Atomistic-scale simulations of mechanical behavior of suspended single-walled carbon nanotube bundles under nanoprojectile impact (original) (raw)
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Carbon nanotubes as a player to improve mechanical shock wave absorption
Composites Part B: Engineering, 2018
The overall goal of the research is to develop a composite simultaneously able to absorb mechanical shocks. In this paper, carbon nanotubes (CNTs) based polymers were used to enhance the wave absorption capacity against shock load. The material consists of an epoxy polymer reinforced with various concentrations of CNTs: 1%, 2% and 4wt%. An experimental procedure was developed for material characterization. The specimen was sandwiched between two steel bars (incident and transmitted bars), with 20 mm in the diameter. The shock wave was generated by a launching device drives the striker to hit one bar, and then the wave propagates throughout the specimen. Two strain gauges were placed on the surface of each bar with 1 m of the distance from the specimen surface. The wave intensity was recorded using a data acquisition system (HBM GEN3i model). The full histories of strain, force and the energy absorption during the shock time were measured. With 4 % mass fraction of CNTs, the shock wave intensity was reduced to 33.34% compared to 0% of CNTs. The results show also that the specimen with CNTs is able to absorb high energy impacts.
Dynamic Strengthening of Carbon Nanotube Fibers under Extreme Mechanical Impulses
Nano Letters, 2019
A monofilament fiber spun from individual carbon nanotubes is an arbitrarily long ensemble of weakly interacting, aligned, discrete nanoparticles. Despite the structural resemblance of carbon nanotube monofilament fibers to crystalline polymeric fibers, very little is known about their dynamic collective mechanics, which arise from van der Waals interactions among the individual carbon nanotubes. Using ultrafast stroboscopic microscopy, we study the collective dynamics of carbon nanotube fibers and compare them directly with nylon, Kevlar, and aluminum monofilament fibers under the same supersonic impact conditions. The in situ dynamics and kinetic parameters of the fibers show that the kinetic energy absorption characteristics of the carbon nanotube fibers surpass all other fibers. This study provides insight into the strain-rate-dependent strengthening mechanics of an ensemble of nanomaterials for the development of high-performance fibers used in body armor and other protective nanomaterials possessing exceptional stability in various harsh environments.
Dynamic response of phenolic resin and its carbon-nanotube composites to shock wave loading
Journal of Applied Physics, 2011
We investigate with nonreactive molecular dynamics simulations the dynamic response of phenolic resin and its carbon-nanotube ͑CNT͒ composites to shock wave compression. For phenolic resin, our simulations yield shock states in agreement with experiments on similar polymers except the "phase change" observed in experiments, indicating that such phase change is chemical in nature. The elastic-plastic transition is characterized by shear stress relaxation and atomic-level slip, and phenolic resin shows strong strain hardening. Shock loading of the CNT-resin composites is applied parallel or perpendicular to the CNT axis, and the composites demonstrate anisotropy in wave propagation, yield and CNT deformation. The CNTs induce stress concentrations in the composites and may increase the yield strength. Our simulations suggest that the bulk shock response of the composites depends on the volume fraction, length ratio, impact cross-section, and geometry of the CNT components; the short CNTs in current simulations have insignificant effect on the bulk response of resin polymer.
High-velocity impact of a hybrid CBN nanotubes
Oxford Open Materials Science, 2020
Nanomaterials under extreme conditions can behave in a completely different manner. High-velocity impact, for example, can produce nanoribbons without any chemical approach via carbon or boron nitride nanotubes unzipping. Although hybrid nanostructures have been used to create stronger structures, few studies on these materials under extreme conditions have been employed. In this work, we studied, using fully atomistic reactive molecular dynamics simulations an experimentally synthesized hybrid nanotube (boron nitride and carbon nanotubes concentrically assembled) under the high-velocity impact. Our results show that the combination of elastic and brittle materials can produce different structures, such as nanoribbons and boron nitride atomic chains. These results can have a significant impact on the production of new nanostructures.
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.
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.
Effective interatomic potential for modelling shock waves in carbon nanotube bundles
MATHEMATICS EDUCATION AND LEARNING
Carbon nanotubes (CNTs) are grown as forests on a variety of substrates and can be horizontally aligned and compacted to produce super-strong ropes and yarns. CNT bundles can be used for shock and vibration protection. It is of interest to analyze the energy absorption by CNT bundles during dynamical loading. In this work, we develop an effective interatomic potential for simulating the propagation of shock waves in the transverse direction of a CNT bundle within the framework of a one-dimensional model. The potential parameters are fitted to the results of molecular dynamics simulation of a CNT bundle under lateral compression. The developed one-dimensional model is capable of reproducing propagation of compressive waves associated with both elliptization and collapse of CNTs.
Facta Universitatis, Series: Mechanical Engineering
Investigations of the angled ballistic impact behavior on Carbon Kevlar® Hybrid fabrics with assorted volumes of carbon nanotubes (CNTs) into epoxy are presented. The ballistic impact behavior of the epoxy composites with/without CNTs is compared. Individual impact studies are conducted on the composite plate made-up of Carbon Kevlar Hybrid fabrics with diverse volumes of CNTs. The plate was fabricated with eight layers of equal thickness arranged in different percentages of CNTs. A conical steel projectile is considered for a high velocity impact. The projectile is placed very close to the plate, at the centre and impacted with sundry speeds. The variation of the kinetic energy, the increase in the internal energy of the laminate and the decrease in the velocity of the projectile with disparate angles are also studied. Based on the results, the percentage of CNTs for the ballistic impact of each angle is suggested. The solution is based on the target material properties at high ba...
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...
International Journal of Impact Engineering, 2012
The low-velocity impact response of thin carbon woven fabric composites reinforced with functionalized multi-walled carbon nanotubes (MWCNTs) is investigated. Three loadings of MWCNTs by weight of epoxy are examined; 0.5%, 1.0%, and 1.5%. The composite plates are subjected to five levels of energy; 15, 24, 30, 60, and 120 J. The time history response of load, displacement, velocity, and energy are measured and reported. Moreover, the composite damage, associated with each energy level, is quantified and compared between different MWCNTs loadings. It is observed that the functionalized MWCNTs enhanced the impact response and limited the damage size in the woven carbon fiber composite. The addition of 1.5% MWCNTs resulted in 50% increase in energy absorption.