable to go through and lowest impact velocities with no residual velocity recording) for specimens containing MWNTs. Results eventually showed higher values for specimens containing 1 wt% MWNTs in both high and low velocity impact tests as compared with the neat PP.
Preliminary Sputter-Erosion Characterization of Multiwalled Carbon Nanotubes
40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, 2004
This paper presents preliminary results of ion sputter erosion characterization of carbon nanotubes. Relative erosion rates were compared by exposing multiwall carbon nanotubes (MWNTs), polycrystalline diamond films, amorphous carbon, and boron nitride to the exhaust plume of a 1.5-kW Hall-effect thruster operating on krypton propellant. Two types of MWNTs were investigated: films composed of vertically aligned tubes and those horizontally laid on the substrate surface. Only diamond films and vertically aligned MWNTs survived erosion by 250-eV krypton ions. The vertically aligned tubes were found to bundle at their tips into nanocones after ion erosion.
Computational Materials Science, 2018
Carbon nanotube fiber (CNTF) is generally considered a strong candidate for the fabrication of bulletresistant vests due to its excellent combination of extremely high elastic modulus, high yield strain, low density, super toughness, as well as good flexibility. CNTF may also provide effective dissipation of impact energy through fibrillation within the CNTF and through disintegration of the CNTF. In this study, molecular dynamic (MD) simulations are performed to investigate the nanoprojectile impact on suspended single-walled carbon nanotube (SWCNT) bundles. The simulated results show that the fronts of impact-induced longitudinal and transverse waves travel at speeds ranging from 18 to 20 km/s and 1.5 to 1.7 km/s in the bundles that absorb most of the nanoprojectile's initial kinetic energy. The manner in which ballistic impact energy spreads within the CNTF is predicted to be mainly through transverse waves. Acoustic vibrations of the SWCNT bundle caused by the impact-induced longitudinal and transverse waves are revealed. We propose that impact energy can be effectively dampened in a manner of generating acoustic noise and heat. The threshold of the nanoprojectile's incidental kinetic energy is calculated and is used to evaluate the breaking of SWCNT bundle. The destructive role of a lap joint within the SWCNT bundle is demonstrated, as well as the role of local buckling in blocking the propagation of transverse and longitudinal waves. To facilitate the spreading of impact energy over a long distance, we propose that polymers may form an ideal matrix that should be infiltrated in the CNTF through capillary forces to increase the impact strength and to reinforce the wave spreading to release.
Journal of Mechanical Engineering, 2018
This paper presents the effects of reinforced magnesium alloy, AZ31B with carbon-nanotube (CNT) and lead (Pb), in terms of ballistic resistance. Magnesium alloys possess high energy absorption capability for impact resistance. However, its capability is limited and needs to be enhanced to resist ballistic impacts. The addition of a reinforcement material within the magnesium alloy, such as CNT or Pb, can improve impact resistance. This study is divided into two ballistic test methods, namely experiment and simulation. The samples involved are the original AZ31B and reinforced AZ31B with CNT and Pb. The projectile type used for ballistic testing was a 5.56 mm FMJ NATO at a velocity of 976 m/s and the thickness of the plate was 25 mm. The aim is to study the ability of the plate against the ballistic resistance. The ballistic experiment utilises a high speed camera, at 100,000 fps, to capture the impact occurring on the plate's surface. A Cowper-Symonds model is used for the ballistic simulation and indicates the ballistic resistance of the reinforced AZ31B with increments of CNT and Pb. The velocity of the projectile penetrating through the plate was reduced by over 45% compared to the original AZ31B alloy. Reinforcement using CNT and Pb on AZ31B improved the ballistic resistance behaviour and therefore, this material is suitable for use on ballistic panels brought to you by CORE View metadata, citation and similar papers at core.ac.uk
Composite Structures, 2018
In this paper, the effect of adding multi-walled carbon nanotubes (MWCNTs) on high-velocity impact behavior of fiber metal laminates (FMLs) was investigated. The unreinforced and reinforced FMLs with different MWCNT weight percentages of 0.25, 0.5 and 1 were manufactured and tested under high-velocity impact loading using a gas gun and a spherical projectile. Moreover, tensile tests were performed on the unreinforced and reinforced composite laminates of FMLs. Incorporating 0.5 wt% of MWCNTs into the composite laminate of FML resulted the maximum reduction of 29.8% in projectile residual velocity and the maximum increase of 18.9% in the absorbed energy during projectile perforation compared to the unreinforced FMLs. This was consistent with the tensile test results in which maximum improvements in the strength, stiffness and toughness were obtained for the 0.5 wt% MWCNT-nanocomposite. The detailed visual inspections and SEM images showed that adding MWCNTs improved the resin-fiber adhesion consequently reduced the composite delamination and matrix cracking. Conversely, MWCNTs weakened bonding between the aluminum and composite layers and allowed the aluminum layer to experience larger plastic deformation.
Dynamic Impact Absorption Behaviour of Glass Coated with Carbon Nanotubes
Journal of Surface Engineered Materials and Advanced Technology, 2013
Boro-silicate glass samples were coated with chemically treated multi-walled carbon nanotubes (MWCNTs) to study the resistance offered by the coatings under the high strain rate impact. Impact testing of these glass samples was performed on Split Hopkinson Pressure Bar (SHPB), where strain rates were varied from 500/s to 3300/s. However, the comparisons were limited to samples subjected to a strain rate of 2300/s to 3000/s so that the effect of only variable deposits of coatings on the stress-strain behavior of glass can be studied. Variable deposits (0.1 mg to 0.8 mg) of MWCNTs were coated uniformly on glass samples having a disc shape with a fixed surface area (79 mm 2) to observe the effect of the coating on the impact absorption capacity of glass. It was observed that the small thickness of about 25 µm formed due to the fact that 0.2 mg of MWCNTs deposit spread over the surface increased the impact absorption capacity of the glass pieces by nearly 70%. However, beyond this amount when the deposit was increased to 0.4 mg, the coating thickness got doubled to nearly 49 µm and this led to a fall in absorption capacity which remained static till 0.8 mg deposit. However, even this decrease in capacity was able to absorb 30% more impact than offered by pure glass sample.
Analytical Spring-Mass Model of Impact Behavior of Double-Walled Carbon Nanotubes
Challenges in Nano and Micro Scale Science and Technology, 2020
In this study, an impact behavior of spherical striker on a double-walled carbon nanotube (DWCNT) is presented based on a three degree of freedom spring-mass model and the finite element (FE) simulations. The semi-analytical solution of the transverse impact of a striker on a DWCNT is investigated by using the elasticity nonlocal theory of Euler-Bernoulli (EBT) and Timoshenko (TBT) nanobeams. The spring-mass system with spring constant is used that involves shear and bending deformation. The van der Waals (vdW) interaction between two layers of a DWCNT is included in the analytical model. The results of this analysis are compared with the results of the FE simulation. The results from the spring-mass model demonstrated good agreement with FE simulation for various values of a DWCNT dimension, chirality, boundary condition, number of layered and also striker parameters such as mass and velocity. The DWCNT independent of vdW interaction is more flexible than DWCNT with vdW forces.