Effect of defects on the local shell buckling and post-buckling behavior of single and multi-walled carbon nanotubes

Eftekhari, Mehdi; Mohammadi, Soheil; Khoei, A.R.

doi:10.1016/j.commatsci.2013.07.034

Cited by 49 publications

(18 citation statements)

References 35 publications

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“…It can be inferred that the growth of fracture in the specimen is governed by the comparative resistances to cracking of the polymer matrix and the inclusions (i.e., CNT bundles/individuals). Fractures were initiated from inside the largest bundles between 18–36% strain, which is close to the range of strain at failure reported for CNTs and graphene at room temperature (i.e., 8–20%). The initiation of the fractures from bundles is possibly due to the weak van der Waals interactions between MWCNT individuals, and the small shear strength between the MWCNT concentric layers (the average shear strength for high‐quality graphite is approximately 0.48 MPa).…”

Section: Resultssupporting

confidence: 79%

Electrical conductivity and mechanical performance of multiwalled CNT‐filled polyvinyl chloride composites subjected to tensile load

Yazdani

Smith

Hatami

2016

J of Applied Polymer Sci

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This article reports a study on the strain-sensitive conductivity (tensoresistivity) and mechanical properties of polyvinyl chloride/multiwalled carbon nanotube (PVC/MWCNT) composites subjected to tensile loading at different strain rates for potential use in sensor-enabled geosynthetics and other applications involving electrically conductive polymer composites. Results indicate that adding 0.5 wt % MWCNT to the composite results in 57% reduction in its ultimate (failure) strain and a fivefold increase in its tensile modulus while leaving its ultimate strength almost unchanged. Laser scanning confocal microscopy is used to investigate the microscopic failure mechanism of the composite and how it contributes to the strain-sensitive conductivity of the composites. It is observed that tensile fractures are initiated from inside the largest bundles between 18% and 36% strain and continue through further fractal-like fracturing in smaller bundles. Gauge factors (e.g., 3.17) comparable to or exceeding those of typical strain gauges are obtained for the composite, indicating its strong potential for structural performance monitoring and damage detection applications.

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Section: Resultssupporting

confidence: 79%

Electrical conductivity and mechanical performance of multiwalled CNT‐filled polyvinyl chloride composites subjected to tensile load

Yazdani

Smith

Hatami

2016

J of Applied Polymer Sci

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“…[ 1,2 ] This nanostructured foam-like material has shown a variety of properties ranging from; super mechanics of individual CNTs have also been investigated by discrete modeling approaches such as molecular dynamics. [ 21,22 ] This computational method allows for the detailed study of defects. However, it is not suitable for capturing the macrostructure effi ciently, due to large number of simulated particles that is required to reach the micrometer-scale for CNT arrays.…”

Section: Introductionmentioning

confidence: 99%

Effects of Nanostructure and Coating on the Mechanics of Carbon Nanotube Arrays

Poelma

Fan

et al. 2016

Adv Funct Materials

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Nanoscale materials are one of the few engineering materials that can be grown from the bottom up in a controlled manner. Here, the effects of nanostructure and nanoscale conformal coating on the mechanical behavior of vertically aligned carbon nanotube (CNT) arrays through experiments and simulation are systematically investigated. A modeling approach is developed and used to quantify the compressive strength and modulus of the CNT array under large deformation. The model accounts for the porous nanostructure, which contains multiple CNTs with random waviness, van der Waals interactions, fracture strain, contacts, and frictional forces. CNT array micropillars are grown and their porous nanostructure is controlled by the infiltration and deposition of thin conformal coatings using chemical vapor deposition. Flat‐punch nanoindentation experiments reveal significant changes in material properties as a function of coating thickness. The simulations explain the experimental results and show the novel failure transition regime that changes from collective CNT buckling toward structural collapse due to fracture. The compressive strength and the elastic modulus increase exponentially as a function of the coating thickness and demonstrate a unique dependency on the CNT waviness. More interestingly, a design rule is identified that predicts the optimum coating thickness for porous materials.

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“…Employing the TB potential in MD simulations, Eftekhari et al 29 have studied axial buckling of armchair and zigzag S/MWCNTs. From a sudden drop in the force vs. the compressive axial strain curve, the value of the critical strain was determined.…”

Section: Introductionmentioning

confidence: 99%

Buckling of single-walled carbon nanotubes using two criteria

Gupta

Agrawal

Batra

2016

Journal of Applied Physics

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We use molecular mechanics simulations with the MM3 potential to study instabilities in clampedclamped single-walled carbon nanotubes (SWCNTs) deformed in torsion and axial compression. The following are the two criteria employed to find the critical buckling strain: (i) a sudden drop in the potential energy and (ii) an eigenvalue of the mass weighted Hessian of the deformed configuration becoming zero. The instability under axial compression is investigated for zigzag and armchair SWCNTs, and that under torsional deformations is also studied for chiral tubes. In general, values of critical strains from the 2nd criterion are found to be substantially less than those from the 1st criterion. For chiral SWCNTs, the critical strains from the 2nd criterion and the potential energies at the onset of instability markedly depend upon the twisting direction. Values of buckling strains predicted from the column and the shell buckling theories are found to agree well with those obtained using the 2nd criterion. Published by AIP Publishing.

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Effect of defects on the local shell buckling and post-buckling behavior of single and multi-walled carbon nanotubes

Cited by 49 publications

References 35 publications

Electrical conductivity and mechanical performance of multiwalled CNT‐filled polyvinyl chloride composites subjected to tensile load

Electrical conductivity and mechanical performance of multiwalled CNT‐filled polyvinyl chloride composites subjected to tensile load

Effects of Nanostructure and Coating on the Mechanics of Carbon Nanotube Arrays

Buckling of single-walled carbon nanotubes using two criteria

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