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Mechanical characterization of nanoindented graphene via molecular dynamics simulations.

Fang TH, Wang TH, Yang JC, Hsiao YJ - Nanoscale Res Lett (2011)

Bottom Line: The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity.Resistance to deformation decreased at higher temperature.Strong adhesion caused topological defects and vacancies during the unloading process.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Rd,, Kaohsiung 807, Taiwan. fang.tehua@msa.hinet.net.

ABSTRACT
The mechanical behavior of graphene under various indentation depths, velocities, and temperatures is studied using molecular dynamics analysis. The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity. Nanoindentation induced pile ups and corrugations of the graphene. Resistance to deformation decreased at higher temperature. Strong adhesion caused topological defects and vacancies during the unloading process.

No MeSH data available.


Related in: MedlinePlus

Topographies for indentations. Indentations of (a1, a2) 0 nm, (b1, b2) 0.2 nm, (c1, c2) 0.4 nm, and (d1, d2) 0.6 nm.
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Figure 5: Topographies for indentations. Indentations of (a1, a2) 0 nm, (b1, b2) 0.2 nm, (c1, c2) 0.4 nm, and (d1, d2) 0.6 nm.

Mentions: Figure 5 shows the topographies obtained for various indentation depths. The peak is larger for a deeper indentation due to more atoms adhering to the tip. Pile ups and corrugations of the graphene occurred beneath the indenter tip. The strong adhesion led to topological defects and vacancies. Stone-Wales defects usually play an important role in the corrugation region with 5-7-7-5 ring defects [26]. We also found double vacancy (C2) defects, which are composed of one octagonal ring and two pentagonal rings, during the adhesion pulling process. Double vacancies are referred to as 5-8-5 defects [27]. Our simulation results agree with those reported by Kudin et al. [28], who investigated the Raman spectra of graphite oxide and functionalized graphene sheets with Stone-Wales defects and C2 defects [28].


Mechanical characterization of nanoindented graphene via molecular dynamics simulations.

Fang TH, Wang TH, Yang JC, Hsiao YJ - Nanoscale Res Lett (2011)

Topographies for indentations. Indentations of (a1, a2) 0 nm, (b1, b2) 0.2 nm, (c1, c2) 0.4 nm, and (d1, d2) 0.6 nm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211995&req=5

Figure 5: Topographies for indentations. Indentations of (a1, a2) 0 nm, (b1, b2) 0.2 nm, (c1, c2) 0.4 nm, and (d1, d2) 0.6 nm.
Mentions: Figure 5 shows the topographies obtained for various indentation depths. The peak is larger for a deeper indentation due to more atoms adhering to the tip. Pile ups and corrugations of the graphene occurred beneath the indenter tip. The strong adhesion led to topological defects and vacancies. Stone-Wales defects usually play an important role in the corrugation region with 5-7-7-5 ring defects [26]. We also found double vacancy (C2) defects, which are composed of one octagonal ring and two pentagonal rings, during the adhesion pulling process. Double vacancies are referred to as 5-8-5 defects [27]. Our simulation results agree with those reported by Kudin et al. [28], who investigated the Raman spectra of graphite oxide and functionalized graphene sheets with Stone-Wales defects and C2 defects [28].

Bottom Line: The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity.Resistance to deformation decreased at higher temperature.Strong adhesion caused topological defects and vacancies during the unloading process.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien Kung Rd,, Kaohsiung 807, Taiwan. fang.tehua@msa.hinet.net.

ABSTRACT
The mechanical behavior of graphene under various indentation depths, velocities, and temperatures is studied using molecular dynamics analysis. The results show that the load, elastic and plastic energies, and relaxation force increased with increasing indentation depth and velocity. Nanoindentation induced pile ups and corrugations of the graphene. Resistance to deformation decreased at higher temperature. Strong adhesion caused topological defects and vacancies during the unloading process.

No MeSH data available.


Related in: MedlinePlus