Equivalent-continuum modeling of nano-structured materials

ElsevierMerli Gisbert, R.; Lazaro, C.; Monleón Cremades, S.; Domingo Cabo, A. (2013). A molecular structural mechanics model applied to the static behavior of single-walled carbon nanotubes: New general formulation. Computers and Structures. 127:68-87. doi:10.1016/j.compstruc.2012.11.023 AbstractA new general formulation for the mechanical behavior of Single-Walled Carbon Nanotubes is presented. Carbon atoms are located at the nodes of an hexagonal honeycomb lattice wrapped into a cylinder. They are linked by covalent C − C bonds represented by a truss or spring element, and the three-body interaction among two neighboring covalent bonds is reproduced by a rotational spring. The main advantage of our approach is to allow general load conditions (and any chirality) with no need of specific formulation for each load case, in contrast with previous works [26], [27], [31]. Four load configurations are adopted: tension, compression, bending and torsion of cantivelered SWCNTs. Calculations with our own codes for both AMBER and Morse potential functions have been carried out, aimed to compare their final results. Initial positions of the atoms (nodes) into nanotube cylindrical geometry has been reproduced in great detail by means of a conformal mapping from the planar graphene sheet. Therefore, the effect of initial SWCNTs curvature has been introduced explicitly through a system of initial stresses (prestressed state) which contribute to maintain their circular cross-section. Numerical results and deformed shapes for nanotubes with several diameters and chiralities under each load case are used to obtain their mechanical parameters with the only objective of checking the present formulation with previous works [28], [30], [20], [24]. Also, the significance of the atomistic discrete simulations at the nano-scale size against other continuum models is underlined.

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“…This initial forces has been introduced through second terms in eqs. (21) and (23). Nevertheless, diagram in fig.…”

Section: Amber Potentialmentioning

confidence: 96%

A molecular structural mechanics model applied to the static behavior of single-walled carbon nanotubes: New general formulation

Merli

Lázaro

Monleón

et al. 2013

Computers & Structures

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“…Back in 1947 (Wallace, 1947), planar graphene was theoretically presumed not to exist in a free, stable state (Odegard et al, 2002). Within the framework of carbonbased materials, however, this 2-D material suddenly aroused the attention of scientists (Lv et al, 2011).…”

mentioning

confidence: 99%

Identification and Visualization of the Intellectual Structure in Graphene Research

Vargas-Quesada

Chinchilla‐Rodríguez

Rodríguez

2017

Front. Res. Metr. Anal.

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Since the discovery of the promising properties of graphene, research in the field has attracted numerous grants and sponsors, leading to an exponential rise in the number of papers and applications. This article presents a global map of graphene research and its intellectual structure, drawn using the terms of more than 50,000 documents extracted from Scopus database, years 1998-2015. The unit of analysis consisted of descriptors (including Author Keywords and Indexed Keywords), with the co-occurrence of descriptor as the unit of measure, using fractional counting. The main research lines identified are: Fundamental Research, Functionalization and Biomedical Applications, Technology and Devices, Materials Science, Energy Storage, Optics and Chemical Properties and Sensors. Using overlay maps, we depict the graphene research efforts of the United States, the European Union (Europe-28), and China, and project their evolution through longitudinal maps to facilitate comparison. The United States was initially at the head of world output in graphene research, but was surpassed by China in 2011 and by Europe in 2014, as a result of their respective scientific policies and financial support. The output of China has since been so intense that it can be said to mark graphene research trends. We believe this information may be valuable for the core community involved in this scientific field, as it offers a large-scale analysis showing how research has changed over time. It is therefore also helpful for policy makers and research planners. The resulting maps are a useful and attractive tool for the graphene research community, as they reveal the main lines of exploration at a glance. The methodology described here could be re-created in any other field of science to uncover and display its intellectual structure and evolution over time.

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“…The interlayer distance is ∼0.347 nm, which is approximate to the balance distance between the neighbor shells having van der Waals interaction. [18][19][20] Tang et al 13 indicated that the irreversible deformation of the multi-walled CNTs is obtained on condition that the bending angle is higher than 25 • . The irreversible deformation of the CNTs is caused by the generation of sp 3 bonds at the bending point.…”

Section: Models and Methodologymentioning

confidence: 99%

Interfacial thermal conductance of buckling carbon nanotubes

Zhang

Hao

et al. 2018

AIP Advances

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Bond transition of sp2 to sp3 in carbon nanotube can be realized through bending operation at buckling location, which affects the electronic, mechanical and thermal properties of buckled carbon nanotube. In this work, thermal properties of buckled tri-walled carbon nanotube with sp3 bonds are explored using molecular dynamics. Our results reveal that interfacial thermal conductance at buckling location is sensitive to the bending angle, which decreases exponentially with increasing bending angle until 90 degree because of increasing the number of interlayer sp3 bonds. When the bending angle is beyond 90 degree, there are sp3 bonds formed on the outer-tube walls which provide new paths for heat transfer. The insight of mechanism of thermal properties is analyzed by determining atomic micro-heat flux scattering. Our findings provide a flexible and applicable method to design thermal management device. This unusual phenomenon is explained by the micro-heat flux migration and stress distributions.

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Equivalent-continuum modeling of nano-structured materials

Cited by 581 publications

References 54 publications

A molecular structural mechanics model applied to the static behavior of single-walled carbon nanotubes: New general formulation

A molecular structural mechanics model applied to the static behavior of single-walled carbon nanotubes: New general formulation

Identification and Visualization of the Intellectual Structure in Graphene Research

Interfacial thermal conductance of buckling carbon nanotubes

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