The size effect in mechanical properties of finite-sized graphene nanoribbon

Chu, Yanbang; Ragab, Tarek; Basaran, Cemal

doi:10.1016/j.commatsci.2013.08.016

Cited by 77 publications

(54 citation statements)

References 26 publications

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“…(11) and Eqs. (12), namely a 2 = c 2 , in accord with the results in Ref. 28, and supporting our further assumptions.…”

Section: Secular Equations Of Phonon Dispersions In Graphenesupporting

confidence: 92%

“…size effects. 12 Peng et al 13 and Wei et al 14 developed methods to obtain continuum description of non-linear elastic properties of nano-materials by expanding the elastic strain energy density in a Taylor series of strain with the fifth-or higher order terms truncated, while the independent constants were increased to fourteen. Therefore, we are motivated to seek another theoretical approach to construct a concise and effective continuum model of monolayer graphene.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical consideration of a microcontinuum model of graphene

et al. 2016

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A microcontinuum model of graphene is proposed based on micromorphic theory, in which the planar Bravais cell of graphene crystal is taken as the basal element of finite size. Governing equations including the macro-displacements and the micro-deformations of the basal element are modified and derived in global coordinates. Since independent freedom degrees of the basal element are closely related to the modes of phonon dispersions, the secular equations in micromorphic form are obtained by substituting the assumed harmonic wave equations into the governing equations, and simplified further according to the properties of phonon dispersion relations of two-dimensional (2D) crystals. Thus, the constitutive equations of the microcontinuum model are confirmed, in which the constitutive constants are determined by fitting the data of experimental and theoretical phonon dispersion relations in literature respectively. By employing the 2D microcontinuum model, we obtained sound velocities, Rayleigh velocity and elastic moduli of graphene, which show good agreements with available experimental or theoretical values, indicating that the current model would be another efficient and reliable methodology to study the mechanical behaviors of graphene.

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“…(11) and Eqs. (12), namely a 2 = c 2 , in accord with the results in Ref. 28, and supporting our further assumptions.…”

Section: Secular Equations Of Phonon Dispersions In Graphenesupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Theoretical consideration of a microcontinuum model of graphene

et al. 2016

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“…We introduced a pair of single-layer GNSs with an area of 8 nm × 5 nm into a BCC α-Fe matrix with a lattice constant of 2.85 Å by removing one layer of Fe atoms in the same area, where the GNS content was 0.7 vol %. The size and volume fraction picked here is not far from reality, which based on the other references, wherein the graphene size was chosen to 2.02 × 4.25 nm 2 for graphene sheet [19] and 4-12 nm for graphene nanoribbons [23] for the MD simulations, and from experimental results, the volume fraction of graphene reinforcement was 1.13 vol % in GO reinforced iron matrix composites [20] and 0.2 vol % in graphene-based Al composites [7]. Comparing the system potential energy values after removing 1-3 layers of iron atoms, the total energy was the lowest when the GNS was added after removing only one layer of iron atoms, associated with the atomic structures, listed in Table 1.…”

Section: Model Setup and Interatomic Potentialmentioning

confidence: 99%

Interaction of Edge Dislocations with Graphene Nanosheets in Graphene/Fe Composites

et al. 2018

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Abstract:Graphene is an ideal reinforcement material for metal-matrix composites owing to its exceptional mechanical properties. However, as a 2D layered material, graphene shows highly anisotropic behavior, which greatly affects the mechanical properties of graphene-based composites. In this study, the interaction between an edge dislocation (b = 1/2 (111)) and a pair of graphene nanosheets (GNSs) in GNS reinforced iron matrix composite (GNS/Fe) was investigated using molecular dynamic simulations under simple shearing conditions. We studied the cases wherein the GNS pair was parallel to the (110), (112), and (111) planes, respectively. The results showed that the GNS reinforcement can effectively hinder dislocation motion, which improves the yield strength. The interaction between the edge dislocation and the GNS pair parallel to the (112) plane showed the strongest effect of blocking dislocations among the three cases, resulting in increases in the shear modulus and yield stress of 107% and 1400%, respectively. This remarkable enhancement was attributed to the Orowan "by-passing" strengthening mechanism, whereas cross-slip of dislocation segments was observed during looping around GNSs. Our results might contribute to the development of high-strength iron matrix composites.

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“…The initial C-C atomic bond length used in the simulations is 1.40 Å , which is slightly lower than the average value of bond lengths in bulk graphene. Choosing such bond length helps reducing the initial stress in GNR and shortens the time needed to reach thermodynamic equilibrium (Chu and Basaran, 2012;Chu et al, 2016Chu et al, , 2014bChu et al, , 2015bHumphrey et al, 1996).…”

Section: Simulationsmentioning

confidence: 99%

“…At the same time, it was observed that using the same value for D max and D min will have similar results as shown in Figure 3 (stress-strain diagrams 3, 4, 5, and 6) for the fracture strength around 100 GPa which is considered reasonable. Following the previous study by Chu et al (2014b), same D max and D min cutoff distance of 2.0 Å is used (Fu et al, 2016;LAMMPS, 2010).…”

Section: Simulationsmentioning

confidence: 99%

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

Ragab

Basaran

2018

International Journal of Damage Mechanics

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Molecular dynamics simulations of armchair graphene nanoribbons and zigzag graphene nanoribbons with different sizes were performed at room temperature. Double vacancy defects were introduced in each graphene nanoribbon at its center or at its edge. The effect of defect on the mechanical behavior was studied by comparing the stress-strain response and the fracture toughness of each pair of pristine and defective graphene nanoribbon. Results show that the effect of vacancies in zigzag graphene nanoribbon is more profound than in armchair graphene nanoribbon. Also, the effect of double vacancy defect on the ultimate failure stress is greater in zigzag graphene nanoribbons than in armchair graphene nanoribbon due to bond orientation with respect to loading direction. Strength reduction can be as high as 17.5% in armchair graphene nanoribbon with no significant difference between single and double vacancies, while for zigzag graphene nanoribbon, the strength reduction is up to 30% for single vacancy and 43% for double vacancy defects. It is observed that for zigzag graphene nanoribbon with double vacancy at the edge, the direction of the failure plane is oriented at AE30 with respect to the loading direction while it is always perpendicular to the direction of loading in armchair graphene nanoribbon. Results have been verified through studying the fracture toughness parameters in each case as well.

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The size effect in mechanical properties of finite-sized graphene nanoribbon

Cited by 77 publications

References 26 publications

Theoretical consideration of a microcontinuum model of graphene

Theoretical consideration of a microcontinuum model of graphene

Interaction of Edge Dislocations with Graphene Nanosheets in Graphene/Fe Composites

Comparison of fracture behavior of defective armchair and zigzag graphene nanoribbons

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